Answer:
Explanation:
4NH₃ (g) + 3O₂ (g) ⇒ 2N₂ (g) + 6H₂ O(1)
Δ[tex]H_r={\sum}{ \Delta }H_f(\text{product})-{\sum}{ \Delta }H_f(\text{reactant})[/tex]
ΔH r =(2ΔH f(N 2 )+6ΔH f (H 2 O(l)))−(4ΔH f (NH 3 (g))+3ΔH f (O 2 (g)))
ΔH rex =[2×0+6×(−286)]−[4×(−46)+3×0]=−1716+186
ΔH rex =−1532kJ/mol
Thermodynamics is a branch of physical chemistry that studies heat and its effects and interactions. Governed by the four main laws, thermodynamics plays a huge role in physics and chemistry, and is also responsible for the law of conservation of energy, a fundamental rule in science.
The energy changes in two partial reactions are 225.3 kJ
and -432.0 kJ. The combined reaction is exothermic.
The combined reaction is exothermic , with the heat of reaction as -206.7 kJ
What is an Exothermic Reaction ?A reaction in which energy is liberated when reactants react to form products , The energy level of the reactant is more than that of the products.
The energy is liberated in the form of heat.
In the question it is given that
The energy changes in two partial reactions are 225.3 kJ and -432.0 kJ
The combined reaction is exothermic.
For the reaction to be exothermic the value of the heat of the reaction must be negative.
Summing the two energy changes will give us the heat of the combined reaction.
225.3 - 432.0
= -206.7 kJ
The combined reaction is exothermic , with the heat of reaction as -206.7 kJ.
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What is the advantage of using the electromagnetic spectrum model?
It helps compare frequencies of light.
It helps change the wavelengths of light.
The color of light waves can be changed using the model.
The intensities of light waves can be changed using the model.
Answer:
It helps compare frequencies of light.
Explanation: Hope it helps you :)))))
Have a good day.
Answer: A: It helps compare frequencies of light.
Explanation:
A solution of the ionic salt
NaCI would have
pH.
an acidic
a basic
a neutral
Answer:
Neutral
Explanation:
NaCl aqueous solution is formed by NaOH and HCl.
NaOH is a base and HCl is an acid, so they go through neutralization process forming a neutral salt and water.
8. (02.04 MC)
The partial electron configuration of an atom with 14 electrons is shown.
1s²2s²2p63s²x
Which of the following does X represent? (3 points)
2d²
3s²
3p²
4s²
E
Answer:
3p^2
Explanation:
after filling 3s^2 only two electrons left out of 14 so the next sub shell is 3p therefore ,X represents 3p^2
A student didn't notice that her pipette tip was broken. She used the pipette properly but it consistently delivered 4.70 cm³ of vinegar instead of the desired 5.00 cm³. How would the percent by mass results obtained have been affected? Explain your answer.
The mass % will be affected by 0.25%.
What is mass percentage ?Mass Percentage is defined as the grams of solute per gram of solution , multiplied by 100%
It is given that
She used the pipette properly but it consistently delivered 4.70 cm³ of vinegar instead of the desired 5.00 cm³.
Mass Percentage affected = ?
Mass is directly proportional to the volume
For calculating ratios of the same compound the density can be neglected
the density of vinegar is 1.05 gm/cm³
mass for 5cm³= 5*1.05 = 5.25gm
mass for 4.75 cm³ = 4.9875 gm
for 100 gm solution
mass% expected = 5.25* 100/100 = 5.25%
mass % (actual) = 4.9875 / (100-0.2625) = 5%
Therefore the mass % will be affected by 0.25%.
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Which statement about entropy is correct? - Entropy is sometimes described as the degree of randomness in a system. - solids are the state of matter with the most entropy. - entropy is a force of nature like gravity. - warm molecules have less entropy then cold molecules.
Answer: Entropy is sometimes described as the degree of randomness in a system.
does hot ice have to be cold or hot?
Answer:
hot
Explanation:
You'll need to boil the solution, though, to reduce the amount of water so that it is concentrated enough to form crystals. Cook your solution over low to medium heat for about an hour. You want to reduce it down to 1 cup or less.
