Question

it requires 350 joules to raise a certain amount of a substance from 10.0°c to 30.0°c. the specific heat of the substance is 1.2 j/g°c. what is the mass of the substance? 12 g 15 g 18 g 30 g

Explanation:

1. First, identify the relevant formula:

• The heat - transfer formula is \(Q = mc\Delta T\), where \(Q\) is the heat energy transferred, \(m\) is the mass of the substance, \(c\) is the specific heat capacity, and \(\Delta T\) is the change in temperature.
• Given that \(Q = 350\ J\), \(c=1.2\ J/g^{\circ}C\), \(\Delta T=T_2 - T_1=30.0^{\circ}C - 10.0^{\circ}C = 20.0^{\circ}C\).

1. Then, solve for \(m\):

• Rearranging the formula \(Q = mc\Delta T\) for \(m\) gives \(m=\frac{Q}{c\Delta T}\).
• Substitute the given values: \(m=\frac{350\ J}{1.2\ J/g^{\circ}C\times20.0^{\circ}C}=\frac{350}{24}\ g\approx14.58\ g\approx15\ g\).

Answer:

15 g