6.4-6.5 Quiz Flashcards
How is the energy between the system and the surrounding connected according to the first law of thermodynamics?
The first law of thermodynamics states that energy cannot be created or lost, only transferred. So energy of the system= - energy of the surroundings.
The negative side will go on whatever is LOSING energy
If the temperature of a solution increases, what happens to the thermal energy of the dissolution process?
What type of reaction is this?
The thermal energy was released and the reaction is exothermic.
If the temperature of a solution decreases, what happens to the thermal energy of the dissolution process?
What type of reaction is this?
The thermal energy was absorbed and the reaction is endothermic.
Q
Quantity of heat
The transfer of thermal energy between two bodies that are at different temperatures, from an object at a higher temperature to one that is colder
Change in temperature equation
Final temperature minus initial temperature
Specific Heat Capacity
Amount of energy needed to raise the temperature of one gram of a substance by one ° Celsius.
Water specific heat
4.184 J/ grams times celsius
How many joules are in a kilojoule?
1000
Calorimeter
Measures the amount of heat transferred during a reaction. Stops the transfer of heat between the inside of the calorimeter and surroundings
When specific heat is higher, the change in temperature is __________?
Lower
Heating a system results in the system having ______ energy and why?
greater energy because energy is flowing into the system
Cooling a system results in the system having _________ energy and why?
less energy because energy is leaving the system.
If an equation is talking about a change in temperature, what are they referencing?
SURROUNDINGS
If you are asked what provides more energy per gram?
It would be joules divided by grams
When finding the heat of a solution and you get to the mass what do you do?
The mass is additive, so add all parts of the solution
When finding the heat of a solution mixed with water and you need a specific heat but don’t have one what do you do?
Assume that it is the water specific heat, 4.184]
When calculating heat how do you know if your final answer is positive or negative?
If your change in temperature is positive then the final answer is negative because the surroundings gained heat, so the system lost heat, so exothermic.
If your change in temperature is negative then the final answer is positive because the surroundings lost heat, so the system gained heat, so endothermic.
How do you solve this if you are given the specific heat capacity for all three: 15.0 grams of ice, liquid water and water vapor are all heated by 10.2 °C, which required the greatest
amount energy?
You do the specific heat of each divided by 15 grams, and whichever one is the largest number required the greatest energy.
If you are dealing with mL of water and you need it to be grams what do you do?
Assume the density of water is 1 g/mL so 155 mL is 155 g.