Chemistry B Semester Exam
An unknown substance has a boiling point of 174°C. Which statement is true about this unknown substance? (1 point)
-It has a lower boiling point than water, and it likely has stronger electrostatic forces between its molecules
than water.
-It has a higher boiling point than water, and it likely has stronger electrostatic forces between its molecules
than water.
-It has a lower boiling point than water, and it likely has weaker electrostatic forces between its molecules
than water.
-It has a higher boiling point than water, and it likely has weaker electrostatic forces between its molecules
than water.
Answer:
See below
Explanation:
Boiling point of water is 100 C
this substance is higher boiling point and the molecules are likely with higher e-static forces
The unknown substance has a higher boiling point than water, and it has stronger electrostatic forces between its molecules than water. Therefore, option B is correct.
Boiling point is a measure of the temperature at which a substance changes from a liquid to a gas phase. Substances with higher boiling points generally have stronger intermolecular forces, such as hydrogen bonding or stronger dipole-dipole interactions.
Since the boiling point of the unknown substance is higher than that of water (which boils at 100°C), it suggests that the unknown substance likely has stronger electrostatic forces between its molecules compared to water.
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SOUND ENERGY :SCIENCE:
If you have A B C and D 4cups and A has nothing A is control Because the pitch is high but why is it important to have control
Answer:
As the amplitude of the sound wave increases, the intensity of the sound increases. Sounds with higher intensities are perceived to be louder. Relative sound intensities are often given in units named decibels (dB).
Explanation:
What do the little numbers (subscripts) next to the lower right of each letter mean in the C₂H₄O₂?
Answer:
It represents the number of atoms of that particular element present in the compound. In C₂H₄O₂ there are 2 Carbon atoms, 4 Hydrogen atoms and 2 Oxygen atoms.
A certain atom has 22 protons and 19 electrons. This atom loses an electron. The net charge on the atom is now 4+. If this same atom with 22 protons and 19 electrons were to gain 3 electrons, the net charge on the atom would be
Answer: 0
Explanation:
If 3 electrons were to be gained, then the number of protons would equal the number of electrons.
PLEASE HELP!
The vapor pressure of benzene at 25 °C is 95.1 mm Hg and of toluene 28.4 mm Hg. The mass fractions of benzene and toluene in a solution are 0.5.
a) Calculate the partial pressure of benzene and toluene above the solution.
b) Calculate the total vapor pressure above the solution.
c) Calculate the vapor composition above the solution.
Benzene be B
Toluene be T
We have made then one lettered to make things easier
[tex]\sf P^0_B=95.1mmHg,P^0_T=28.4mmHg[/tex][tex]\sf x_B=x_T=0.5[/tex][tex]\\ \rm\Rrightarrow \dfrac{P^0_B-P_B}{P^0_B}=x_B[/tex]
[tex]\\ \rm\Rrightarrow 95.1-P_B=95.(0.5)[/tex]
[tex]\\ \rm\Rrightarrow 95.1-P_B=47.55[/tex]
[tex]\\ \rm\Rrightarrow P_B=47.55mmHg[/tex]
And
[tex]\\ \rm\Rrightarrow \dfrac{P^0_T-P_T}{P^0_T}=x_T[/tex]
[tex]\\ \rm\Rrightarrow 28.4-P_T=28.4(0.5)[/tex]
[tex]\\ \rm\Rrightarrow P_T=14.2mmHg[/tex]
Total vapour pressure
28.4+95.1123.6mmHgA sample of gas is collected in a flask with a volume of 267 mL at a pressure of 771 mmHg and a temperature of 21C. If the mass of the gas is 1.05 g, what is the molar mass of the gas?
Answer:
M=93.5g/mol
Explanation:
I did this in class and it was a review. :)
What is the mass of a cube that has a density of 45g/ml and a volume of 15 ml?
Answer:
675g
Explanation:
The equation that relates mass, density and volume is:
Density = mass ÷ volume
By rearranging the equation we can find the mass of the cube.
Mass = density × volume
Mass = 45 × 15
∴ Mass = 675 grams
A gas occupies 4.31 liters at a pressure of 0.755 atm. Determine the Temperature
A gas that occupies 4.31 litres at a pressure of 0.755 atm will have a temperature of 39.58°C. Details about temperature can be found below.
