Answer:
Atomic mass of Boron: 10.8 amu
Explanation:
Boron-10: (0.198)(10.013) = 1.98 amu
Boron-11: (0.802)(11.009) = 8.83 amu
Add them up: 1.98+8.83= 10.8 amu
in the laboratory, a student adds 44.2 ml of water to 20.6 ml of a 0.652 m hydroiodic acid solution. what is the concentration of the diluted solution? assume the volumes are additive.
The concentration of diluted solution is 0.2 M.
The concentration and volume are related by the formula - [tex] M_{1}[/tex] [tex] V_{1}[/tex] = [tex] M_{2}[/tex] [tex] V_{2}[/tex], where [tex] M_{1}[/tex] and [tex] M_{2}[/tex] are initial and final concentration. [tex] V_{1}[/tex] and [tex] V_{2}[/tex] are initial and final volumes.
Keep the values in relation to find the concentration of final diluted solution.
0.652 × 20.6 = [tex] M_{2}[/tex] × (44.2 + 20.6)
Performing addition on Right Hand Side
0.652 × 20.6 = [tex] M_{2}[/tex] × 64.8
Performing multiplication and division
[tex] M_{2}[/tex] = 13.43÷64.8
[tex] M_{2}[/tex] = 0.2 M
Thus, the diluted solution is 0.2 M.
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a sample of an ideal gas at 1.00 atm and a volume of 1.52 l was placed in a weighted balloon and dropped into the ocean. as the sample descended, the water pressure compressed the balloon and reduced its volume. when the pressure had increased to 70.0 atm, what was the volume of the sample? assume that the temperature was held constant.
The volume of the balloon when the balloon descended down in the water becomes 0.0217 Liters.
We know, from the Boyle's Law,
If the temperature of a gas is kept constant, the pressure of the gas and the volume of the gas becomes inversely proportional to each other.
So, we can write,
P₁V₁ = P₂V₂
Where,
P₁ is the initial pressure of the gas,
V₁ is the initial volume of the gas,
P₂ is the final pressure of the gas,
V₂ is the final volume of the gas.
According to the given condition, the initial volume of the ideal gas was 1.52 L and the initial pressure of the gas is 1 atm and the final pressure of the gas is 70 atm while the final volume is unknown,
So,
1.52 x 1 = V₂ x 70
V₂ = 0.0217 Liters.
The final Volume of the gas is 0.0217 Liters.
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copper has two stable isotopes,and , with masses of 62.939598 amu and 64.927793 amu, respectively. calculate the percent abundances of these isotopes of copper.
Considering the definition of atomic mass, isotopes and atomic mass of an element, the isotope with masses of 62.939598 amu and 64.927793 amu have percent abundances of 69.80% and 30.20% respectively.
Definition of atomic massThe atomic mass (A) is obtained by adding the number of protons and neutrons in a given nucleus of a chemical element.
Definition of isotopeThe same chemical element can have the same atomic numbers, but the number of neutrons is different. These atoms are called isotopes of the element.
Definition of atomic massThe atomic mass of an element is the weighted average mass of its natural isotopes, taking into account the relative abundance of each of them.
Atomic mass of the element in this caseIn this case, you know:
The first isotope has an atomic mass of 62.939598 amu and a percent natural abundance of x%. The second isotope has an atomic mass of 64.927793 amu and a percent natural abundance of (100 -x)%.Average mass of copper is 63.54 amu.The percent abundance can be calculated as:
62.939598 amu× (x%÷100%) + 64.927793 amu× [(100-x)%÷100%]= 63.54 amu
Solving:
62.939598 amu× x+ 64.927793 amu× (1-x)= 63.54 amu
62.939598 amu× x+ 64.927793 amu× 1- 64.927793 amu× x= 63.54 amu
62.939598 amu× x- 64.927793 amu× x= 63.54 amu - 64.927793 amu× 1
-1.988195 amu× x= -1.387793 amu
x= (-1.387793 amu)÷ (-1.988195 amu)
x= 0.6980= 69.80%
Then, (100-x)%= (100 -69.80)%= 30.2%
Finally, the isotope with mass of 62.939598 amu has a percent abundance of 69.80% and the isotope with mass of 64.927793 amu has a percent abundance of 30.20%.
