Answer
a. 74.2
Explanation
Given that:
The initial temperature, T₁ = 63.2 °C + 273 = 336.2 K
Initial pressure, P₁ = 57.3 kPa
The final volume, V₂ = 15.56 mL
Final temperature, T₂ = 138.7°C + 273 = 411.7 K
Final pressure, P₂ = 334.6 kPa
What to find:
The initial volume, V₁.
Step-by-step solution:
The initial volume, V₁ can be calculated using the combined gas law equation.
[tex]\begin{gathered} \frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2} \\ \\ V_1=\frac{P_2V_2T_1}{P_1T_2}=\frac{334.6kPa\times15.56mL\times336.2K}{57.3kPa\times411.7K} \\ \\ V_1=\frac{1750383.611\text{ }mL}{23590.41}=74.2\text{ }mL \end{gathered}[/tex]Hence, its initial volume at 63.2 °C and 57.3 kPa is 74.2 mL
A popular car has an engine that is reported to have a volume of 5840 . What is the size in cubic inches?
By using an appropriate conversion factor, the size of this popular car's engine is equal to 356.78 cubic inches.
What is a conversion factor?A conversion factor simply refers to a number that is typically used to convert a number in one (1) set of units to another, either by dividing or multiplying.
Generally speaking, an appropriate conversion factor to an equal value must be used when it is necessary to perform any mathematical conversion.
Conversion:
1 cubic centimeter = 0.061023744094732 cubic inches.
5,840 cubic centimeter = X cubic inches.
Cross-multiplying, we have:
X = 0.061023744094732 × 5,840
X = 356.78 cubic inches.
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Complete Question:
A popular car has an engine that is reported to have a volume of 5840 cm³. What is the size in cubic inches?
Which statement best describes a weak base in solution?A. The base forms a concentrated solution.B. The base dissociates completely.C. The base forms a dilute solution.D. The base dissociates slightly.
Answer:
[tex]D[/tex]Explanation:
Here, we want to get the definition of a weak base
A weak base is a base that does not dissociate completely in solution.
What this means is that when the base is placed in a solution, its dissociation into the corresponding metallic and hydroxide ions is incomplete
what percent of a sample of As-81 remains un decayed after 43.2 seconds
The percentage of the sample of As-81 remaining undecayed after 43.2 seconds is 40.6%
How to determine the percentage remaining undecayedWe'll beging by calculating the number of half lives that has elapsed. This can be obtained as follow
The following data were obtained from the question:
Time (t) = 43.2 secondsHalf-life (t½) of As-81 = 33 secondsNumber of half-lives (n) =?n = t / t½
n = 43.2 / 33
n = 1.3
Finally, we shall determine the percentage remaining undecayed. This is shown below:
Original percentage (N₀) = 100%Number of half-lives (n) = 1.3Percentage remaining (N) = ?N = N₀ / 2ⁿ
N = 100 / 2^1.3
N = 40.6%
Thus, we can conclude that the percenatge undecayed is 40.6%
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Calculate the number of moles of magnesium, chlorine, and oxygen atoms in 8.30 moles of magnesium perchlorate,Mg(Cl04)2Express the number of moles of Mg, Cl, and O atoms numerically, separated by commas.moles of Mg, CI, O =
The question requires us to calculate the number of moles of each element (magnesium, chlorine and oxygen) in 8.30 moles of the compound magnesium perchlorate (Mg(ClO4)2).
From the molecular formula of magnesium perchlorate we can take the following information:
- in 1 mol of Mg(ClO4)2, there is only 1 mol of Mg;
- in 1 mol of Mg(ClO4)2, there are 2 moles of Cl;
- in 1 mol of Mg(ClO4)2, there are 8 moles of O.
