Question

1. why does steam at 100°c cause more severe burns than liquid water at 100°c?

mark only one oval.
steam has lower density so it penetrates skin better
steam contains additional energy from the latent heat of vaporization
steam has a higher temperature than boiling water
steam moves faster than liquid water

1. a refrigerator removes heat from its interior and rejects heat to the room. if the refrigerator removes 1000 j from inside and the compressor does 300 j of work, how much heat is rejected to the room?

mark only one oval.
1300 j
1000 j
300 j
700 j

1. two materials with the same mass are heated with identical heat sources. material a reaches a higher temperature than material b. what can you conclude about their specific heat capacities?

mark only one oval.
both materials have the same specific heat capacity
material a has a higher specific heat capacity
material b has a higher specific heat capacity
cannot determine without knowing the final temperatures

Explanation:

24.

Steam at \(100^{\circ}C\) has additional energy from the latent heat of vaporization compared to liquid water at \(100^{\circ}C\). When steam condenses on the skin, it releases this latent heat, causing more severe burns.

Step1: Apply the first law of thermodynamics for refrigerators

The first - law of thermodynamics for a refrigerator is \(Q_{out}=Q_{in}+W\), where \(Q_{in}\) is the heat removed from the interior, \(W\) is the work done by the compressor, and \(Q_{out}\) is the heat rejected to the room.

Step2: Substitute the given values

Given \(Q_{in} = 1000\space J\) and \(W=300\space J\). Substituting into the formula \(Q_{out}=1000 + 300\)

Step1: Use the heat - transfer formula \(Q = mc\Delta T\)

Since the mass \(m\) is the same (\(m_A=m_B\)), the heat source is identical (\(Q_A = Q_B\)), and \(\Delta T=T - T_0\). We can rewrite the formula as \(c=\frac{Q}{m\Delta T}\)

Step2: Compare the specific heat capacities

If \(Q\) and \(m\) are constant, and \(\Delta T_A>\Delta T_B\) (because \(T_A>T_B\) assuming the same initial temperature \(T_0\)), then \(c_A=\frac{Q}{m\Delta T_A}\) and \(c_B=\frac{Q}{m\Delta T_B}\). Since \(\Delta T_A>\Delta T_B\), \(c_A < c_B\)

Answer:

Steam contains additional energy from the latent heat of vaporization

25.