Answer:
c) the atoms of gold were mostly empty space.
Explanation:
When alpha particles were shot at a gold foil target, most of the particles were un-deflected . It proved that the atom is mostly empty . The alpha particle enters the atom its velocity remains unchanged . Alpha particle has great kinetic energy due to great mass . So when it remains undeflected mostly that means the nucleus has great empty space through which alpha particle sails smoothly .
(Exercise 5.2.14 modified) A common method used to produce bleach (sodium hypochlorite) is by the reaction Cl2 + 2NaOH NaCl + NaCl + H2O. Chlorine gas is bubbled through an aqueous solution of sodium hydroxide, after which the desired product is separated from the NaCl (by product). A water-NaOH solution that contains 1200 lb of pure NaOH is reacted with 800 lb of gaseous Cl2. The NaOCl formed weighs 600 lb. a. What was the limiting reactant
Answer:
Chlorine is limiting reactant
Explanation:
Based on the reaction:
Cl₂ + 2NaOH → NaClO + NaCl + H₂O
1 mole of chlorine reacts with 2 moles of NaOH
To find limiting reactant, we need to determine the moles of the reactants:
Moles Cl₂ -Molar mass: 70.9g/mol-:
800lb Cl₂ * (453.6g / 1lb) * (1mol / 70.90g) =
5118 moles Cl₂
Moles NaOH -Molar mass: 40g/mol-:
1200lb NaOH * (453.6g / 1lb) * (1mol / 40g) =
13608 moles NaOH
For a complete reaction of 13608 moles of NaOH you need:
13608 moles NaOH * (1mol Cl₂ / 2 moles NaOH) = 6804 moles of Cl₂
As the solution contains just 5118 moles of chlorine,
Chlorine is limiting reactantLithium-4 and Lithium-5 can be defined as:
A: isotopes
B: different elements
C: ions
D: average atomic masses
Answer:
A: isotopes
Explanation:
Hello.
In this case, since isotopes are defined as atoms of the same element with the same atomic number (number of protons and electrons) but different mass number (atomic mass) we can represent them via the symbol of the element followed by a dash indicating the atomic mass of the occurring isotope, for instance, for carbon, we may find C-12, C-13 and even C-14 which is useful in dating techniques.
Therefore, Lithium-4 or Li-4 and Lithium-5 or Li-5 can be defined as isotopes.
Best regards.
When matter changes from a solid to liquid or from liquid to gas, what kind of change takes place?
Answer :-
Physical change
A student wants to burn a 1.25 mL sample of ethanol (C2H5OH, d = 0.789 g/mL) in a jar containing dry air. Assuming the air in the jar is at standard atmospheric pressure and room temperature (22 °C), what volume will the jar need to be in order to hold enough oxygen for complete combustion? Hint: Refer to the composition of dry air in the previous question. (a) Write a balanced chemical reaction for the combustion of ethanol. (b) Calculate the moles of oxygen needed to completely combust the ethanol. (c) Calculate the partial pressure of oxygen in the jar. (d) Calculate the volume of oxygen (in L) needed in t
Answer:
The volume of the jar needed in order to hold enough oxygen for complete combustion is 24.2 L
(a) C₂H₅OH + 2O₂ -------> 2CO₂ + 3H₂O
(b) The moles of oxygen needed to completely combust the ethanol is 0.0429 moles
(c) The Partial pressure of oxygen is 4346.84 Pa
(d) the volume of oxygen (in L) needed in the jar is 1.038 L
Explanation:
Given;
volume of ethanol, V = 1.25 mL
density of ethanol, ρ = 0.789 g/mL
mass of ethanol, m = ρV = (1.25 mL) x (0.789 g/mL) = 0.986g
The volume of the dry air is calculated as;
[tex]P_d = \rho _d R_d T\\\\P_d = (\frac{M_d}{V_d} )R_d T\\\\V_d = (\frac{M_d}{P_d} )R_d T\\\\V_d = (\frac{0.02897 \ (kg)}{101325 \ (Pa)} )*287 \ (J/K.kg)* 295\ (K)\\\\V_d = 0.0242 \ m^3\\\\V_d = 24.2 \ L[/tex]
(a) a balanced chemical reaction for the combustion of ethanol
C₂H₅OH + 2O₂ -------> 2CO₂ + 3H₂O
(b) The moles of oxygen needed to completely combust the ethanol.