With the information above, and knowing that the amount of Mg(ClO4)2 given by the question was 8.30 moles, we can calculate the amount, in moles, of each element:
1 mol Mg(ClO4)2 --------------- 1 mol Mg
8.30 mol Mg(ClO4)2 ---------- x = 8.30 mol Mg
1 mol Mg(ClO4)2 --------------- 2 mol Cl
8.30 mol Mg(ClO4)2 ---------- y = 2 x 8.30 mol Cl = 16.6 mol Cl
1 mol Mg(ClO4)2 --------------- 8 mol O
8.30 mol Mg(ClO4)2 ---------- z = 8 x 8.30 mol O = 66.4 mol O
Therefore, there are 8.30, 16.6 and 66.4 moles of Mg, Cl and O in 8.30 moles of magnesium perssufate.
A chemist prepares a solution of magnesium fluoride (MgF2) by measuring out 6.73mg of magnesium fluoride into a 250.mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in mol/L of the chemist's magnesium fluoride solution. Round your answer to 3 significant digits.
We have to find the molarity of a solution of Magnesium Fluoride. The definition of molarity is:
Molarity = moles of solute/Volume of solution in L
Our solute is MgF₂:
Molarity = moles of MgF₂ / L of solution
From the problem we know that the volume of the solution that the chemist prepared is 250. mL, we will have to convert that into L.
We know that there are 1000 mL in 1 L. So:
1 L = 1000 mL
250. mL = 250. mL * 1 L/1000 mL = 0.250 L
Volume of solution in L = 0.250 L
Now we have to find the number of moles of MgF₂ that the chemist added. From the problem we know the mass of MgF₂ added. Let's convert it to g:
1000 mg = 1 g
mass of MgF₂ = 6-73 mg
6.73 mg = 6.73 mg * 1 g/1000 mg = 0.00673 g
mass of MgF₂ = 0.00673 g
When we want to find the number of moles that we ave in a certain amount of a compound, we have to use the molar mass. Let's find the molar mass of MgF₂.
According to the periodic table the atomic mass of Mg is 24.3 amu and the atomic mass of F is 19 amu. So the molar mass of MgF₂ is:
molar mass of MgF₂ = 24.3 + 2 * 19 = 62.3 g/mol
molar mass of MgF₂ = 62.3 g/mol
Using the molar mass we can find the number of moles that we have in 6.73 mg or 0.00673 g of MgF₂:
moles of MgF₂ = 0.00673 g/(62.3 g/mol)
moles of MgF₂ = 1.08 * 10^-4 moles
So the chemist added 1.08 * 10^-4 moles of MgF₂ in 0.250 L of solution. Then the molarity of the solution is:
Molarity = moles of solute/Volume of solution in L
Molarity = 1.08 * 10^-4 moles/0.250 L
Molarity = 4.32 * 10^-4 M
So the answer to our problem is 4.32 * 10^-4 M
What is the total pressure of the mixture in torr?
In this question, we have to find the total pressure in the container that has 758 mmHg of pressure of cyclopropane, and 0.483 atm of pressure of Oxygen, the answer must be provided in torr:
First thing we need to do is to transform mmHg of cyclopropane to atm
1 atm = 760 mmHg
x atm = 758 mmHg
x = 0.997 atm of pressure of cyclopropane
Now that we have both pressures in atm, we can add them and then we will find the total pressure:
Ptotal = PO2 + Pcyclo
Ptotal = 0.483 + 0.997
Ptotal = 1.48 atm of total pressure
To transform to torr:
1 atm = 760 torr
1.48 atm = x torr
x = 760 * 1.48
x = 1125 torr of pressure is the total pressure
What is the mass of 32.1 mL the density of copper is 8.96 g/mL
Answer:
288 g.
Explanation:
Measurements => Density.
Density is the ratio of the mass of an object to its volume:
[tex]D=\frac{m}{V},[/tex]where D is density, m is mass, and V is volume.
We have two data: the volume (32.1 mL) and the density (8.96 g/mL) and we need to find the mass.
We can solve for 'm' in the given equation and replace the given data, as follows:
[tex]\begin{gathered} m=D\cdot V, \\ \\ m=8.96\frac{g}{mL}\cdot32.1\text{ mL,} \\ \\ m=287.6\text{ g}\approx288\text{ g.} \end{gathered}[/tex]The answer would be that the mass is 288 g.
