Question

ObIel WiLll unt COl.. USSMS A certain chemical reaction releases 31.2 kJ/g of heat for each gram of reactant consumed. How can you calculate what mass of reactant will produce 1080. J of heat? Set the math up. But don't do any of it. Just leave your answer as a math expression. Also, be sure your answer includes all the correct unit symbols. mass X ? Explanation Check ducabon ARghtsserved T of Ue Phacy The I'm esc

Answer 1

Answer:

The expression to calculate the mass of the reactant is $m = \frac{1.080kJ}{31.2kJ/g}$

Explanation:

The amount of heat released is equal to the amount of heat released per gram of reactant times the mass of the reactant. To keep to coherence between units we need to transform 1,080 J to kJ. We do so with proportions:

$1,080J.\frac{1kJ}{10^{3}J } =1.080kJ$

Then,

$1.080kJ=31.2\frac{kJ}{g} .m\\m = \frac{1.080kJ}{31.2kJ/g}$

Answer 2

Answer:

1. The expression is: $m=\frac{E}{\Delta _rH}$

2. The computed mass is: $m=0.0346g$

Explanation:

Hello,

In this case, we know the so called enthalpy of reaction whose symbol and value is shown below:

$\Delta _rH=31.2\frac{kJ}{g}$

In addition, we know that the energy released by the involved reactant is:

$E=1080 J$

Therefore, the expression to compute the required mass, based on the given units is:

$m=\frac{E}{\Delta _rH}$

Finally, the computed mass turns out:

$m=\frac{1080J*\frac{1kJ}{1000J} }{31.2\frac{kJ}{g}} \\m=0.0346g$

Best regards.