Answer:
43.7
Explanation:
Volume of gas = 1.00L
Time = 12 hours
Decrease in 1 balloon = 0.200L
Decrease in second balloon = 0.0603L
R1 = rate at which helium diffuses= 0.20/12= 0.0166
R2 = rate at which heavier gas diffuses = 0.0693/12 = 0.00502
Using grahms law
R1²/R2² = m/4
= 0.0166²/0.00502² = m/4
= 10.935 = m/4
When we cross multiply
m is the molar mass of heavier gas = 43.73
Americium-241 is an alpha emitter used in household smoke detectors and K-40 is a positron emitter used to date rock samples. The daughter nuclides in these two reactions are:
Answer:
Np-237, Ar-40.
Explanation:
Alpha particle is positively charged particle having a mass of 4 unit. Hence,when alpha is removed from any isotope it produces a element having mass 4 units less than original isotope that was before emission. Americium 241 isotopes used in the smoke detector which emit an alpha particle to produce neptunium-237.
Potassium-40 emits positron which is having negative charge to lower one proton and increase one neutron number in the particle and in such way it will produce [tex]^{40}Ar_{18}[/tex] not [tex]^{40}Ca_{20}[/tex]
Answer:
Neptunium - 237 , Argon - 40 .
Explanation:
Americium - 241 ⇒ Neptunium - 237 + alpha particles
²⁴¹₉₅Am ⇒ ²³⁷₉₃Np + ⁴₂α
K-40 ⇒ Argon 40 + positron .
⁴⁰₁₉K ⇒ ⁴⁰₂₀Ar + ₁e
Convert 0.049 kg sulfur (S) to g of sulfur (S).
Answer:
The answer is
49 g of SulphurExplanation:
To convert kilograms to grams we use the conversion
1 kg = 1000 g
From the question
If 1kg = 1000 g
Then 0.049 kg = 0.049 × 1000
We have the final answer as
49 g
Hope this helps you
=====================================
A cup of gold colored metal bed was measured to have a mask for 25 g. By water displacement, the volume of the bed was calculated to be 40.0 mL. Given the following densities, identify the metal. Gold equals 19.3 g/milliliters copper equals 8.86 g/milliliters bronze equals 9.87 g/milliliters
Answer : The metal is copper.
Explanation :
As we are given that:
Mass of metal = 25 g
Volume of metal = 40.0 mL
Formula used:
[tex]\text{Density of metal}=\frac{\text{Mass of metal}}{\text{Volume of metal}}[/tex]
Now putting all the given values in this formula, we get:
[tex]\text{Density of metal}=\frac{25g}{40.0mL}[/tex]
[tex]\text{Density of metal}=8.86g/mL[/tex]
From this we conclude that the metal is copper whose density is 8.86 g/mL.
Hence, the metal is copper.
Your science teacher gives you three liquids to pour into a jar. After pouring all of them into the jar, the liquids layer as seen in the image. What property of matter prevents the three liquids from mixing together?
Answer:
density
Explanation:
Balance the chemical equation below using the smallest possible whole number stoichiometric coefficients NH3(g) + O2(g) + CH4(g) → HCN (aq) + H2O(1)
Answer:
[tex]2NH_{3 (g)} + 3O_{2 (g)} +2CH_{4 (g)} --> 2HCN_{(aq)} + 6H_{2}O_{(l)}[/tex]
Explanation:
Heat is added to a substance, but its temperature does not rise. Which one of the following statements provides the best explanation for this observation? (a) the substance must be a gas. (b) the substance must be a non-perfect solid. (c) the substance undergoes a change of phase. (d) the substance has unusual thermal properties. (e) the substance must be cooler than its environment.
Answer:
C
Explanation:
Heat is added to a substance, but its temperature does not rise
because
(c) the substance undergoes a change of phase.
Does heat change during a phase change?Heat, which is energy, either comes into the material during a change of phase or heat comes out of the material during this change.
What are the four-phase changes of heat?Melting, Condensation, Vaporization & Sublimation
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Given the following balanced chemical reaction:
3A2+B2 2A3B
If 12 moles of Az are reacted with excess B2, how many moles of A3B will be produced?
Answer:
Explanation:
according to balance chemical equation
3 A2 moles produced 2 moles of A3B
so 12 moles A2 will produced moles of A3B= 12*2/3=24/3= 8
therefore 12 moles of A2 produced 8 moles of A3B
A balanced chemical reaction is an equation that has the same number of stoichiometry coefficients on both sides. When 12 moles of A₂ react, then 8 moles of A₃B are produced.