The following lists consists of ionic compounds EXCEPT
barium hydroxide, zinc carbonate, ammonium sulfate
calcium chloride, carbon disulfide, magnesium nitrate
sodium sulfate, copper(II) oxide, potassium nitride
aluminium sulfide, sodium sulfite, calcium fluoride
The following lists consists of ionic compounds except carbon disulfide (CS₂).
Barium hydroxide , Ba(OH)₂ is an ionic compound.
zinc carbonate, ZnCO₃ is an ionic compound.
ammonium sulfate , (NH₄)₂SO₄ is an ionic compound.
calcium chloride, CaCl₂ is an ionic compound.
carbon disulfide, CS₂ is not an ionic compound. In carbon disulfide both the elements are non metallic elements. The bond formed between atoms are by sharing of electron known as covalent bond due to very little difference in electronegativity.
magnesium nitrate, Mg(NO₃)₂ is an ionic compound.
sodium sulfate, Na₂SO₄ is an ionic compound.
copper(II) oxide, CuO is an ionic compound.
potassium nitride KNO₃ is an ionic compound.
aluminium sulfide, Al₂S₃ is an ionic compound.
sodium sulfite, Na₂S is an ionic compound.
calcium fluoride, CaF₂ is an ionic compound.
Thus, The following lists consists of ionic compounds except carbon disulfide (CS₂).
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The molecular formula of Allicin, The compound responsible for the characteristics smell of garlic, is C6H 10 OS2. A) what is the molar mass of a Allicin?B) how many moles of allicin are present in 4.20 mg of the substance?C) how many molecules of Allicin are in 4.20 mg of the substance?D) how many C atoms are present in 4.20 mg of allicin?
1) Molar mass of Allicin.
1.1- Write the formula.
[tex]C_6H_{10}OS_2[/tex]1.2- Look for the molar mass of each element in the formula.
C: 12.011 g/mol
H: 1.008 g/mol
O: 15.999 g/mol
S: 32.06 g/mol
1.3- Count how many atoms are there in the formula.
C: 6
H: 10
O: 1
S: 2
1.4- Set the equation.
[tex]TheMolarMass=(6*C)+(10*H)+(1*O)+(2*S)[/tex]Plug in the known values.
[tex]TheMolarMass=(6*12.011\text{ }g/mol)+(10*1.008\text{ }g/mol)+(1*15.999\text{ }g/mol)+(2*32.06\text{ }g/mol)[/tex][tex]MM=72.066\text{ }g/mol+10.08\text{ }g/mol+15.999\text{ }g/mol+64.12\text{ }g/mol[/tex][tex]MM=162.265\text{ }g/mol[/tex]The molar mass (MM) of Allicin (C6H10OS2) is 162.265 g/mol.
2) Moles of Allicin in the sample.
Allicin sample: 4.20 mg
The molar mass of Allicin (C6H10OS2) is 162.265 g/mol.
2.1- Convert mg to g.
1g = 1000 mg
[tex]g=4.20\text{ }mg*\frac{1\text{ }g}{1000\text{ }mg}=0.00420\text{ }g[/tex]2.2- Convert grams to moles.
The molar mass of Allicin (C6H10OS2) is 162.265 g/mol.
Allicin sample: 0.00420 g
[tex]mol\text{ }C_6H_{10}OS_2=0.00420\text{ }g\text{ }C_6H_{10}OS_2*\frac{1\text{ }mol\text{ }C_6H_{10}OS_2}{162.265\text{ }g\text{ }C_6H_{10}OS_2}=0.00002588\text{ }mol\text{ }C_6H_{10}OS_2[/tex]There are 0.00002588 moles of Allicin (C6H10OS2) in 4.20 mg of substance.
The result can also be expressed as 2.588*10^(-5) mol.
3) Molecules of Allicin in the sample.
The Avogadro's number is 6.022*10^(23).