How to calculate temperature?The temperature of a gas can be calculated using the following formula:
PV = nRT
Where;
P = pressureV = volumen = number of molesR = gas law constantT = temperature0.755 × 4.31 = 1 × 0.0821 × T
3.25 = 0.0821T
T = 3.25 ÷ 0.0821
T = 39.58°C
Therefore, a gas that occupies 4.31 litres at a pressure of 0.755 atm will have a temperature of 39.58°C.
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A 50.0 mL sample of gas at 20.0 atm of pressure is compressed to 40.0 atm of pressure at constant temperature. What is the new volume?
Answer:
20(50) = 40(V₂)
⇒1000 = 40V₂
⇒V₂ = 1000/40
⇒ V₂ = 25 mL
Explanation:
Answer:
25.0 mL
Explanation:
I took the test and got it right :)
Energy and Enthalpy Changes, Heat and Work -- Monatomic Ideal Gas dynamically generated plot 2.00-mol of a monatomic ideal gas goes from State A to State D via the path A→B→C→D: State A PA=11.0atm, VA=12.50L State B PB=11.0atm, VB=7.00L State C PC=25.0atm, VC=7.00L State D PD=25.0atm, VD=20.50L Assume that the external pressure is constant during each step and equals the final pressure of the gas for that step. Calculate q for this process. q = 1pts Tries 0/6 Calculate w for this process. w = -902 J Use w = -PΔV and sum over the individual steps. Check that you have the correct energy units and be sure you have the sign right (w is defined as the work done ON THE SYSTEM). 1pts Incorrect. Tries 4/6 Previous Tries Calculate ΔE for this process ΔE = 1pts Tries 0/6 Calculate ΔH for this process. ΔH = 1pts
(a) The heat generated in the process is 28 kJ.
(b) The work done in the process is determined as -28 kJ.
(c) The change in the internal energy is 0.
Heat of the isothermal compression
The heat generated in the process is negative done in the process.
W = -PΔV
W = -P(V₂ - V₁)
From A to BW = -P(VB - VA)
W = -11(7 - 12.5)
W = 60.5 L.atm = 60.5 x 101.325 J/L.atm = 6,130.16 J
From C to DW = -25(20.5 - 7)
W = -337.5 L.atm = -34,197.18 J
Total work , w = -34,197.18 J + 6,130.16 J = -28 kJ
q = - w
q = 28 kJ
Change in internal energyΔE = q + w
ΔE = 28 kJ - 28 kJ = 0
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What is the molality of this solution of table sugar in water?
The molality of the sugar solution is 0.034 mol/kg.
The molality and molarity of a chemical solution are equivalent for aqueous solutions of covalent molecules, such as sugar.
Question 4 of 10
Which statement best describes how scientists and engineers work together
in the research and development cycle?
OA. Scientists develop a theory, and then engineers perform
experiments to verify its accuracy.
B. Engineers do experiments to answer questions about nature, and
then scientists use the results to create a new technology.
OC. Scientists make designs based on engineering knowledge and
then make it available for public use.
D. Engineers develop a new technology, and then scientists use it to
make a new discovery.
Answer: Scientists make designs based on engineering knowledge and
then make it available for public use.
What happens if i don’t pass the chemistry regent?
Answer:
You will typically get another chance to retake the exam
Answer:
well you either have a chance to retake the test if your teacher or just not let you take it at all. you have to pass 4 regents test including chemistry in order to get a regent diploma. so you can either retake or it you just failed it.
what is the speed of light?can a object move in speed of light?
Answer:
The speed of light is the speed at which light travels. No, an object cannot move at the speed of light.
Explanation:
The speed of light is 186,000 miles per second. An object with mass cannot move at the speed of light since it would take an infinite amount of energy to achieve that velocity, since only massless particles can travel at the speed of light. Also, you would have to factor in air friction, meaning even if an object were to reach such high speeds, it would instantly disintegrate.
determine the number of gram of gas produced when 4.66 mole of water produced from the complete combustion of butane
.we can read the chemical preparation of the reaction as: "4 g of hydrogen react with 32 g of oxygen to give 36 g of water". :)
The food you eat can be broken into three main groups: _____, _____, and _____.