What are excess reagents?Excess reagents are the reactants that are present in more quantity than the other reactant and are left in reaction after completion.
The balanced chemical equation:
3A₂ + B₂ → 2A₃B
From reaction: 3 moles of A₂ molecule are needed to produce 2 moles of A₃B. So, 12 moles of A₂ will produce:
(12 × 2) ÷ 3 = 8 moles
Therefore, 8 moles of A₃B will be produced from 12 moles of A₂.
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The density of a nickel coin was determined by laboratory measurement to be 728 g/mL. A nickel has a mass of 5.040 grams. What is the volume of the nickel?
0.6923 mL
0.692 ml
оооо
36.3 mL
1.43 mL
Answer:
The answer is 0.6923 mLExplanation:
The density of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]
Making volume the subject we have
[tex]volume = \frac{mass}{Density} [/tex]From the question
Density = 728 g/mL
mass of nickel = 5.040 g
Substitute the values into the above formula and solve for the volume
That's
[tex]volume = \frac{5.040}{728} \\ = 0.692307[/tex]
We have the final answer as
Volume of nickel = 0.6923 mLHope this helps you
Answer:
The answer would be 0.6923 mL :)
Identify the following as physical (P) or chemical (C) changes.
holacomo es tu pregunta nola entiendo
lanation:
Answer:
Where are the questions you want us to identify for you
Calculate the equilibrium constant for the reaction: 2 Cr + 3 Pb2+ ----> 3 Pb + 2 Cr3+ at 25oC. Eocell = 0.61 V
Answer:
The value is [tex]K = 8*10^{61}[/tex]
Explanation:
From the question we are told that
The equation is [tex]2 Cr + 3Pb^{2+} \to 3Pb + 2Cr^{3+}[/tex]
The temperature is [tex] T = 25^oC = 298 K [room \ temperature ][/tex]
The emf at standard condition is [tex]E^o_{cell} = 0.61 \ V[/tex]
Generally at the cathode
[tex]3Pb^{2+}(aq) + 6 e- --> 3Pb(s)[/tex]
At the anode
[tex]2Cr^{3+} + 6e^- \to 2Cr[/tex]
Generally for an electrochemical reaction, at room temperature the Gibbs free energy is mathematically represented as
[tex]G = n* F * E^o_{cell} [/tex]
Here n is the no of electron with value n = 6
F is the Faraday's constant with value 96487 J/V
=> [tex]G = 6 * 96487 * 0.61[/tex]
=> [tex]G = 3.5 *10^{5} \ J[/tex]
This Gibbs free energy can also be represented mathematically as
[tex]G = RTlogK[/tex]
Here R is the cell constant with value 8.314J/K
K is the equilibrium constant
From above
=> [tex]K = antilog^{\frac{G}{ RT} }[/tex]
Generally antilog = 2.718
=>[tex]K = 2.718^{\frac{3.5 *10^5}{ 8.314* 298} }[/tex]
=> [tex]K = 8*10^{61}[/tex]
7. Experimental value of acceleration due to gravity is found to be
9.842 m/s². The accepted value of acceleration due to gravity is
9.81 m/s2. What is the percent error in calculation?
a 0.326 %
b 0.316 %
C 0.981 %
d 0.613 %
Answer : The correct option is, (a) 0.326 %
Explanation :
To calculate the percentage error, we use the equation:
[tex]\%\text{ error}=\frac{|\text{ Experimental value - Accepted value}|}{\text{ Accepted value}}\times 100[/tex]
We are given:
Experimental value = 9.842 m/s²
Accepted value = 9.81 m/s²
Now put all the given values in above equation, we get:
[tex]\%\text{ error}=\frac{|9.842 m/s^2- 9.81m/s^2|}{9.81m/s^2}\times 100[/tex]
[tex]\%\text{ error}=0.326\%[/tex]
Therefore, the percent error in calculation is 0.326 %
Calculate the density of an object with a mass of 3.8 g, that when placed in a 10.0 mL graduated cylinder with an initial volume of 4.5 mL rises to a final volume of 8.6 mL. *
Answer : The density of an object is 0.93 g/mL
Explanation : Given,
Mass of an object = 3.8 g
Initial volume = 4.5 mL
Final volume = 8.6 mL
First we have to calculate the volume of an object.
Volume of an object = Final volume - Initial volume
Volume of an object = 8.6 mL - 4.5 mL
Volume of an object = 4.1 mL
Now we have to calculate the density of an object.
