Answer:
700 calories
Explanation:
Using the formula below:
Q = m × c × ∆T
Where;
Q = amount of heat required (calories)
m = mass of substance (g)
c = specific heat of substance (cal/g°C)
∆T = change in temperature (°C)
According to this question, the following information was provided;
Q = ?
m = 20g
c = 1.0 cal/g °C
∆T = 40°C - 5°C = 35°C
Using the formula; Q = m × c × ∆T
Q = 20 × 1 × 35
Q = 700 calories
Hence, 700 cal of heat energy is needed to raise 20 g of H2O from 5°C to 40°C.
You will need the equation PV = nRT
P = Pressure in kPa
V = Volume in L
n = moles
R = 8.314 (constant)
T = Temperature in Kelvin
First convert 2.5 atm into kPa:
2.5 X 101.3 = 253.25 kPa
Convert 125 Celsius into Kelvin:
125 + 273 = 398 K
Convert Gallons to Litres:
1.25 X 3.79 = 4.74 L
Plug your values into the equation to solve for n:
(253.25)(4.74) = n(8.314)(398)
n = (253.25)(4.74)/(8.314)(398)
n = 0.362 moles
Now use M = m/n to solve for the mass of O2
M = Molar Mass
M = mass
n= moles
32 = m/(0.362)
m = (32)(0.362)
m = 11.58g
A should be the products and D should be the reactants. So D should be the answer.