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Pretest: Unit 1
Question 3 of 42
Which of the following is an example of engineering, not science?
Which of the following is an example of engineering, not science?
OA. Predicting the precipitate formed during a chemical reaction
OB. Adding lime to adjust the acidity of a lake
OC. Developing a machine to control the rate of a reaction
OD. Determining the relative reactivity of two metals
SUBMIT OA. Predicting the precipitate formed during a chemical reaction
OB. Adding lime to adjust the acidity of a lake
OC. Developing a machine to control the rate of a reaction
OD. Determining the relative reactivity of two metals
SUBMIT
Correct option is OC- Developing a machine to control the rate of a reaction according to engineering
What is engineering?
Engineering is a field that has been performed for thousands of years, but STEM education, which attempts to engage students with science, technology, engineering, and mathematics, includes it as a component.
The Parthenon, Stonehenge, and the Pyramids of Giza, among other places, are instances of engineering. However, modern engineers work in a variety of fields in addition to erecting structures.
Engineers work on a variety of things, including as cell membranes, building materials, prosthetics, increasing the efficiency of engines and vehicles, and creating renewable energy sources.
Correct option is OC- Developing a machine to control the rate of a reaction according to engineering
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Which elements has the lowest ionization energy
cs, mg, cu, ge, n, s, f
Name the two molecular compounds you think would have the same mass.
The oxides of 'C' and 'N' are the two molecular compounds having the same mass i.e. CO₂ and N₂O.
To calculate the molecular weight of a molecule, individual atomic masses of various elements are added.
Given: The atomic mass of 'C' = 12u
The atomic mass of 'N' = 14u
The atomic mass of 'O' = 16u
∵Molecular weight of CO₂ = 12+16+16 = 44g/mol
The molecular weight of Carbon Dioxide is 44g/mol.
∵Molecular weight of N₂O = 14+14+16 = 44g/mol
The molecular weight of Nitrous Oxide is 44g/mol.
Molecular compounds having the same mass are known as Isobars. Isobaric properties are:
Same physical behaviorDifferent chemical behaviore.g.: Ar and Ca
Which of the following Periodic Table trends (characteristics) is incorrect?
a) electron affinity decreases from top to bottom on the periodic table
b) electronegativity decreases left to right across the periodic table
c) atomic radii decreases left to right across the periodic table
d) ionization energy decreases from top to bottom on the periodic table
(b) electronegativity decreases left to right across the periodic table
Electronegativity increases from left to right in a period across the periodic table.
Electronegativity is a relative property that defines the tendency to attract shared pair of electrons. It is a unitless parameter that is calculated by different formulae.
Pauling scale is widely used to calculate the electronegativity values of a covalent bond. e.g. F = 4.0, Cl = 3.0, etc.
⇒Electron affinity decreases from top to bottom in the periodic table.
⇒Atomic radii decrease from left to right in the periodic table.
⇒Ionization energy decreases from top to bottom in the periodic table.
a gas has an initial volume of 8.50l. what is the final volume if 355j of work is done on the gas by a constant external pressure of 1.00atm? round the answer to three significant figures.
The pressure - volume work can be determined using the change in volume ΔV and a constant pressure P. Here, the final volume for the work done of 355 J at a pressure of 1 atm is 346 l.
What is pressure -volume work done?Work done on system or by a system can be thermodynamically determined using the equations connecting the variables temperature, T pressure p and volume V.
A pressure-volume work done is the expansion or compression of a gas at constant pressure and this can be mathematically written as:
W = - P ΔV.
= -P (V2 - V1)
It is given that the initial volume V1 = 8.50 L at a pressure of 1 atm and the work done for the expansion to volume V2 is 655 J. Thus, the final volume V2 is calculated as follows:
- 355 J = 1 atm ( V2 - 8.50 L)
V2 = -355 + 8.50 L
= 346.5 L.
Here, the volume is increased highly from the initial volume so this expansion and is work done by the system. Therefore, the final volume of the system is 346 liters.
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Density is defined as
Responses
A volume/massvolume/mass
B length to mass ratiolength to mass ratio
C mass to length ratiomass to length ratio
D mass/volumemass
Answer:
D. Density is defined as mass/volume.
What best describes a solution after it has cooled
Answer: A supersaturated
this tank has been set up with cold water on one side and warm water on the other. when the divider is removed and the two water samples are allowed to mix, what is most likely to happen?
