Answer:
2.6 kJ/mol
Explanation:
Step 1: Given data
Standard enthalpy of vaporization of water (ΔH°): 40.7 kJ/molStandard entropy of vaporization of water (ΔS°): 109 J/mol.KAbsolute temperature (T): 350 KStandard Gibbs free energy of vaporization of water (ΔG°): ?Step 2: Calculate ΔG°
We can calculate ΔG° using the following expression.
ΔG° = ΔH° - T × ΔS°
ΔG° = 40.7 kJ/mol - 350 K × 0.109 kJ/mol.K
ΔG° = 2.6 kJ/mol
The change in Gibbs free energy, ΔG for the water is 2.55 KJ/mol
Data obtained from the questionFrom the question given above, the following data were obtained:
Standard enthalpy of vaporization of water (ΔH°) = 40.7 kJ/molStandard entropy of vaporization of water (ΔS°) = 109 J/Kmol = 109 / 1000 = 0.109 KJ/Kmol Absolute temperature (T) = 350 KStandard Gibbs free energy (ΔG°) =? How to determine the Gibbs free energy, ΔG°The Gibbs free energy, ΔG° can be obtained as illustrated below:
ΔG° = ΔH° – TΔS°
ΔG° = 40.7 – (350 × 0.109)
ΔG° = 40.7 – 38.15
ΔG° = 2.55 KJ/mol
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Which of the following is a description of an exothermic reaction?
A. releases heat
B. reactants have less enthalpy than the products
C. ∆H is positive
D. gets cold
A description of an exothermic reaction is it releases heat. The correct option is A.
What is an exothermic reaction?An exothermic reaction is a reaction in which heat is released into the atmosphere. In these reactions, less energy is needed to start the reaction and the energy is released when bonds are made in the products. Delta H is always negative in these reactions.
Energy is always given off when the reaction happened, in the form of heat and light. Examples are burning of wood, melting of ice, combustion, corrosion, etc.
Thus, the correct option is A. releases heat regarding a description of an exothermic reaction.
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Explain why CaCl2 is likely to have properties similar to those of CaBr2
Answer:
Because both CaCl2 and CaBr2 both contain elements (Chlorine and Bromine) from the same group (group 7)
Explanation:
Elements are placed into different groups in the periodic table. Elements in the same group are those that have the same number of valence electrons in their outermost shell and as a result will behave similar chemically i.e. will react with other elements in the same manner.
Chlorine and Bromine are two elements belonging to group 7 of the periodic table. They are called HALOGENS and they have seven valence electrons in their outermost shell. Hence, when they form a compound with Calcium, a group two element, these compounds (CaCl2 and CaBr2) will possess similar properties because they have elements that are from the same group (halogen group).
The compounds of [tex]\rm CaCl_2[/tex] and [tex]\rm CaBr_2[/tex] have similar chemical properties as they are constituted of elements belonging to the same group.
The compounds with the elements belonging to the same group have similar chemical properties. It has been given that the chemical properties of elements have been dependent on the number of valence electrons.
The given compounds have been calcium chloride and calcium bromide. The calcium has been the same cation in the compounds however, the anions are different.
The anion Cl and Br both belongs to group 17 and have 7 valence electrons. Thus, the compounds have been possessing similar chemical properties.
Thus, calcium chloride and calcium bromide are more likely to have similar chemical properties as they have elements belonging to the same group.
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How many moles of calcium are in 5.82g of calcium?
Answer:
0.024951344877489 mole.
Explanation:
y
Which of the following represents the least number of molecules?
(a) 20.0 g of H2O (18.02 g/mol)
(b) 77.0 g of CH4 (16.06 g/mol)
(c) 68.0 g of CaH2 (42.09 g/mol)
(d) 100.0 g of N2O (44.02 g/mol)
(e) 84.0 g of HF (20.01 g/mol)
Answer:
A ; 20g of water has the least number of molecules
Explanation:
Here, we want to know which of the options represent the least number of molecules;
To calculate this, we are going to first calculate the number of moles using the formula below;
Number of moles = mass/molar mass
Then from the number of moles, we can calculate the number of molecules by multiplying the number of moles by 6.02 * 10^23 molecules
Let’s proceed;
a. That will be 20/18.02 = 1.1099 moles
1.1099 * 6.02 * 10^23 = 6.68 * 10^23 molecules
b. That will be 77/16.06 = 4.8 moles
4.8 * 6.02 * 10^23 = 2.89 * 10*24 molecules
c. That will be 68/42.09 = 1.62 moles
1.62 * 6.02 * 10^23 = 9.73 * 10^23 molecules
d. That will be 100/44.02 = 2.27 moles
2.27 * 6.02 * 10^23 = 1.37 * 10^24 molecules
e. That will be = 84/20.01 = 4.2 moles
4.2 * 6.02 * 10^23 = 2.53 * 10^24 molecules
From all the values obtained, the lowest is 20g of water
What is the average pressure exerted by the molecules on the walls of the container?
Answer:
This question appears to be incomplete
Explanation:
However, we know that one of the kinetic theories of gases is that gas molecules collide with one another and against the walls of the container (in which they are stored); hence exerting there pressure on the walls of this container.
Ideal gases are the most suitable for this theory because it's molecules are far apart and do not exert any attractive forces towards one another; hence it's molecules move "undisturbed" or "freely". For ideal gases, the average pressure exerted by by the gas molecules on the walls of the container can be calculated as
PV = nRT
Where P = pressure (in atmosphere, atm or kilopascal, KPa or millimeter mercury, mmHg)
V = volume (in liters)
n = number of molecules
R = ideal gas constant (8.3145 J·mol⁻¹·K⁻¹)
T = temperature (in kelvin)