1 mol C6H10OS2 = 6.022*10^(23) molecules C6H10OS2
Allicin sample: 0.00002588 mol.
[tex]molecules\text{ }of\text{ }C_6H_{10}OS_2=0.00002588\text{ }mol\text{ }C_6H_{10}OS_2*\frac{6.022*10^{23}\text{ }molecules}{1\text{ }mol\text{ }C_6H_{10}OS_2}=1.558*10^{19}\text{ }molecules\text{ }of\text{ }C_6H_{10}OS_2[/tex]There are 1.558*10^(19) molecules in the sample.
4) C atoms in the sample of Allicin.
The ratio of carbon in one molecule of Allicin is 6 C atoms: 1 molecule of Allicin.
Allicin sample: 1.558*10^(19) molecules C6H10OS2.
[tex]C\text{ }atoms=1.588*10^{19}\text{ }molecules*\frac{6\text{ }C\text{ }atoms}{1\text{ }molecule\text{ }C_6H_{10}OS_2}=9.35*10^{19}\text{ }C\text{ }atoms.[/tex]There are 9.35*10^(19) C atoms in the sample.
A certain first-order reaction is 46% complete in 45 s. What are the values of the rate constant and the half-life for this process?
The rate constant ( k )= 9.2 x 10⁻³ s⁻¹The half life (t1/2 )= 75.3 s
It is given that the reaction is 46% complete in 45 s
The relation between rate constant and the half life can be shown as:
For first order reaction:
ln[A]=−kt+ln[A]o
46% complete, 54% remains
A = 0.54
Ao = 1
Put the value of given data in the formula:
ln A = -kt + ln Ao
ln 0.54 = -k.45 + ln 1
-0.616=-k.45
k = 13.6 x 10⁻³ s⁻¹
The half life can be determined by using the formula:
t1/2 = (ln 2) / k
t1/2 = 0.693 / 13.6 x 10⁻³
t1/2 = 0.0509 ×10⁻³ s.
t1/2 = 5.09 ×[tex]10^{5}[/tex] s.
Therefore, the rate constant for the first order reaction will be 13.6 x 10⁻³ s⁻¹ and half life will be 5.09 ×[tex]10^{5}[/tex] s.
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71.11 Liters of nitrogen gas combined with 60.6 liters of oxygen gas. What volume of nitrogen dioxide gas is made?
The reaction to produce nitrogen dioxide from nitrogen and oxygen is as follows:
[tex]N_{2(g)}+2O_{2(g)}\rightarrow2NO_{2(g)}[/tex]Since all the reactants and products are gases, we can take the coefficients as liters of substance.
Dividing the volumes we have of each reactant by their corresponding coefficient we can determine the limit reagent:
[tex]\begin{gathered} \frac{71.11LN_2}{1LN_2}=71.11 \\ \frac{60.6LO_2}{2LO_2}=30.3 \end{gathered}[/tex]From this we can conclude that the limit reagent is oxygen.
We have to base our calculations on this substance.
According to the given equation, 2 L of O2 produce 2 L of NO2, use this ratio to find the volume of nitrogen dioxide produced:
[tex]60.6LO_2\cdot\frac{2LNO_2}{2LO_2}=60.6LNO_2[/tex]It means that 60.6 liters of nitrogen dioxide gas are made.
I need help! Thank u so so much in advance
Electron capture occurs when one of the electrons in the atom is captured by the atom's nucleus. The captured electron combines with one proton to form a neutron.
We have to find the nuclide that is produced when the aluminum-28 undergoes an electron capture.
If we look for the atomic number of Al in the periodic table we will see that it is 13. That means that it has 13 protons. Then we are given the atomic mass of aluminum, it is 28. That means that if we add the number of protons and the number of neutrons we get 28.
atomic mass = n° of protons + n° of neutrons = 13 + 15 = 28
atomic number = n° of protons = 13
The nucleus of the aluminum atom will capture one electron that will combine with a proton of the nucleus to form a neutron. So the atomic number will change because it will have 1 proton less. But the atomic mass won't change because we are losing one proton but winning a neutron, so it remains the same. After the electron capture, the new nuclide will have:
atomic mass nuclide = n° of protons + n° of neutrons = 12 + 16 = 28
atomic number nuclide = n° of protons = 12
If we look for the element that has an atomic number of 12 in the periodic table we will see that it is magnesium.