Since warm water has more energy than cold water, its molecules move more quickly than those in cold water. Gradually both the water will have same temperature according to Principle of calorimetry.
Heat lost by the hot body = heat gained by the cold body
What is principle of calorimetry?
In a calorimeter, two different types of matter are in contact with one another, ideally a liquid and a solid. Both bodies are also at various temperatures. A higher-temperature object can transfer heat energy to a lower-temperature object thanks to this setup.
Heat transfer does not stop, nevertheless, until there is a state of thermal equilibrium between the bodies. The "rule of conservation of energy," which is represented by the principle of calorimetry, states that the total amount of heat absorbed by the cold object and the total amount of heat released by the hot object are equal.
Since warm water has more energy than cold water, its molecules move more quickly than those in cold water. Gradually both the water will have same temperature
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11) A sample of gas has a volume of 823.7 mL and a pressure of 351.8 torr. What volume (in mL) will the gas occupy at 752.9 torr if the temperature of the gas doesn't change? Keep the answer with one decimal place
Answer:
384.9 mL.
Explanation:
What is given?
Volume 1 (V1) = 823.7 mL.
Pressure 1 (P1) = 351.8 torr.
Pressure 2 (P2) = 752.9 torr.
What do we need? Volume 2 (V2).
Step-by-step solution:
This is a Boyle's Law problem. Boyle's law states that the volume of a given mass of gas varies inversely with the pressure when the temperature is kept constant. An inverse relationship is described in this way. As one variable increases in value, the other variable decreases.
The formula of the law is:
[tex]P_1V_1=P_2V_2.[/tex]Where P is pressure and V is volume. We want to find volume 2, 'V2'. So let's solve for 'V2' and replace the given data that we have in the new formula:
[tex]V_2=\frac{P_1V_1}{P_2}=\frac{351.8\text{ torr}\cdot823.7\text{ mL}}{752.9\text{ torr}}=384.882\text{ mL}\approx384.9\text{ mL.}[/tex]The new volumewill be 3384.9 mL You can note as the pressure is increasing, the volume is decreasing.
A sample of 11.7 g of Fe2O3 reacts with 13.4 g CO to yield Fe and CO2.
The balanced chemical equation is:
Fe2O3(s)+3CO(g)⟶2Fe(s)+3CO2(g)
Which substance is the limiting reactant?
a. CO2
b. Fe
c. Fe2O3
d. CO
What is the theoretical yield of Fe?
mass of Fe: _________ g
If the actual experimental yield for Fe is 7.00 g, what is the percent yield of Fe?
percent yield: _________ %
In first place, the balanced reaction is:
Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
Fe₂O₃: 1 moleCO: 3 molesFe: 2 molesCO₂: 3 molesThe molar mass of the compounds is:
Fe₂O₃: 159.7 g/moleCO: 28 g/moleFe: 55.85 g/moleCO₂: 44 g/moleThen, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:
Fe₂O₃: 1 mole ×159.7 g/mole= 159.7 gramsCO: 3 moles ×28 g/mole= 84 gramsFe: 2 moles ×55.85 g/mole= 111.7 gramsCO₂: 3 moles ×44 g/mole= 132 gramsLimiting reagentThe limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction.
Limiting reagent in this caseTo determine the limiting reagent, it is possible to use a simple rule of three as follows: if by stoichiometry 84 grams of CO reacts with 159.7 grams of Fe₂O₃, 13.4 grams of CO reacts with how much mass of Fe₂O₃?
mass of Fe₂O₃= (13.4 grams of CO× 159.7 grams of Fe₂O₃)÷ 84 grams of CO
mass of Fe₂O₃= 25.476 grams
But 25.476 grams of Fe₂O₃ are not available, 11.7 grams are available. Since you have less mass than you need to react with 13.4 grams of CO, Fe₂O₃ will be the limiting reagent.
Theoretical yieldThe theoretical yield is the maximum amount of product that could be formed from the given amounts of reagents.