[tex]=0.986 g \ C_2H_5OH *(\frac{1 \ mol \ C_2H_5OH}{46g \ C_2H_5OH} )*(\frac{2 \ Mol \ O_2}{1 \ mol \ C_2H_5OH} )\\\\ = 0.0429 \ mols.[/tex]
(c) the partial pressure of oxygen in the jar
Total pressure of air in the jar, Pt = 101,325 Pa
Partial pressure of oxygen = nPt
= 0.0429 x 101,325 Pa = 4346.84 Pa
(d) the volume of oxygen (in L) needed in the jar
Total volume of air in the jar = 24.2 L
The fraction of this volume by oxygen = 0.0429 mols x 24.2 L = 1.038 L
Dry air is composed of many molecules and compounds. The major quantity of molecules present in the dry air is Nitrogen, followed by oxygen, argon, carbon dioxide and many more. Dry air also has some amount of water vapor in it.
The volume of the jar needed to hold enough oxygen for complete combustion can be calculated by:
Volume of ethanol= 1.25 mlDensity of ethanol = 0.789 g/mlMass of ethanol can be calculated by:= density × volume
= 1.25 ml x 0.789 g/ml
= 0.986 g
The volume of the dry air is calculated by the following:
[tex]\text{P}_d &= \rho_d \text{R}_d \text{T}[/tex]
[tex]\text{P}_d &= \dfrac{{\text M}_d}{\text{V}_d}} \text{R}_d \text{T}[/tex]
[tex]\text{V}_d &= \dfrac{{\text M}_d}{\text{V}_d}} \text{R}_d \text{T}[/tex]
[tex]\text{V}_d &= 0.0242\; m^{3}[/tex]
[tex]\text{V}_d &= 24.2\;\text L[/tex]
Hence, the volume of the dry air is 24.2 L.
a. Balanced chemical equation for the combustion of ethanol can be written as:
C₂H₅OH + 2 O₂ -------> 2 CO₂ + 3H₂O
One molecule of ethanol reacts with two molecules of oxygen to produce two molecules of carbon dioxide and three water molecules.
b. To calculate the moles of oxygen needed for complete combustion of ethanol can be calculated as:
[tex]\begin{aligned}&=0.986g\;\text{C}_2\text{H}_5\text{OH}\times\left(\frac{1\;\text{mol}\;\text{C}_2\text{H}_5\text{OH}}{46\;g\;\text{C}_2\text{H}_5\text{OH}} \right )\times\left(\frac{2\;\text{Mol\;O}_2}{1\;\text{mol}\text{C}_2\text{H}_5\text{OH}} \right )\\&=0.0429\text{mols} \end{aligned}[/tex]
Hence, 0.0429 moles of oxygen will be needed to completely burn ethanol.
c. The partial pressure of the oxygen in the jar can be calculated by the following formula:
Given,
Total pressure of air in the jar (Pt) = 101,325 PaThe partial pressure of oxygen:= nPt
= 0.0429 x 101,325 Pa
= 4346.84 Pa
Hence, the partial pressure of oxygen will be 4346.84 Pa.
d. The volume of oxygen (in L) needed in the jar can be calculated using the volume of the jar.
The total volume of air in the jar = 24.2 LThe fraction of this volume by oxygen:= 0.0429 moles x 24.2 L
= 1.038 L
Therefore, the volume of the jar needed to hold enough oxygen for complete combustion is 24.2 L.
To learn more about combustion reaction follow the given link:
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The arrows in the chart below represent phase transitions.
Solid
Liquid
16
Gas
Which arrows represent the phase transitions in which heat energy is gained?
1, 2, and 3
2,3, and 5
3, 4, and 5
4,5, and 6
Answer:
A: 1, 2, and 3
Explanation:
mY ANSWER GOT DELETED ITS WHAT I SAID BEFORE ITS ON EDGE2020
Answer:
A. 1, 2, and 3
Explanation:
Correct on Edge 2022!!!
Good luck everyone, you got this! Have a great day!
Nutrients are added to soil with the help of?
A: decomposers
B: herbivores
C: predators
D: prey
Answer:
Decomposers
Explanation:
Decomposers, well as in the name, ingest decomposing things and or droppings, and turn it into nutrients.
A 2 mL sample of concentration 0.0043 M is measured out with a volumetric pipet and diluted to 100.0 mL. What is the concentration (in M) for this solution? Give your numerical answer to three significant figures and leave off the unit label.
Answer:
Explanation:
The dilution formula is
s₁ v₁ = s₂ v₂
s₁ = .0043
v₁= 2 mL
v₂ = 100 mL
s₂ = ?
putting the values
.0043 x 2 = s₂ x 100
s₂ = .000086 = 86.0 x 10⁻⁶
Prions are proteins with the ability to generate more prions by causing other proteins to misfold into a similar shape. Since prions are proteins, they have a genetic sequence associated with them and their ability to create more prions allows them to reproduce. Why aren’t prions considered alive?