Formula used:
[tex]\text{Density}=\frac{\text{Mass of an object}}{\text{Volume of an object}}[/tex]
Now putting all the given values in this formula, we get:
[tex]\text{Density}=\frac{3.8g}{4.1mL}[/tex]
[tex]\text{Density}=0.93g/mL[/tex]
Therefore, the density of an object is 0.93 g/mL
A balloon has a volume of 4100 cm? What is the volume in liters?
A balloon has a volume of 4100 cm. The volume in liters is 4100000.
What are liters and cubic meters?Liters and cubic meters are the measurement unit of liquid. They are used to write the value of the measurements. There are seven basic units of measurement. The values are liters, kg, meters, grams, milliliters, etc.
A liter is a measurement unit for volume in the metric system. One liter equals 0.001 cubic meters. 1 liter equals 1000 ml. Cubic meters is the SI unit of volume. It is a volume of a cube with a length of 1 cm.
To calculate the value of cubic meters. The calculation of all dimensions is done. The dimensions include length, breadth, and height. A cubic decimeter occupies a volume of 10 cm × 10 cm × 10 cm.
Thus, the volume in liters is 4100000.
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How does the strength of the bar magnet affect the current in the pickup coil?
Answer:
The induction of current increases in the coil.
Explanation:
The strength of the bar magnet affect the current in the pickup coil because the magnetic field produced by the bar magnet interfere with the field of he coil. By moving the bar magnet in and out of the coil so induction of electric current will be occurs in the soil. If a bar magnet with more strength is moving in the coil then more current will be induced inside the coil.
Draw two cyclic constitutional isomers of cis-1-chloro-2-methylcyclobutane with the same size ring. In cases where there is only one cyclic constitutional isomer, just draw one structure.
Answer:
The drawings are in the figure attached below.
Explanation:
"Constitutional isomers" is a term used in chemistry to refer to chemical compounds that have the same constitution and molecular formula distributed in a different structure. That is, the compound has the same atoms, but when built in a three-dimensional image, these atoms occupy different places within the same structure.
Write an equation to show how perchloric acid, HClO4, reacts with water. Include states of matter in your answer. Click in the answer box to open the symbol palette.
Answer:
HClO4(aq) + H2O(l) ⇄ H3O+(aq) + ClO4-(aq)
Explanation:
When an acid dissolves in water, it will produce hydronium ion, H3O+ as the only positive ion.
perchloric acid, HClO4, being an acid will react with water, H2O to produce hydronium ion, H3O+ as shown below:
HClO4(aq) + H2O(l) ⇄ H3O+(aq) + ClO4-(aq)
How many dm³ of hydrogen,measured at s.t.p.,would be needed to reduce 47.7g of copper(II) oxide to copper?
A. 4.48
B. 6.72
C. 10.82
D. 13.44
help a friend please....will mark brainliest
Answer:
D. 13.44 dm³
Explanation:
Step 1: Write the balanced equation
CuO + H₂ ⇒ Cu + H₂O
Step 2: Calculate the mass corresponding to 47.7 g of CuO
The molar mass of CuO is 79.55 g/mol.
47.7 g × (1 mol/79.55 g) = 0.600 mol
Step 3: Calculate the moles of H₂ that react with 0.600 mol of CuO
The molar ratio of CuO to H₂ is 1:1. The moles of H₂ are 1/1 × 0.600 mol = 0.600 mol.
Step 4: Calculate the volume of 0.600 moles of H₂ at STP
1 mol of any gas at STP has a volume of 22.4 dm³.
0.600 mol × (22.4 dm³/1 mol) = 13.44 dm³
Why was 1990 an important year regarding air quality?
O The United States took first steps to keep the air clean.
O The United States created the Environmental Protection Agency.
Modifications and improvements were made to the Clean Air Act.
O Funding was established under the Clean Air Act to study air pollution.
Answer:
C. Modifications and improvements were made to the Clean Air Act.
Explanation:
The Clean Air act was originally established in 1970 and was concerned with the aim of protecting people and the environment in general from polluted air. Polluted air could cause different illnesses and environmental degradation.
The law was amended in 1990 in which modifications and improvements were made to the Clean Air Act. There was the need to reduce acid rain, toxic emissions which could deplete the ozone layer and cause varying respiratory illnesses in humans and to increase visibility.