Finally we can express this like a reaction:
28 0 28
Al + e --------> Mg
13 -1 12
Answer:
28
Mg
12
The local police department just bought a Reflected Ultraviolet Imaging System (RUVIS) device. What is MOST likely the purpose of this purchase?
A.
to test DNA from blood in their lab
B.
to individualize hair samples
C.
to determine if blood is human or animal
D.
to find and process more fingerprints
Answer:
To find a process more fingerprints (A uv imaging is used to capture and detect substances such as sweat which prints on a surface)
I can not figure out problem #10 b and c
b) firstly we nee dto understant that 1 ton = 2831.68 litres
therefore if 16 967.04 Litres needs transporting we simply divide the 16 967.04 by 2831.68 and the answer is 5.99 which is rounded of to 6. therefore 6 trucks will be needed
c) we need to first find out how many gallons of fuels will be needed to complete a 285 mile distance. so we divide 285 by 7.8 to get 36.54 gallons and we know the price of i gallon to be $3.95 therefoe the cost will be
3.95 x 36.54 = 144.33
the cost is $144.33 per day
A certain copper ore contains 3.24% of Cu2S by mass. In 1991, a single open-air smelt furnace heated 30000 tons of this ore. Compute the mass of copper metal obtained by this process. Enter in tons.
The mass of the copper that is obtained is 97.2 tons.
What is combustion?We can define the term combustion as the procedure by which a substance can be burnt in oxygen. We can also be able to refer to the process as roasting the object in the air. It is an oxidation reaction.
Having said all all of these, the reaction equation can be written as;
[tex]Cu_{2} S + O_{2} ------ > 2Cu + SO_{2}[/tex]
We know that the percent of the copper that it contains can now be used when we are trying to compute the mass of the copper that can be obtained from the process as we are going to have in the question that is at hand here to solve.
We are now going to proceed to see the mass of the copper that can be produced from the 300 tons of the copper I sulfide ore given.
Thus;
The mass of copper that can be obtained is;
3.24/100 * 3000 tons
= 97.2 tons
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Definition: This is a type of element or substance that is not a metal.Example: oxygen, nitrogen, hydrogen
This elements or substances that are not a metal are called non-metals.
I think that the answer is Non-metal
According to the label on a soft drink, one serving provides 185 kcal. If all of this energy is used to lift 1.0-kg blocks, how many blocks can be lifted 7.0 meters? Note: 1 J is approximately equal to the energy required to raise a 1-kg block a distance of 10 cm against Earth’s gravity.
The number of blocks that can be lifted through this height is 11563 blocks.
How many blocks can be lifted?We know that we define the term energy as the ability to do work, Now we have to consider the fact that we are told that one serving provides 185 kcal. Then we are told that all of this energy is used to lift 1.0-kg blocks through a distance of 7.0 meters.
Given that the energy exerted in lifting each block is;
mgh
m = mass of the block
g = acceleration due to gravity
h = height lifted through
E = 1.0-kg * 9.8 m/s^2 * 7.0 meters = 68.6 J or 0.016 kcal
The number of blocks that can be lifted = 185 kcal/ 0.016 kcal
= 11563 blocks
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Lithium nitride is an ionic compound. Draw a diagram which shows its formula, the charges on the ions and the arrangement of the valency (outer shell) electrons around the negative ion. Use x for an electron from a lithium atom and o for an electron from a nitrogen atom.