Atoms are generally held together by attraction between neutrons and protons (the strong interaction) and stabilized by electrons. As atoms increase in mass, it becomes easier for them to have too many or too few neutrons, leading to radioactive isotopes of certain elements. What factors might allow this to happen?
Answer:
im pretty sure the answer is: alpha decay, beta decay, and gamma decay.
Explanation:
What is the wavelength of radiation that has a frequency of 5.9×1011 s−1 ?
Answer:
frequency = velocity of light /wavelength
wavelength = velocity / frequency
=3 x10^8 / 5.9 x 10^11
=0.508 x 10^-3.
Which of the following is an inference?
1. the sky is blue.
2. air pollution is responsible for the colors we see during a sunset.
3. when I touch a glass of water with ice it is cold.
4. sugar is sweet.
Answer:
2) is an inference
While 1 gram of fat provides 9 calories, 1 gram of glucose provides 4 calories. Why is that?
Answer:
fat always has more calories than glucose does
Explanation:
hope hope this helps!
Fat contains more chemical bonds than glucose.
The chemical energy stored in food substances is released when the chemical bonds in those food substances are broken down during digestion.
The more the number of chemical bonds in a food substance, the greater the energy released when 1g of that substance is is broken down.
We must recall that glucose contains only six carbon atoms while fat is composed of triglycerides having several carbon atoms. The breakdown of these many chemical bonds surely releases more energy.
Hence, 1 gram of fat provides 9 calories while 1 gram of glucose provides 4 calories.
https://brainly.com/question/857310
Lithium (Li) is in the 2nd row, so the 1st row is already full (1s2). Since lithium (Li) is in the 2nd row, the s-block, and the 1st column of that block, the electron configuration of lithium (Li) is
The electronic configuration of lithium is 1 s² 2s¹ as it has 1 electron in 2 s subshell it is a s-block element.
What is electronic configuration?
Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.
Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.
Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.
Learn more about electronic configuration,here:
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Liquid nitrogen is a very cold fluid form of nitrogen that is capable of freezing objects in very short periods of time. In fact, if a ping pong ball is placed in liquid nitrogen for a few minutes and then dropped on the floor, it shatters like glass.
What type of changes does the ball experience when it is frozen in the liquid nitrogen and then dropped on the floor?
A.
physical changes only
B.
neither physical nor chemical changes
C.
physical and chemical changes
D.
chemical changes only
plz don't give wrong asnwer
Answer:
Answer C physical and chemical
(1.7 x 10-5 m) x (3.72 x 10-4 m) *
Answer:
The answer will be 1992/5 or 398.4
what happens during the dissolution of wax in kerosene
Answer:
The wax will totally dissolve in the kerosene.
Explanation:
Hello.
In this case, since wax is more specifically known as paraffin wax which is a heavy-highly nonpolar organic compound which is largely insoluble in water due to its nonpolar nature, when dissolved in kerosene which is a highly nonpolar organic solvent we can infer that the dissolution process will rapidly undergo even at normal conditions due to the intermolecular forces joining them.
Therefore, when wax is dissolved in kerosene a complete dissolution is evidenced due to their common nature.
Best regards.
Determine whether each statement is a description of a physical property or a chemical property. Please check the box that applies.
Copper conducts heat well.
physical
chemical
Alcohol has a sweet odor.
physical
chemical
Answer:
Copper conducts heat well- physical
Alcohol has a sweet door- physical
Explanation:
Answer:
a, a
Explanation:
How many eight-packs of water would you need if 32 people
are attending your part and each consumed 2 bottles of
water?
Answer:
You would need 8 eight packs of water
Explanation:
32 x 2 (seeing as this is the amount of water each person consumes)
= 64 divided by 8 (the amount of water in each pack)
= 8 eight packs of water
Which Bohr model shows the correct # of electrons for a neutral sodium atom
that has 11 protons and 12 neutrons? *
Answer:
3 option........
Explanation:
i think
A 90-m3 basement in a residence is found to be contaminated with radon coming from the ground through the floor drains. The concentration of radon in the room is 1.5 Bq · L−1 (becquerels per liter) under steadystate conditions. The room behaves as a CMFR, and the decay of radon is a first-order reaction with a decay rate constant of 2.09 × 10−6 s−1. If the source of radon is closed off and the room is vented with radon-free air at a rate of 0.14 m3 · s−1, how long will it take to lower the radon concentration to an acceptable level of 0.15 Bq · L−1?
