Q7. Hydrogen gas reacts with oxygen to water. form water. 483.5 kJ AH 2 H20g) O2

Question

Q7. Hydrogen gas reacts with oxygen to water. form water. 483.5 kJ AH 2 H20g) O2(g) 2 H2O(g) Determine the minimum mass of hydrogen ga required to produce 226 kJ of heat. c) 0.942 g a) 8.63 g d) 0.935 g b) 1.88 g os. Manganese reacts with hydrochloric acid to produce manganese chloride and hydrogen gas. Mn(s) 2 HCI ag) Mn aq) H20g) When 0.625 g Mn is combined with enough hydrochlo- ric acid to make 100.0 mL of solution in a coffee-cup calorimeter, all of the Mn reacts, raising the temperature of the solution from 23.5 oC to 28.8 °C. Find AHrxn for the reaction as written. (Assume that the specific heat capacity of the solution is 4.18 J/g °C and the density is 1.00 g/mL) a) 195 kJ c) 1.22 kJ d) 2.21 kJ

Explanation / Answer

Q7 Answer:-

Given data

Balanced reaction equation given

2H2(g)+ O2(g) ----> 2H2O(g)       ?H= -483.5 kJ

Minimum mass of H2 required to produce 226 kJ heat

According to the balanced reaction equation 2 mol of the H2 gas gives 483.5 kJ

Using this relation calculate moles of the H2 gas needed to produce 226 kJ heat

Following is the set up

(226 kJ * 2 mol H2 gas) / 483.5 kJ = 0.935 mol H2 gas

Now lets conver this moles of H2 gas to its mass

Mass = moles * molar mass

Molar mass of H2 gas = 2.02 g per mol

Lets use this molar mass in the above formula

Mass of H2 gas = 0.935 mol * 2.02 g per mol

                           = 1.88 g H2 gas

Mass of H2 gas needed to produce 226 kJ heat = 1.88 g

Therefore option

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