Thermochemistry

In an endothermic reaction the system is releasing energy.

• True
• False

Tags

NGSS.MS-PS1-4

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.  If the reaction is our system, is the system endothermic or exothermic?

• Exothermic
• Endothermic

Tags

NGSS.HS-PS1-4

Refer the the following question:
2N₂ + 3H₂ --> 2NH₃ + 46 kJ
How much energy would be produced if only 1 mol of nitrogen was reacted?

• 92 kJ
• 0.143 kJ
• 23 kJ
• 15 kJ

Tags

NGSS.HS-PS3-1

NGSS.HS-PS1-4

Using the equations below:

C_(s) + O_2(g) → CO_2(g) ∆H = –390 kJ

Mn_(s) + O_2(g) → MnO_2(s) ∆H = –520 kJ

what is ∆H (in kJ) for the following reaction?

MnO_2(s) + C_(s) → Mn_(s) + CO_2(g)

• 910

• 130

• -130

• -910

Tags

NGSS.HS-PS1-4

Consider the following equations.

Mg_(s) + O_2(g) → MgO_(s) ∆H = –602 kJ

H_2(g) + O_2(g) → H₂O_(g) ∆H = –242 kJ

What is the ∆H value (in kJ) for the following reaction?

MgO_(s) + H_2(g) → Mg_(s) + H₂O_(g)

• -844

• -360

• +360

• +844

Tags

NGSS.HS-PS1-4

A material was cooled from 100ºC to 40ºC.  What is the temperature change?

• 60ºC
• 40ºC
• -60ºC
• -40ºC

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

A 15.75-g piece of iron absorbs 1086.75 joules of heat energy, and its temperature changes from 25°C to 175°C.  Calculate the specific heat capacity of iron.    

• 0.46 J/gx^oC
• 1.654 J/gx^oC
• 2,567,446.875 J/gx^oC

Tags

NGSS.HS-PS3-1

The specific heat of aluminum is 0.21 J/g°C.  How much heat(Q) is released when a 10 g piece of aluminum foil is taken out of the oven and cools from 100° to 50°?

• 105 J
• 10.5 J
• 1.05 J

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-4

How many Joules of energy are required to make 100 grams of ice at 0 ^οC completely melt? The specific latent heat of fusion of ice is 334000 J/kg

• 200 J
• 400 J
• 33,400 J
• 2,000,000 J

Tags

NGSS.HS-PS3-1

How many joules are required to boil 75 grams of water?

• 25050J

• 169500J

• 31350J

• 10000J

Tags

NGSS.HS-PS3-1