Answer: it will take 24.6467 min to lower the radon concentration to an acceptable level of 0.15Bq.L^-1
Explanation:
To calculate the required time, we make use of the formula
Cout = Coexp [ - ( 1/θ + k ) t ] .........lets call this equation 1
where Co is the concentration of radon( 1.5Bq.L^-1 ), Cout id the allowable radon concentration( 0.15Bq.L^-1), k is the radon decay rate constant( 2.09 * 10^-6 s^-1 ), θ is the theoretical detention time and t is the time required to lower the radon concentration.
first we find θ which is the theoretical detention time using the expression
θ = _V / Q
_V is the volume of basement (90 m^3) and Q is the rate of free air (0.14 m^3.s^-1)
so we substitute
θ = 90 / 0.14
θ = 642.857 s
Now we substitute all our values into equation 1
Cout = Coexp [ - ( 1/θ + k ) t ]
0.15 = 1.5exp [ - ( 1/642.857 + (2.09 * 10^-6) ) t ]
divide both LHS and RHS by 1.5
0.15/1.5 = exp [ - ( 0.001555 + 0.00000209)t ]
0.1 = exp[ - ( 0.001557)t ]
next we take the natural log of both sides
In 0.1 = In [ exp( -0.001557t )]
-2.3025 = - 0.001557t
t = 2.3025 / 0.001557
t = 1478.8053 sec
so we convert to minutes
t = 1478.8053 / 60
t = 24.6467 min
therefore it will take 24.6467 min to lower the radon concentration to an acceptable level of 0.15Bq.L^-1
Need Help ASAP
Thanks you
The lungs are connected to the trachea by _____. bronchi windpipes alveoli capillaries
Answer:
Bronchi
Explanation:
The trachea divides into air tubes called the bronchi, which connects it to the lungs.
Answer:
bronchi
Explanation:
Beryllium-9
Neutrons:
Protons:
Electrons:
Answer:
Neutrons - 5
Protons - 4
Electrons - 4
Explanation:
Beryllium (Be) is the 4th element on the Periodic Table.
It has 4 protons and 4 electrons (neutral charge)
Atomic Mass = # of Protons + # of Neutrons
9 = 4 + x
x = 5 Neutrons
Torque can be calculated by multiplying the force (N) applied at 90∘ to the lever arm at a distance (m) from the pivot point (point of rotation), the compound SI unit for the torque is N⋅m. If the force (at 90∘ to the lever arm) applied is 15 N and it is applied at 2.0 m from the pivot point (point of rotation), what is the torque on the lever?
Answer:
F=15 N
Moment arm=2 m
torque=Fl=15x2=30 Nm
Explanation:
determine the molarity of 3.72 moles of NaBr in 575 ml of solution
Answer:
6.47 M (3 s.f.)
Explanation:
Please see the attached picture for the full solution.
Acetone is produced from 2-propanol in the presence of dioxygen and the photocatalyst TiO2 when the reactor is irradiated with ultraviolet light. For a reaction carried out at room temperature in 1.0 mol of liquid 2-propanol containing 0.125 g of catalyst the following product concentrations were measured as a function of irradiation time. Calculate the first order rate constant.
Reaction Time min 20 40 60 80 100 120 140 160 180
Acetone Produced 1.9 3.9 5.0 6.2 8.2 10 11.5 13.2 14.0
Answer:
20 30 40 50 is the answer to that one day
How many electrons would Magnesium with a -1 charge have?
Both elements and compounds are considered to be
Answer:
Pure Substances.
Explanation:
Elements and compounds are both examples of pure substances. A substance that cannot be broken down into chemically simpler components is an element.
What is the pH of 0.10 M HNO2 solution? (Ka= 4.0 x 10-4)|
Answer:
The answer is 2.2Explanation:
Since the above substance is a weak acid it's pH can be found by using the formula
[tex]pH = \frac{1}{2} ( - log(Ka ) - log(c) )[/tex]
where
Ka is the acid dissociation constant
c is the concentration of the acid
From the question
Ka = 4.0 × 10-⁴
c = 0.1 M
So we have
[tex]pH = \frac{1}{2} ( - log(4.0 \times {10}^{ - 4} ) - log(0.1) ) \\ = \frac{1}{2} (3.4 + 1) \\ = \frac{1}{2}(4.4) \: \: \: \: \: \: \: \: [/tex]
We have the final answer as
2.2Hope this helps you
Why are nutrient molecules important?
A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excreted by cells to create non-cellular structures, such as hair, scales, feathers, or exoskeletons. Some nutrients can be metabolically converted to smaller molecules in the process of releasing energy, such as for carbohydrates, lipids, proteins, and fermentation products (ethanol or vinegar), leading to end-products of water and carbon dioxide. All organisms require water. Essential nutrients for animals are the energy sources, some of the amino acids that are combined to create proteins, a subset of fatty acids, vitamins and certain minerals. Plants require more diverse minerals absorbed through roots, plus carbon dioxide and oxygen absorbed through leaves. Fungi live on dead or living organic matter and meet nutrient needs from their host.