1990 was an important year to to the United States regarding Air Quality because "Modifications and improvements were made to the Clean Air Act." (Option C)
How is this so?In reality, 1990 was an important year for air quality due to the enactment of significant amendments to the Clean Air Act in the United States.
These amendments, signed into law in November 1990, introduced stricter regulations and requirements to combat air pollution.
The amendments addressed various pollutants, including sulfur dioxide, nitrogen oxides, and hazardous air pollutants, leading to improved air quality standards and a more comprehensive approach to protecting human health and the environment from the harmful effects of air pollution.
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why is it essential to know the water temperature in this experiment- to find the vapor pressure of the water
Answer:
Vapour pressure of a liquid varies with temperature
Explanation:
The vapour pressure of any liquid is directly proportional to the temperature of the liquid. This implies that, as the temperature of the liquid increases, the vapour pressure increases likewise and vice versa.
Since the vapour pressure of liquid varies with the temperature of the liquid, it is essential to know the water temperature in the experiment to determine the vapour pressure of water.
an alligator is 213.4 cm long. how long is he in feet?
Answer:
7.00ft
Explanation:
An aqueous KNO3 solution is made using 75.1 g of KNO3 diluted to a total solution volume of 1.95 L .Calculate the molarity of the solution. (assume a density of 1.05 g/mL for the solution)
Calculate the molality of the solution.
Calculate the mass percent of the solution.
Answer:
- [tex]M=0.38M[/tex]
- [tex]\\ \% m=3.67\%[/tex]
Explanation:
Hello,
In this case, since the molar mass of potassium nitrate is 101.1 g/mol, we can compute the molarity as follows:
[tex]M=\frac{75.1g*\frac{1mol}{101.1g} }{1.95L} \\\\M=0.38M[/tex]
Moreover, as the mass percent is computed as:
[tex]\% m=\frac{m_{KNO_3}}{m_{solution}} *100\%[/tex]
Thus, by using the given density of the solution, we obtain:
[tex]\% m=\frac{75.1g}{1.95L*\frac{1000mL}{1L}*\frac{1.05g}{1mL} } *100\%\\\\ \% m=3.67\%[/tex]
Regards.
Several groups of students are attempting to determine the density of a lead weight by various methods. Their data is shown in
the table. A handbook lists the density of lead as 11.3 g/mL.
Group 1
Group 2
Group 3
Measured density (g/mL), trial 1
11.5
11.5
10.9
Measured density (g/mL), trial 2
11.3
11.4
11.3
Measured density (g/mL), trial 3
11.1
11.4
11.1
Average density (g/mL)
11.3
11.4
11.1
Which group was most accurate?
Which group was most precise?
O Group 2
O Group 3
O Group 1
O Group 3
O Group 2
O Group 1
Answer:
accurate: Group 1precise: Group 2Explanation:
Accuracy is a measure of how close a measured value is to the true value. Here, we assume the handbook value (11.3) to be the true value. Group 1 arrived at this number, so must be considered to have made the most accurate measurement.
__
Usually, precision refers to the value of the least significant digit of the measurement. Here, all measurements were made to 3 significant digits, with the least digit being tenths. On that basis, no group can claim better precision than any other.
Another way to consider precision is to look at the variation in measured values. Group 2's values were the most consistent, having a range of 0.1 g/mL. Group 1's values had a range of 0.4 g/mL (from 11.1 to 11.5), and Group 3's values also ranged over 0.4 g/mL (from 10.9 to 11.3).
Because Group 2 had the most consistent readings, we award them the title of most precise.
Answer:
accurate: Group 1
precise: Group 2
Explanation:
Accuracy is a measure of how close a measured value is to the true value. Here, we assume the handbook value (11.3) to be the true value. Group 1 arrived at this number, so must be considered to have made the most accurate measurement.
What are the different forms of energy involved in stretching and releasing a rubber band? What other processes are similar?
Answer:
the answer is elastic potential energy to kinetic energy
Explanation:
A stretched rubber band contains potential energy (specifically called elastic potential energy because the material involved is elastic), which when released, the rubber band tries to return back to it's original shape and size. During the process of this return, the elastic potential energy is immediately converted to kinetic energy.
NOTE: Potential energy can be defined as the energy stored/present in a body at rest. It is usually as a result of the body's position or state. The potential energy stored in an elastic material is called elastic potential energy.
Kinetic energy can simply be described as the energy present in an object that is in motion.
One major process that is similar to the processes above is the mechanical energy, which is the energy involved in an object that has the ability to do work which in this case is a drawn elastic rubber that has the ability to "return" to it's initial state.