Lithium nitride is an ionic compound and the chemical formula of lithium nitride is Li₃N and the charges on the ions is Li⁺¹N³⁻ 3 valence electron in lithium and 5 valence electron in nitrogen
Ionic compound is the ion compound these ions are atom that gain or lose electron resulting in a net positive and negative charges and lithium nitride is an ionic compound and in that Li⁺¹N³⁻ is the ion and the arrangement of the valency (outer shell) electrons are 3 valence electron in lithium and 5 valence electron in nitrogen
X = 3 electron
O = 7 electron
And that's why lithium nitride has 10 electron
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Leslie incorrectly balances an equation as 2C4H10 + 12O2 → 8CO2 + 10H2O.Which coefficient should she change?281012
Answer: 13 O2 instead of 12 O2
Explanation:
4. An ice cube (25 g) is at -8.0°C. How much energy is required to take it to the
melting point, 0 °C? Heat capacity (c) for solid water is 2.10 J/g C
the heat energy required to take it to the melting point is 420J.
What is specific heat capacity?The heat capacity, abbreviated Cp, is the amount of heat needed to elevate a mole of a substance's heat content by precisely one degree Celsius.
A material has more thermal energy the hotter it is, says basic thermodynamics. Additionally, when a chemical is present in greater concentrations at a particular temperature, it will have a higher total thermal energy.
Mathematically,
Q = mc∆T
Where,
Q = quantity of heat absorbed by a body
m = mass of the body
∆t = Rise in temperature
C = Specific heat capacity of a substance depends on the nature of the material of the substance.
S.I unit of specific heat is J kg-1 K-1.
Given,
An ice cube of mass = m=25g
initial temperature = T1 = -8°C
final temperature = T2 = 0°C
Heat capacity for solid water = c = 2.1J/g°C
According to heat energy required to take it to the melting point,
Q = mc∆T
Q = 25g×2.1J/g°C × (0+8) °C
Q = (25×2.1×8) J
Q = 420J
Hence, the heat energy required to take it to the melting point is 420J.
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In the reaction of 2Mg + O2 →2MgO
How many moles of O2 are required to react with 14 moles of Mg?
Answer:
Explanation:The given reaction is
It is an example of an oxidation reaction because in the above reaction, is getting oxidized to form .
Also, it is a type of combination reaction because magnesium reacts with oxygen to form a single product i.e. Magnesium oxide.
What is the enthalpy change for the following reaction: C3H8(g) + 5O2 (g) --> 3CO2 (g) + 4H2O (l)ΔHof C3H8 (g) = -103.8 kJΔHof CO2 (g) = -393.5 kJΔHof H20 (l) = -285.8 kJ
The answer is -2219.9 kJ/mol
Monica works in a crime lab. Her supervisor tells her that she needs to better understand Locard’s Exchange Principle. How will she MOST accurately demonstrate her understanding of this concept?
A.
She will always test for the presence of blood at crime scenes.
B.
She will use both fingerprints and bullet matching to solve crimes.
C.
She will keep evidence separated so it doesn’t get contaminated.
D.
She will exchange information openly with other crime investigators.
She will keep evidence separated so it doesn’t get contaminated demonstrates the understanding of Locard’s Exchange Principle and is denoted as option C.
What is Locard’s Exchange Principle?This principle states that an individual who commits a crime will bring something into the crime scene and leave with something from it. This also explains that they can be used as evidence during investigation by the appropriate authorities.
Since we are aware that new substances are always brought into and carried away from the crime scene then it is best to keep the evidence separated so it doesn’t get contaminated.
This ensures that the results gotten from the analysis and investigation are accurate and is therefore the reason why option C was chosen as the correct choice.
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What is the pH of a solution in which 15 mL of 0.10 M NaOH is added to 25 mL of 0.10 M HCl?
Answer:
The pH of the solution is 1.60.
Explanation:
1st) It is necessary to write and balance the chemical reaction:
[tex]NaOH+HCl\rightarrow NaCl+H_2O[/tex]Now we can see that 1 mole of NaOH reacts with 1 mole of HCl.