Theoretical yield of FeConsidering the limiting reagent, the following rule of three can be applied: if by reaction stoichiometry 159.7 grams of Fe₂O₃ form 111.7 grams of Fe, 11.7 grams of Fe₂O₃ form how much mass of Fe?
mass of Fe= (11.7 grams of Fe₂O₃×111.7 grams of Fe) ÷159.7 grams of Fe₂O₃
mass of Fe= 8.183 grams
Then, the theoretical yield of Fe is 8.183 grams.
Percent yieldThe percent yield is the ratio of the actual return to the theoretical return expressed as a percentage.
The percent yield is calculated as the experimental yield divided by the theoretical yield multiplied by 100%:
percent yield= (actual yield÷ theoretical yield)×100%
Percent yield for the reaction in this caseIn this case, you know:
actual yield= 7 gramstheorical yield= 8.183 gramsReplacing in the definition of percent yield:
percent yield= (7 grams÷ 8.183 grams)×100%
Solving:
percent yield= 85.54%
Finally, the percent yield is 85.54%.
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79.853 ml of 4.988 m sodium fluoride (aq) is added to 23.760 ml of 1.471 m beryllium sulfate. after the reaction is complete, what is the mass of precipitate that has formed?
Using the balanced reaction equation, we can calculate that the mass of the precipitate will be 1.617 g.
To solve this question, we need to write the balanced reaction equation first:
2 NaF(aq) + BeSO₄(aq) → Na₂SO₄(aq) + BeF₂(s)
We can now see that the precipitate will be beryllium fluoride. We can also see that 1 mol of beryllium sulfate reacts with 2 moles of sodium fluoride. Now we can calculate the number of moles (n) of both reactants using their molarities (c) and volumes (V):
c = n/V ⇒ n = c * V
n(NaF) = c(NaF) * V(NaF)
n(NaF) = 4.988 M * 79.854 mL = 0.3983 mol
n(BeSO₄) = c(BeSO₄) * V(BeSO₄)
n(BeSO₄) = 1.471 M * 23.3760 mL
n(BeSO₄) = 0.03439 mol
We can see that n(NaF) is more than 2 times greater than n(BeSO₄), so NaF is in excess, and BeSO₄ is the limiting reactant. Now we can calculate the number of moles of BeF₂ formed:
1 mol BeSO₄ : 1 mol BeF₂ = 0.03439 mol BeSO₄ : X
X = 0.03439 mol BeF₂
We can now convert the number of moles (n = 0.03439 mol) of BeF₂ into mass (m), using the molar mass of BeF₂ (M = 47.01 g/mol):
n = m/M ⇒ m = n * M
m = 0.03439 mol * 47.01 g/mol
m = 1.617 g
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why we can't add an ion [ H+ ] to [ H3O+ ] ???
tysmmmm
The hydrogen ion, H⁺ cannot be added to a hydronium ion, H₃O⁺ , because the hydronium ion already contains a hydrogen ion.
What are the ions, H⁺ and H₃O⁺?The ions H⁺ and H₃O⁺ are the hydrogen ion and the hydronium ion respectively.
The hydrogen ion, H⁺ is formed when a hydrogen atom loses an electron. The hydrogen ion is known as a proton.
It is produced by acids when they dissociate in solution.
The hydronium ion, H₃O⁺ is formed when a water molecule combines with a hydrogen ion.
Because a hydrogen ion cannot exist on its own in aqueous solutions, the hydronium ion is the proper representation of the hydrogen ion in aqueous solutions.
Hence, the hydrogen ion H⁺, and the hydronium ion, H₃O⁺ are used interchangeably to represent acids in solution.
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suppose, in an experiment to determine the amount of sodium hypochlorite in bleach, you titrated a 23.92 ml 23.92 ml sample of 0.0100 m k i o 3 0.0100 m kiox3 with a solution of n a 2 s 2 o 3 nax2sx2ox3 of unknown concentration. the endpoint was observed to occur at 13.80 ml 13.80 ml . how many moles of k i o 3 kiox3 were titrated?
The number of moles of k I o 3 kiox3 titrated is 2.392 x 10^-4 mol.
Concentration is the abundance of a constituent divided with the aid of the total quantity of a combination. Numerous sorts of mathematical descriptions may be prominent: mass concentration, molar concentration, number awareness, and volume awareness.
