<h2>
Answer:</h2><h2>
The percentage of the family’s total annual electricity that is used to run the two air conditioners for the three summer months = 19.4 %</h2>
Explanation:
Average electricity consumed per month = 900 kWh
The family cools their house for three months during the summer with two window-unit air conditioners
The power consumed by one window-unit air conditioners = 350 kWh
The power consumed by two window-unit air conditioners = 350(2) = 700 kWh
Power consumed for two air conditioners for the three summer months = 700 (3) = 2100 kWh
Total power consumed for 1 year = 900 (12) = 10800kWh
The percentage of the family’s total annual electricity that is used to run the two air conditioners for the three summer months = 
= 19.4 %
Answer:
Atomic number = 10
Mass number = 20
Explanation:
Mass number = neutrons+protons
Mass number = 10+10 = 20
To find the number of moles of gas we can use the ideal gas law equation, we dont need to use the mass of gas given as we only have to find the number of moles
PV = nRT
P - pressure - 300.0 kPa
V - volume - 25.0 x 10⁻³ m³
n - number of moles
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature in Kelvin - 27 °C + 273 = 300 K
substituting these values in the equation
300.0 kPa x 25.0 x 10⁻³ m³ = n x 8.314 Jmol⁻¹K⁻¹ x 300 K
n = 3.01 mol
number of mols of gas - 3.01 mol
Answer:
the mole fraction of Gas B is xB= 0.612 (61.2%)
Explanation:
Assuming ideal gas behaviour of A and B, then
pA*V=nA*R*T
pB*V=nB*R*T
where
V= volume = 10 L
T= temperature= 25°C= 298 K
pA and pB= partial pressures of A and B respectively = 5 atm and 7.89 atm
R= ideal gas constant = 0.082 atm*L/(mol*K)
therefore
nA= (pA*V)/(R*T) = 5 atm* 10 L /(0.082 atm*L/(mol*K) * 298 K) = 2.04 mole
nB= (pB*V)/(R*T) = 7.89 atm* 10 L /(0.082 atm*L/(mol*K) * 298 K) = 3.22 mole
therefore the total number of moles is
n = nA +nB= 2.04 mole + 3.22 mole = 5.26 mole
the mole fraction of Gas B is then
xB= nB/n= 3.22 mole/5.26 mole = 0.612
xB= 0.612
Note
another way to obtain it is through Dalton's law
P=pB*xB , P = pA+pB → xB = pB/(pA+pB) = 7.69 atm/( 5 atm + 7.89 atm) = 0.612
570/8.5=67.0 58... you only have to take the natural part, si the answer is 67 students