1 carbohydrates, fats, and vitamins
2 proteins, fats, and minerals
3 carbohydrates, fats, and proteins
4 proteins, vitamins, and minerals please help :)
Answer:
carbonhydrates, fats and ptoteins
Answer:3 carbohydrates, fats, and proteins
Explanation:
So I’m in 6th grade and this is a chart. I need the # of molecules, # of atoms in each element and the total # of atoms 2H₂SO
Answer:
1.) 2 molecules
2.) 4 H atoms, 2 S atoms, 2 O atoms
3.) 8 total atoms
Explanation:
1.) 2 H₂SO
--------> The molecule is all of the elements bonded together (H₂SO). Because there is a coefficient of 2 in front of the molecule, this means that there are 2 molecules present.
2.) 2 H₂S₁O₁
---------> The number of atoms of each element is determined by the subscripts and the coefficients. In one molecule, there is one oxygen, one sulfur, and 2 hydrogen atoms (denoted by subscripts). Because there are two molecules, these values are doubled.
3.)
--------> The total number of atoms is calculated by adding the number of atoms of each element. If between 2 molecules there are 4 hydrogens, 2 sulfurs, and 2 oxygens, combined there would be a total of 8 atoms.
How many moles of nitric acid are present in 50.0 g?
Answer:
3150.5g
Explanation:
1 mole of nitric acid weighs 63.01g
so i did 63.01g times 50.0g which equals 3150.5g
g= Grams
Hope This Helped
Answer:
0.79 moles
Explanation:
Formula :
Number of moles = Weight of substance / molecular mass
=============================================================
Here :
⇒ Weight of HNO₃ = 50 g
⇒ Molecular mass = 63 g
============================================================
Solving :
⇒ Number of moles = 50/63
⇒ Number of moles = 0.79 moles
What is the source of the forces that move the tectonic plates along this plate
boundary?
A. Differences in density between two different types of oceanic
crust
OB. Convection currents in the mantle
C. Convection cur nts in the ocean
D. Differences in density between oceanic crust and continental crust
The source of the forces that move the tectonic plates along this plate
boundary is the convection current in the mantle. Hence, the correct
option in option (B)
What are Tectonic plates ?Tectonic plates refers to the Spheres that are found in the uppermost Mantle of the Earth .
The Tectonic plates are also called the Litosphere .
The Motion of the Plates about the axis causes the Tectonic demarcations which are Know as the
Convergent
Divergent
Transform
Now these Plate are formed by the Convection of Currents in the Earths's Mantle
That is, the Dynamics of Current in and around the Earths Mantle brings about the tectonic plates
Hence the the correct option in option (B)
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Convection currents in the mantle is the source of the forces that move the tectonic plates along this plate boundary and is denoted as option B.
What is Convection?This is referred to the process of heat transfer in a fluid such as gases and liquids.
The convection currents in the mantle is responsible for the force present in the tectonic plates.
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a gas measures 725mm and 32C. what will be the temperature of the gas at 705mm?
Answer:
31°C
Explanation:
Using the ratio, we can find the temperature of the gas at 705mm.
725mm : 32°C
705mm : x
[ x is the temperature we have to find ]
Cross multiply the ratios.
725x = 705 × 32
725x = 22560
x = [tex]\frac{22560}{725}[/tex] = 31°C
describe another way in which human activities that benefit society can also cause environmental risk.
What volume of oxygen gas is needed for the complete combustion of 40.0 liters of hydrogen gas?
Answer:
2C2H6 + 7O2 ==> 4CO2 + 6H2O
When dealing with gases, it is possible to use liters and mols interchangeably.
So 4.00 L C2H6 x (7 mols O2/2 mols C2H6) = 4.00 x 7/2 = ? L O2
Explanation:
What information does the potential energy diagram reveal about a reaction?
A. It shows what the enthalpy of formation is for each molecule.
B. It shows the changes in kinetic energy of the molecules.
C. It shows what phase changes occurred during the reaction.
D. It shows whether the reaction is exothermic or endothermic.
Answer: It shows whether the reaction is exothermic or endothermic.
Explanation:
If the potential energy of the products is greater than that of the reactants, then the reaction is exothermic.If the potential energy of the reactants is greater than that of the products, then the reaction is endothermic.