Concentration is a totally common idea used in chemistry and related fields. it is the measure of ways much of a given substance there is mixed with another substance.
Given : concentration of KIO3 = 0.0100 M
volume of KIO3 = 23.92 mL = 0.02392 L
moles of KIO3 titrated = (concentration of KIO3) * (volume of KIO3 in Liters)
moles of KIO3 titrated = (0.0100 M) * (0.02392 L)
moles of KIO3 titrated = 2.392 x 10^-4 mol
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suppose you analyze a 32.4 g sample of bleach and determine that there are 3.06 g of sodium hypochlorite present. what is the percent of sodium hypochlorite in the bleach sample? type answer:
The percent of sodium hypochlorite in the bleach sample is calculated to be 9.44% if 3.06 g of sodium hypochlorite is present.
Percentage can be calculated by dividing a value by the total value and then multiplying the resultant by 100.
In this case, we can determine the percentage of sodium hypochlorite in the bleach sample by dividing the mass of sodium hypochlorite by the total mass of the sample and then multiplying the resultant by 100 as follows;
percent of sodium hypochlorite = (mass of sodium hypochlorite/mass of sample) × 100
As 3.06 g of sodium hypochlorite is present in 32.4 g of the sample of bleach, substituting these values in the equation as follows;
percent of sodium hypochlorite = (3.06 ÷ 32.4) × 100
percent of sodium hypochlorite = 0.0944 × 100
percent of sodium hypochlorite = 9.44%
Therefore the percentage of sodium hypochlorite in the bleach sample is calculated to be 9.44%.
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when one mole of caffeine(c8h10n4o2)is burned in air 4960 kj of heat is released. 5.00g of caffeine is burned in a bomb calorimeter. the temperature is observed to increase by 11.37oc. what is the heat capacity of the calorimeter in kj/oc?
Answer:
Explanation:It is given that burning one mole of caffeine gives heat.
The given mass of caffeine is 5g.
Molar mass of caffeine can be calculated as shown below.
Calculate the number of moles of caffeine burned as follows:
Q = mc ΔT
0.0258 ×4.96 × 103 × 284.37
= 3.64 × 104J/°C
How many moles are in 2.931g of sulfur?
Which of the following diagrams has correctly shaded the metals in blue?
1) Groups of elements in the periodic table.
Metals are located in the middle and left side of the periodic table.
The second picture has correctly shaded the metals.
.
most radioactive atoms “spontaneously” decay to a more stable form. where does the “additional” energy go once the atoms have decayed to a more stable form?
When most radioactive atoms “spontaneously” decay to a more stable form the “additional” energy is converted to radiation with the emission of radioactive particles.
What is radioactivity?Radioactivity is the spontaneous decay of the nucleus of an atom with the emission of radiation and nuclear particles.
Elements that spontaneously decay are called radioactive elements.
When these radioactive elements decay, they form more stable isotopes or elements.
The spontaneous decay of atoms of radioactive elements is in order for the nucleus of the atom to become stable and non-radioactive.
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a sample of a material has 20002000 radioactive particles in it today. your grandfather measured 40004000 radioactive particles in it 6060 years ago. how many radioactive particles will the sample have 60 years60 years from today?
The remaining mass of radioactive elements with 60 years of half-life is 1000 particles.
We need to know about the half-life of the radioactive elements to solve this problem. The radioactive element will decay over time and follow the equation
N = No(1/2)^(t/t'')
where N is the final quantity, No is the initial quantity, λ is the decaying constant, t is time and t'' is the half-life of a radioactive element.
From the question above, we know that
t'' = 60 years
No = 2000 particles
t = 60 years
Calculate the remaining mass
N = No(1/2)^(t/t'')
N = 2000 x (1 / 2)^(60 / 60)
N = 1000 particles
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What type of force would put the soccer ball in motion?
balanced
unbalanced
input
output
Type of force would put the soccer ball in motion is unbalanced force.
Unbalanced force is defined as when the net force acting on the object is not equal to zero. The unbalanced force brings an object in motion. while balanced force acting on any object does not change the state of rest or uniform motion. The soccer ball moves from one place to another because unbalanced forces are acting on the soccer ball. this means the resultant force acting on soccer ball is not equal to zero.