2nd) We have to calculate the moles contained in 15mL of 0.10M NaOH solution and the moles contained in 25mL of 0.10M HCl solution:
• Moles contained in NaOH solution:
[tex]\begin{gathered} 1000mL-0.10moles \\ 15mL-x=\frac{15mL*0.10moles}{1000mL} \\ x=1.5*10^{-3}moles \end{gathered}[/tex]• Moles contained in HCl solution:
[tex]\begin{gathered} 1000mL-0.10moles \\ 25mL-x=\frac{25mL*0.10moles}{1000mL} \\ x=2.5x10^{-3}moles \end{gathered}[/tex]Now we know that there are 1.5x10^-3 moles of NaOH and 2.5x10^-3 moles of HCl.
3rd) According to the stoichiometry of the reaction, 1 mole of NaOH reacts with 1 mole of HCl, so in this case, 1.5x10^-3 moles of NaOH will react with 1.5x10^-3 moles of HCl, because NaOH will be the limiting reactant and HCl will be the excess reactant.
So, now we have to calculate the excess of HCl:
2.5x10^-3moles - 1.5x10^-3moles = 1x10^-3moles
Now we know that there are 1x10^-3 moles of HCl left.
4th) Excess HCl will remain dissociated into H+ and Cl-, according to the following equation:
[tex]HCl\rightarrow H^++Cl^-[/tex]That means that for every mole of HCl, 1H+ dissociates. So, in this case, there are 1x10^-3 moles of H+.
Remember that these moles are contained in 40mL, so the molarity of H+ is 0.025M:
[tex]\begin{gathered} 40mL-1x10^{-3}moles \\ 1000mL-x=\frac{1000mL*1x10^{-3}moles}{40mL} \\ x=0.025moles \end{gathered}[/tex]5th) Finally, we can calculate the pH of the solution, by replacing the H+ concentration in the pH formula:
[tex]\begin{gathered} pH=-log\lbrack H^+\rbrack \\ pH=-log\lbrack0.025\rbrack \\ pH=1.60 \end{gathered}[/tex]So, the pH of the solution is 1.60.
4 Fe + 3 O2 = 2 Fe2O3How many grams of oxygen (O2) do you needto produce 75 g Fe203?
Answer
mass of oxygen = 22.54 g
Explanation
Given:
4 Fe + 3 O2 = 2 Fe2O3
Mass of Fe203 = 75 g
Required: Mass of O2
We know:
Molar mass of Fe2O3 = 159,69 g/mol
Molar mass of O2 = 31.998 g/mol
Solution:
Step 1: Calculate the moles of Fe2O3
n = m/M where n is the moles, m is the mass and M is the molar mass
n = 75g/159,69 g/mol
n = 0.469 mol
Step 2: Use the stoichiometry to find the moles of O2
The molar ratio between Fe2O3 and O2 is 2:3
Therefore moles of O2 = 0.469 mol x (3/2) = 0.704 mol
Step 3: Find the mass of O2
m = n x M
m = 0.704 mol x 31.998 g/mol
m = 22.54 g
A lawyer is presenting a hair sample with its corresponding nuclear DNA that was found at the crime scene. How will this MOST likely affect the criminal case?
A.
The evidence will have a low probability of providing accurate matching results.
B.
The evidence will need to be looked at under a microscope to be admitted.
C.
The evidence will not be admissible in a court case.
D.
The evidence will provide a nearly exact match to the suspect’s hair.
A sample will likely affect a criminal case because this evidence will provide a nearly exact match to the suspect’s hair (Option D).
What is DNA testing?DNA testing refers to the techniques used to obtain DNA from samples that can be used to identify an individual in a police case. A sample of hair may be used for DNA testing because it contains cells and therefore also contains DNA.
Therefore, with this data, we can see that DNA testing allow us to identify individuals for which we need to obtain a sample with cells.
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Can someone help me with this pls 2. Which is the volume of 3.20 moles of O₂?7. Which is the volume of 100. of O₂?
2. Which is the volume of 3.20 moles of O₂?
We are told that at STP one mol of any gas occupies 22.4 L. We will use that relationship to find the volume occupied by 3.20 moles of O₂.
