Heat Transfer and Calorimetry

What would be the effect on the particles if more heat energy is REMOVED from the system?

• They would slow down
• They would stop moving
• They would speed up
• There would be no effect

Answer explanation

When heat energy is added to a substance, its particles gain kinetic energy and begin to move faster, resulting in increased vibration and collision rates between them; essentially, the more heat energy, the more the particles move, which is why temperature increases as a substance is heated.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

If two objects have different temperatures when they come in contact, heat will flow from the warmer object to the cooler one UNTIL ____________

• one reaches a temperature of zero

• they both have an equal temperature

• one runs out of energy

Answer explanation

When two objects have different temperatures, heat always flows from the object with the higher temperature to the object with the lower temperature; meaning heat transfer occurs from a warmer area to a cooler area until they reach thermal equilibrium (the same temperature).

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

A sample of iron receives 50.J of heat energy that raises the temperature of the iron by 25.0°C. If iron has a specific heat of 0.10 J/g°C, what is the mass of the iron sample?  

• 25g
• 30g
• 20g
• 50g

Answer explanation

Explanation; Q or heat flow, or thermal energy is measured using temperature change and calculated using the formula Q= mC ΔT., Where "m" is the mass, "C" is the specific heat capacity and delta T is the change in temperature. To determine the mass, we divide both sides by the product c×delta T

Tags

NGSS.MS-PS3-4

A reaction is performed in a beaker with a temperature probe recording the temperature changes of the reaction.  If the temperature began at 15.0 degrees Celsius and ended at 27.5 degrees Celsius. Is the reaction endothermic or exothermic?

• Exothermic
• Endothermic
• It is impossible to determine.

Answer explanation

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5

The equation 𝑞 = 𝑚𝐶Δ𝑇 us understand how heat moves in and out of different materials. In this equation, 𝑞 stands for the amount of (a)   energy involved. The letter 𝑚 represents the (b)   of the substance. 𝐶 is called the (c)   , which tells us how much heat is needed to raise the ​ (d)   of one unit of the substance by one degree. Finally, Δ𝑇 means the ​ (e)   in temperature. This equation helps us calculate how much heat energy is gained or lost when materials get warmer or cooler.

• A change in health

• A change in heat

• A change in height

• heat
• mass
• specific heat capacity
• temperature
• change

Answer explanation

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-3

NGSS.MS-PS3-4

Calorimetry is the measurement of the ___________

(Choose the best answer below.)

• transfer of heat into or out of a system (reaction/process)

• change in temperature

• amount of energy required to raise the temperature of 1 gram of the substance by 1°C.

• change in the mass of a substance throughout a reaction.

Answer explanation

Calorimetry specifically measures the transfer of heat into or out of a system during a reaction or process, making it the best answer. The other options describe related concepts but do not define calorimetry itself.

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5

• energy

• Change in temperature

• specific heat

• mass

Answer explanation

In the equation Q = mCpΔT, ΔT represents the change in temperature. It quantifies how much the temperature of a substance changes when heat is added or removed, making 'Change in temperature' the correct choice.

Tags

NGSS.MS-PS3-4

• energy

• Change in temperature

• specific heat

• mass

Answer explanation

In the equation Q = mCpΔT, Cp represents specific heat, which is the amount of heat required to change the temperature of a unit mass of a substance by one degree Celsius. Thus, the correct answer is specific heat.

Tags

NGSS.HS-PS3-4

Q = mCpΔT, m   is....

• energy

• Change in temperature

• specific heat

• mass

Answer explanation

In the equation Q = mCpΔT, 'm' represents mass, which is the quantity of matter in an object. The other options do not accurately describe 'm' in this context.

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-4

When a  piece of aluminum foil is taken out of the oven and cools from 125° C to 53°C, What is the change in temperature?

• -72°C

• +178°C

• -178°C

• +72°C

Answer explanation

The change in temperature is calculated by subtracting the final temperature from the initial temperature: 53°C - 125°C = -72°C. Thus, the correct answer is -72°C.

Tags

NGSS.MS-PS3-4