Thus, Type of force would put the soccer ball in motion is unbalanced force.
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Answer:
b) Unbalanced force
Explanation:
Unbalanced force is the type of force which puts the soccer ball in motion while kicking it. Hence, option (b) is the correct answer.
avogadro's law states that under constant temperature and pressure, the volume of a gas is directly proportional to the number of moles of gas. what is the relationship consistent with this statement?
According to Avogadro`s law, the volume of gas is directly proportional to number of moles of gas.
This law mathematically can be written as:
V ∝ n
V = K n
V/n = K
Where V represents the volume of gas
n represents the number of moles of gas
k is proportionality constant at a given temperature and pressure
This law explains that how equal volumes of all gases contain the same number of molecules when the temperature and pressure are the same. Similarly, this law can be used to compare the same substances under two different sets of circumstances.
V₁ / n₁ = V₂ / n₂
This equation shows that the volume of the gas increases proportionally to the amount of number of moles of gas. Similarly, if the amount of gas decreases result in decrease in number of moles. As a result, neither the size of the molecules nor the molar mass of the gas affects how many atoms or molecules there are in a given volume of an ideal gas.
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copper(ii) ions appear blue in aqueous solution. this is the transmitted color. the wavelengths of light that are not absorbed give rise to the perceived or transmitted color of a substance. based on the principle of complementary colors, which colors and wavelengths would you expect to be the most strongly absorbed by cu 2 ions?
Based on the Principle of Complementary Colors , the colors and wavelengths expected to be the most strongly absorbed by cu 2+ ions are :-
Orange : 600–640 nm
Blue : 450–480 nm
Violet :400–450 nm
Green : 450–560 nm
Red : 640–700 nm
Yellow : 560–600 nm
Complementary color are pairs of colors which, while blended or mixed, cancel every different out (lose hue) via generating a grayscale color like white or black. whilst located next to every other, they devise the most powerful contrast for those colours. Complementary colours may also be known as "opposite colorings".
The RGB coloration version, invented inside the 19th century and absolutely advanced inside the twentieth century, uses combos of pink, inexperienced, and blue mild towards a black heritage to make the colours visible on a computer monitor or television display. Within the RGB version, the primary colors are purple, green, and blue. The complementary number one–secondary combinations are crimson–cyan, inexperienced–magenta, and blue–yellow. Inside the RGB colour version, the mild of complementary shades, consisting of pink and cyan, combined at full depth, will make white mild, for the reason that complementary hues comprise mild with the whole variety of the spectrum. If the light isn't always completely severe, the resulting mild will be gray.
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it has been found that ddt in the soil decomposes by a first-order reaction with a half-life of 12.0 years. how long would it take ddt in a soil sample to decompose from a concentration of 195 ppbm (parts per billion by mass) to 15 ppbm?
The ddt in the soil with half-life of 12 years needs 44.4 years to decompose.
We need to know about the half-life of the radioactive elements to solve this problem. The radioactive element will decay over time and follow the equation
N = No(1/2)^(t/t'')
where N is the final quantity, No is the initial quantity, λ is the decaying constant, t is time and t'' is the half-life of a radioactive element.
From the question above, we know that
t'' = 12 yr
N = 15 ppbm
No = 195
By substituting the given parameter, we can calculate the required for decomposing
N = No(1/2)^(t/t'')
15 = 195(1/2)^(t/12)
1/13 = (0.5) ^ (t/12)
t/12 = ⁰'⁵log(1/13)
t/12 = 3.7
t = 44.4 years
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Which of the following statements correctly identifies the synthesis reaction and explains why?
Only chemical reaction X, because one reactant is a compound
Only chemical reaction Y, because both reactants are elements
Neither chemical reaction X nor Y, because they have only one product
Both chemical reactions X and Y, because there are two reactants and a single product
Due to the presence of two reactants and a single product, both chemical reactions X and Y are possible.
Which of the following claims about a synthesis reaction is accurate?A synthesis reaction results in the formation of a single product that is more complicated than the initial reactants when two or more reactants are present.
Which of the following sums up a synthesis reaction the best?When two or more reactants unite to create a single product, the reaction is called a synthesis. The general equation A + B = AB is used to describe this kind of reaction.
