30 questions
During an exothermic reaction, heat content in the surroundings increases because
heat energy is destroyed during reactions
the reaction absorbs heat energy
the energy contained in the reactants is lower then the products
the energy contained in the products is lower than the reactants
The diagram represents two solids and the temperature of each. What occurs when the two solids are placed in contact with each other?
Heat energy flows from solid A to solid B. Solid A decreases in temperature
Heat energy flows from solid A to solid B. Solid A increases in temperature
Heat energy flows from solid B to solid A. Solid B decreases in temperature.
Heat energy flows from solid B to solid A. Solid B increases in temperature.
The amount of heat energy required to change the temperature of 12 g of gold from 45°C to 15°C is -47 J. What is the specific heat capacity of gold?
0.13 J/(g°C)
17,000 J/(g°C)
1600 J/(g°C)
0.065 J/(g°C)
A cast iron skillet is used to fry bacon. For optimal frying, the pan must be heated to about 178 oC from a room temperature of 22.0 oC. It is known that 1.58 x 105 J of heat energy are absorbed by the pan to reach the desired temperature and the specific heat of iron is 0.450 J/g oC. What must the mass of the skillet be?
12.7 kg
2.25 kg
110 kg
1.97 kg
______________ is the average kinetic energy of particles.
Temperature
thermal rate
reaction rate
kinetic force
If kinetic energy increases, ____________ will also increase?
Temperature
acidity
basicity
A 24.0 gram sample of copper was heated from 25.0oC to 500.0oC, 4378J of heat were absorbed, what is the specific heat of copper?
.384
49909200
2.60
8.77
The specific heat(c) of copper is 0.39 J/g °C. What is the temperature change(∆t) when 100 Joules of heat(Q) is added to 20 grams?
12.82 °C
24.12°C
351 °C
Potential energy is stored energy.
True
False
If the enthalpy (ΔH) is negative the reaction is ____.
Endothermic
Exothermic
Neutral
what does c stand for?
heat capacity
specific heat
mass
temperature
Mass must always be in ________ for energy calculations.
kilograms
grams
joules
calories
What is the specific heat of water?
4.184 J/gC
1.00 cal/gC
All of the above
none of the above
What is the SI unit of heat and energy?
calorie
celsius
joule
The specific heat(c) of copper is 0.39 J/g °C. What is the temperature change(∆t) when 100 Joules of heat(Q) is added to 20 grams?
12.82 °C
24.12°C
351 °C
1 food calorie = _______ chemistry calories
1000
1
500
4.184
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.
What device is used to measure the amount of heat involved in a chemical reaction or physical process?
barometer
calorimeter
thermometer
The specific heat of a substance varies with the mass of a sample. True or False?
True
False
How do you calculate Enthalpy of a reaction?
ΔH = ΔHproducts - ΔHreactants
ΔT = q / mC
ΔG = ΔH -TΔS
E = mc2
Define the term Exothermic by picking the correct statements
Products have less energy than the reactants
ΔH is negative
ΔH is positive
Energy is given out to the surroundings (temperature goes up).
products have more energy than the reactants
Define Endothermic by picking the correct statements
ΔH is positive
Energy is taken in from the surroundings (temperature goes down).
Energy is given out to the surroundings (temperature goes up).
· Products have less energy than the reactants
products have more energy than the reactants
5.0 g of copper was heated from 20°C to 80°C. How much energy was used to heat Cu? (Specific heat capacity of Cu is 0.092 J/g °C)
27.6 J
36.8J
9.2 J
0.91 J