1 mol of O₂ = 22.4 L
volume of O₂ = 3.20 moles of O₂ * 22.4 L/(1 mol of O₂)
volume of O₂ = 71.7 L
Answer: 3.20 moles of O₂ occupies 71.7 L
7. Which is the volume of 100. g of O₂?
In this case we will use the same relationship, but we are given grams instead of moles. So first we have to convert the mass in grams into moles. To do that we use the molar mass of O₂.
atomic mass of O = 16.00 amu
molar mass of O₂ = 2 * 16.00
molar mass of O₂ = 32.00 g/mol
Once that we know that the mass of 1 mol of O₂ is 32.00 g, we can find the number of moles that we have in 100. g of it.
moles of O₂ = mass of O₂ /(molar mass of O₂)
moles of O₂ = 100. g/(32.00 g/mol)
moles of O₂ = 3.13 moles
Finally we can find the volume that 3.13 moles of O₂ occupies (remember that 1 mol of any gas occupies 22.4 L at STP).
volume of O₂ = 3.13 moles * 22.4 L/(1 mol)
volume of O₂ = 70.1 L
Answer: 100. g of O₂ occupies 70.1 L
Which compound results from covalent bonding? AgF K2S NaCl CO2
Answer:CO2
Explanation:
A trick that is quick and easy to use when telling covalent bonds from ionic bonds is to look at the atoms that are bonding. If there is a metal involved, then it is ionic bonding (hence AgF, NaCl. and K2S are not covalent bonding as Ag, Na, and K are all metals.
But to be more specific, ionic bonding happens when two ionic or polar atoms (atoms with non-neutral charges,) come together to balance out their charges (as negative charges will be attracted to positive charges and vice versa); the fancy term for this is electrostatic forces. They (usually) give up electrons to another atom, but do not share electrons. Covalent bonding happens when atoms actually share electrons and have their atomic orbitals overlap, meaning that the electrons actually travel through the surrounding volume of both atoms. Ionic bonded atoms will also separate into ions when in a solvent.
How fast does human hair typically grow?
A.
Two centimeters per month
B.
One inch per month
C.
One centimeter per month
D.
Two centimeters every year
Answer: One centimeter per month.
Explanation: Technically speaking, human hair grows about 1/2 inch a month or 6 inches a year. 1/2 inch is approx 1.27 centimeters, or in other words, one centimeter a month. Therefore, that's your answer.
Let me know if I got it right! :)
Answer:
1 centimeter per month
Explanation:
Human hair typically grows 6 inches in a year. Since there's 12 months, we can tell that hair grows 1/2 an inch per month. 1/2 an inch is about 1 cm.
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If 21.5 g of LiCl are dissolved 450.0 g of water at 20.0 °C in an insulated container, a temperature change is observed. The ∆H of solution of LiCl is -37.0 kJ/mol. Assuming that the specific heat of the solution is 4.184 J/(g°C), and that no heat is gained or lost by the container, what will be the final temperature of the solution?
The final temperature of the solution will be 29.5 °C.
What is the heat released when 21.5 g of LiCl is dissolved completely in water?The heat released when 21.5 g of LiCl is dissolved completely in water is determined from the enthalpy change, ∆H of the solution of LiCl as follows;
Moles of LiCl in 21.5 g = mass/ molar mass
molar mas of LiCl = 42.5 g/mol
Moles of LiCl in 21.5 g = 21.5/42.5
Moles of LiCl in 21.5 g = 0.506 moles
Heat released = 0.506 * -37.0 kJ/mol
Heat released = 18.722 kJ or 18722 J
Heat released = heat gained by solution
Temperature change of the solution = heat gained / mass * specific heat capacitymass of solution = 450 + 21.5
mass of solution = 471.5 g
Temperature change of the solution = 18722 / (471.5 * 4.184)
Temperature change of the solution = 9.5 °C
Final temperature of the solution = 20 °C + 9.5 °C
Final temperature of the solution =29.5 °C
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