According to the definition of synthesis reactions, two reactants unite to create a chemical. In a synthesis reaction, two or more substances mix chemically to generate a single compound or a product.
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Answer: A
Explanation: It said on Course Hero
diazomethane is a highly poisonous, explosive compound because it readily evolves n2. diazomethane has the following composition by mass: 28.57% c; 4.80% h; and 66.64% n. the molar mass of diazomethane is 42.04 g>mol. find the molecular formula of diazomethane, draw its lewis structure, and assign formal charges to each atom. why is diazomethane not very stable? explain.
The molecular formula of diazomethane is CH₂N₂, and the main reason for its instability is precisely the fact that it can very easily evolve nitrogen, as nitrogen's triple bond is one of the strongest covalent bonds in nature, and the energy released in its formation is more than enough to compensate the energy lost in the breaking of C-N bonds. The Lewis structure of diazomethane with the formal charges is attached below.
To obtain the molecular formula of diazomethane, we can imagine that we have 100 g of it. Now we can calculate the number of moles (n) for each of the elements, using their respective masses (m) and molar masses (M = 12 g/mol for carbon, 1 g/mol for hydrogen, and 14 g/mol for nitrogen):
n = m/M
n(C) = 28.57 g / 12 g/mol
n(C) = 2.38 mol
n(H) = 4.80 g / 1 g/mol
n(H) = 4.80 mol
n(N) = 66.64 g / 14 g/mol
n(N) = 4.76 mol
We now divide each of these numbers with the smallest of them (2.38) to calculate the molar ratio of the elements:
carbon: 2.38 / 2.38 = 1
hydrogen: 4.80 / 2.38 = 2
nitrogen: 4.76 / 2.38 = 2
Now we use these numbers to get the empirical formula of diazomethane: CH₂N₂.
The molar mass of the empirical formula is:
12 g/mol + 2 * 1 g/mol + 2 * 14 g/mol = 42 g/mol
Since this value is equal to the molar mass given to us, that means that CH₂N₂ is also the molecular formula of diazomethane.
n the laboratory you dissolve 23.4 g of manganese(ii) sulfate in a volumetric flask and add water to a total volume of 500 ml. what is the molarity of the solution?
The molarity of the solution is 0.619 M if we dissolve 23.4 g of manganese(ii) sulfate in a volumetric flask and add water to a total volume of 500 ml.
What is molarity means?The molarity is equal to the moles of a solute divided by the total number of liters in the solution. The molarity of a material quantifies its concentration in a given volume of solution.
Why do we use molarity?Molarity is the concept that describes the relationship between moles of a certain solute and the volume of the supplied solution. To calculate your molarity, you must start with moles and volumes, moles and milliliters, and mass and volumes.
Molarity formula and units
The units of molarity are M or mol/L.
Molarity equation
M = moles solute/liters solution
Molarity = number of moles of solute divided by the volume of solution in a liter
= number of moles of solute × 1000/ volume of solution in the liter
= number of moles
= Mass/ molecular weight
= 23.4/151
= 0.155moles
Molarity = 0.155× 1000/250
= 0.619 M
The concentration of manganese ion = concentration of sulphate ion = 0.619 M
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Select the correct answer. the compound 1-butene is modeled here. a bond line structure of a compound having a structure as follows (h) c (h) double bond c (h) single bond c (h) 2 single bond c h 3. what would need to happen for molecules of this compound to transform into polybutene? a. covalent bonds would need to form between the molecules. b. each molecule would need to gain at least one oxygen atom. c. more double bonds would need to form in each molecule. d. hydrogen atoms would need to be transferred between molecules.
The correct answer is that a) covalent bonds need to form between molecules. The process of polymerization to polybutene doesn't require any of the other given transformations.
The polymerization process of 1-butene to polybutene includes the homolytic cleavage of the double bond and the formation of new covalent bonds between the radical formed and another molecule of 1-butene. This means that there is no need for oxidation (option b), formation of additional double bonds (option c, although the resulting molecule could also undergo polymerization, but it would not result in the formation of polybutene), or exchange of hydrogen atoms between the molecules (option d).
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Answer: A. Covalent bonds would need to form between the molecules.
Explanation: Got 100 on edmentum
