B. They are usually better conductors than nonmetals
Number 1 is the correct answer
Answer:
The system makes the transition from nonspontaneous to spontaneous at a temperature of 954.7 K.
Under 954.7 K the reaction is nonspontaneous; more than 954.7 K is the reaction spontaneous.
Explanation:
CH4(g) + 2H2O(g) ⇆ CO2(g) + 4H2(g)
CH4(g) H2O(g) CO2(g) H2(g) ΔH°f (kJ/mol): –74.87 –241.8 –393.5 0
ΔG°f (kJ/mol): –50.81 –228.6 –394.4 0
S°(J/K·mol): 186.1 188.8 213.7 130.7
ΔG<0 to be spontaneous
ΔG = ΔH- TΔS <0
ΔH = ∑nΔH(products) - ∑nΔH(reactant)
ΔH = (-393.5) - (–74.87 + 2*–241.8)
ΔH = 164.97 kJ = 164970 J
ΔS = ∑nΔS(products) - ∑nΔS(reactant)
ΔS = (213.7 + 4*130.7) - (186.1 + 2*188.8)
ΔS = 172.8 J
0 > 164970 J - T* 172.8 J
-164970 J > - T* 172.8 J
954.7< T
The system makes the transition from nonspontaneous to spontaneous at a temperature of 954.7 K.
Under 954.7 K the reaction is nonspontaneous; more than 954.7 K is the reaction spontaneous.
Answer:
25.2°C
Explanation:
Given parameters:
Energy applied to the water = 1000J
Mass of water = 50g
Final temperature = 30°C
Unknown:
Initial temperature = ?
Solution:
To solve this problem, we use the expression below:
H = m c Ф
H is the energy absorbed
m is the mass
c is the specific heat capacity
Ф is the change in temperature
1000 = 50 x 4.184 x (30 - initial temperature )
1000 = 209.2(30 - initial temperature)
4.78 = 30 - initial temperature
4.78 - 30 = - initial temperature
Initial temperature = 25.2°C
The molecular formula of the compound that has a percent composition of 38.7% carbon, 9.76% hydrogen, 51.5% oxygen is C2H6O2.
<h3>How to calculate molecular formula?</h3>
The molecular formula can be calculated from the empirical formula. The empirical formula of the compound is calculated as follows:
- C = 38.7% = 38.7g
- H = 9.76% = 9.76g
- O = 51.5% = 51.5g
Next, we convert the mass to moles by dividing by their atomic mass:
- C = 38.7 ÷ 12 = 3.23mol
- H = 9.76 ÷ 1 = 9.76mol
- O = 51.5÷ 16 = 3.22mol
Next, we divide by the smallest (3.22)
Hence, the empirical formula of the compound is CH3O
If the molar mass of the compound is 62g/mol;
(CH3O)n = 62
31n = 62
n = 2
(CH3O)2 = C2H6O2
Therefore, the molecular formula of the compound that has a percent composition of 38.7% carbon, 9.76% hydrogen, 51.5% oxygen is C2H6O2.
Learn more about molecular formula at: brainly.com/question/14425592