Thermo Review

Solve for the standard enthalpy of reaction (ΔH). Determine if the reaction is endothermic or exothermic.

• 40.7, endothermic

• -40.7, exothermic

• 106.4, endothermic

• -106.4, exothermic

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NGSS.HS-PS1-4

NGSS.HS-PS3-1

What kind of graph is this?

• endothermic
• exothermic

Tags

NGSS.HS-PS1-4

H₂ + 2 C + N₂ + 270.3 kJ --> 2 HCN
Is this reaction endothermic or exothermic?

• Endothermic 
• Exothermic

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

What does temperature measure?

• Heat
• ºC
• Kinetic Energy
• Thermal Energy

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NGSS.HS-PS1-5

NGSS.HS-PS3-4

What is the formula for calculating heat?

• q = mcΔT

• H = ΔH x moles

• H = ΔH x grams

• products - reactants

Tags

NGSS.HS-PS3-4

Consider the reaction: 2 H₂O + energy --> 2H₂ + O₂

• exothermic because releasing energy

• exothermic because absorbing energy

• endothermic because absorbing energy

• endothermic because releasing energy

Tags

NGSS.HS-PS1-4

• 1 J/g*C

• 250000 J/g*C

• 500 J/g*C

• 10 J/g*C

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NGSS.HS-PS3-1

NGSS.HS-PS3-4

A sample of iron receives 50 J of heat energy that raises the temperature of the iron 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

Tags

NGSS.HS-PS3-1

Experimental Set-up for Calories in a Chocolate Chip Cookie Students designed an experiment to determine the amount of calories in a chocolate chip cookie. A ring stand was used with a clean aluminum soda can hung from the ring that was partially filled with a known mass of water. A thermometer was placed inside the can so that it measured the temperature of the water but did not touch any part of the metal can. Once set-up was complete, an initial water temperature was taken. The cookie was then lit on fire and allowed to completely burn. A final temperature of the water was measured.

Refer to the experimental set-up for calories in a chocolate chip cookie. How does this experiment allow students to measure the calories in a cookie?

• The difference in masses before and after the cookie is burned is calculated, then converted into heat energy.

• Heat energy from the burning cookie is transferred to the water. The change in water temperature is used to calculate the heat energy from the cookie.

• Data from the amount of time for the cookie to burn and the temperature change are used to calculate the heat energy from the cookie.

• The cookie is burned until the water reaches a boiling temperature, then masses are compared to calculate the heat energy from the cookie.

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NGSS.HS-PS3-4

Between which points is the temperature of the substance remaining constant?

• A-B only

• A-B, C-D, and E-F

• B-C only

• B-C and D-E

Tags

NGSS.HS-PS3-4