Describe the energy inputs and outputs for the campfire. Use the law of conservation of energy to construct a valid qualitative equation that includes all the input and output energies involved.
I did some fire simulation work recently where a small paper fire (think like half a ream of printer paper) was putting out 4000 watts, or about 5 horsepower. A large roaring campfire is going to be a few multiples of that depending on size, of course.
What is the difference between a volume that is delivered and a volume that is contained?
Answer:
When the graduation line denotes the volume contained in the calibrated vessel, the ware is marked “TC”. When the graduation line indicates the volume delivered from the vessel, the ware is marked “TD”.
Which of the following molecules is diamagnetic according to molecular orbital theory? A) N₂⁺ B) N₂⁻ C) CN D) CN⁻
Answer:
D) CN⁻
Explanation:
Hund's Rule of Maximum Multiplicity state that electrons go into degenerate orbitals of sub-levels (p,d, and f ) singly before pairing commences. Hund's rule is useful in determining the number of unpaired electrons in an atom. As such, it explains some magnetic properties of elements.
An element whose atoms or molecules contain unpaired electrons is paramagnetic. i.e., weakly attracted to substances in a magnetic field.
On the other hand, the element whose atoms or molecules are filled up with paired electrons is known as diamagnetic, i.e., not attracted by magnetic substances.
According to the molecular orbital theory, the diamagnetic molecule is CN⁻ because of the absence of unpaired electrons.
CN⁻ is diamagnetic according to molecular orbital theory.
Hund's Rule of Maximum Multiplicity
Before partnering, electrons enter deficient orbitals of sub-levels individually.
The Hund's rule may be used to calculate the number of unattached electrons in an atom. As a result, various magnetic characteristics of elements are explained.
A paramagnetic substance has unpaired electrons in its atoms or molecules. In a magnetic field, they are slightly attracted to substances.
According to the molecular orbital theory
Because there are no unattached electrons, the diamagnetic compound is CN⁻.
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Obtain a box of breakfast cereal and read the list of ingredients. What are four chemicals from the list
Options:
monoglycerides
cocamide DEA
folic acid
iron chromium ion
peroxide
lauryl glucoside
disodium phosphate
Answer and Explanation:
The added chemicals are:
monoglyceridesfolic acidirondisodium phophatesMonoglycerides are fats added for flavour. Folic cid and iron are vitamins added for nutritional value. disodium phosphate is a food additive for enhancing flavour.
The remaining ingredients are organic based.
Calculate how much 95% ethyl alcohol will be required to dissolve 0.3g of sulfanilamide at 78�C. Use the values 78 deg C: 180 mg/ml and 0 deg C: 10 mg/ml
Answer:
1.67mL of 95% ethyl alcohol are required to dissolve completely the sulfanilamide
Explanation:
Solubility is defined as the amount of substance that a determined amount of solvent can dissolve
As you can see, 95% ethyl alcohol at 78°C can dissolve 180mg of sulfanilamide per mililiter. That means solubility is 180mg/mL = 0.180g/mL.
As you want to dissolve 0.3g, you require:
0.3g * (1mL / 0.180g) =
1.67mL of 95% ethyl alcohol are required to dissolve completely the sulfanilamideThe value of the equilibrium constant for a reaction is 2.65 x 10-6 at 35° Calculate the value of LaTeX: \DeltaΔG°rxn.
Answer:
234
Explanation:
A certain chemical reaction releases 15.6/kJg of heat for each gram of reactant consumed. How can you calculate the heat produced by the consumption of 1.5kg of reactant? the math up. But don't do any of it. Just leave your answer as a math expression.
Answer:
The chemical reaction releases 23400 kilojoules due to 1.5 kg-reactant.
Explanation:
Given the amount of energy released due to reactant consumption, total energy ([tex]Q[/tex]), measured in kilojoules, is determined by the following expression:
[tex]Q = m\cdot L[/tex]
Where:
[tex]m[/tex] - Mass of reactant, measured in kilograms.
[tex]L[/tex] - Released heat ratio, measured in kilojoules per gram.
Given that [tex]m = 1500\,g[/tex] and [tex]L = 15.6\,\frac{kJ}{g}[/tex], the total energy released by chemical reaction is:
[tex]Q =(1500\,g)\cdot \left(15.6\,\frac{kJ}{g} \right)[/tex]
[tex]Q = 23400\,kJ[/tex]
The chemical reaction releases 23400 kilojoules due to 1.5 kg-reactant.