Units and Conversions for Energy
What is the standard unit used for energy?
Joule
What is the difference between exothermic and endothermic?
Exothermic - releases heat
Endothermic - absorbs heat
In exothermic and endothermic reactions, is the energy of the reaction going to be positive or negative?
Exothermic - negative
Endothermic - positive
What are the factors that affect rate of reaction?
concentration, heat, and catalysts
What is the ideal gas law equation?
PV = nRT
How much energy does carbs vs proteins vs fat provide?
Carbs = 4 Cal/g
Protein = 4 Cal/g
Fat = 9 Cal/g
Is heat on the product or reactant side for an exothermic reaction?
Product
How do you find the energy of the reaction?
energy of bonds broken - energy of bonds formed
For the equation 2 H2 + O2 -> 2 H2O, what way will it shift if you add a catalyst?
no shift
If you have a 250 mL closed container of 3 moles of hydrogen with a pressure of 2,763,360 torr and 30 degrees celcius, what are the numbers in the correct units for our ideal gas law equation?
250 mL = 0.25 L
2,763,360 torr = 3636 atm
30 degrees celcius = 303 K
3 mol = 3 mol
If a bar has 650 Calories, how much energy is that in Joules?
2,719,600 Joules
What kind of reaction goes faster?
exothermic
How do you find the activation energy?
The difference between the peak energy and the reactants.
For the equation 2 H2 + O2 -> 2 H2O, what way will it shift if you add H2?
right
If you increase the volume to 0.5 L, but keep everything else constant, what is the new pressure? Is it going to increase or decrease and why?
1818 atm
Decrease because when you increase the volume the molecules will not collide as much.
If 300 Calories come from carbohydrates, how many grams is in a serving?
75 grams
For exothermic is energy going to go down or up?
(Ex. reactants are at 100 are you going to go up to 150 or down to 50)
Down (ex. down to 50)
What is the heat of reaction for 2 H2 + O2 -> 2 H2O? Is it exothermic or endothermic?
H-H 436
O=O 498
H-O 464
1370 - 1856 = -486 kJ/mol
exothermic = energy lost
For the equation 2 H2 + O2 -> 2 H2O, what way will it shift if you remove heat?
right
If add 4 moles to the starting values, what would the new temperature be?
129.86 K
Calculate the total Calories for one bar using the grams of total fat, total carbs, and protein.
Total fat = 10 grams
Total carbs = 50 grams
Total protein = 15 grams
Total fat = 90 grams
Total carbs = 200 grams
Total protein = 60 grams
Total Calories = 350 Calories
For endothermic is energy going to go down or up?
(Ex. reactants are at 100 are you going to go up to 150 or down to 50)
up (ex. up to 150)
What is the activation energy of an endothermic reaction whose reactants are at 300, peak at 400, and products are at 50? How about energy of reaction?
Activation energy = 100
Energy of reaction = 250
For the equation 2 H2 + O2 -> 2 H2O, what way will it shift if you remove O2?
left
If you increase the tempurature to 400K and keep the rest of the starting values, what would the new pressure be? Would we expect it to increase or decrease?
4800 atm
Increased because more heat means more energy, meaning the molecules will collide more