Vocabulary
Energy caused by charged particles (electrons)
Electricity
What is always the direction of heat transfer?
high to low or low to high
high heat (energy) always moves to low heat (energy)
Identify each variable in this equation: q = mCΔT
q = joules
m = mass
C = specific heat
ΔT = change in temperature
The exploding bomb symbol indicates...
explosive or unstable substance
Energy can be described as the ability to:
do work or cause change
Energy stored in the chemical bonds between molecules.
Chemical Potential Energy
Is energy absorbed by the system or released by the system in an endothermic reaction?
Absorbed
CONVERT 575J to (cal)
1 Joule = 0.2390 calories
1 calorie = 4.184 Joules
137.425 cal
What does GHS stand for?
Globally Harmonized System
Turn 8.25 x 105 into a regular number.
825,000
the total change in energy (heat) for a reaction
Enthalpy
If your finger, touched an ice cube & the ice cube began to melt. What type of thermal reaction occured?
Exothermic Reaction
A chemical reaction releases 62.76 J of energy. How many calories are released?
1 Joule = 0.239
1 calorie (chem. calorie) = 4.184
14.999 or 15 cal
A flame over a circle symbol means...
the material is an oxidizer, meaning it releases oxygen & can make fires burn much hotter
Specific Heat: True or False
An element with a higher specific heat capacity requires more heat energy to raise the temperature, which also means it is faster to cool down.
FALSE
A substance that increases reaction rates by providing a lower energy path for the reactants
Catalyst
We know that ENTROPY is the measure of the disorder of a system, if a cup of liquid water froze into a solid ice cube - is the entropy increased or decreased? **THINK, what are the particles doing?**
Decreased
A snack provides 209.2 J of energy. How many Calories (big C) is that?
1 Joule = 4.184 calories
1 Calorie (big C) = 1,000 calories
209.2 ÷ 4.184 = 50 calories
50 cal ÷ 1000 = 0.050 C (big C calories)
You're heating a beaker of H2O on a hot plate, it starts to boil over causing sparks & a small fire - what do you do? List at least 3 steps.
safely remove the beaker from the hot plate, turn off the hot plate, grab the fire extinguisher, tell the teacher, pull the fire alarm (if it's out of control)
In a PE diagram, what variable is measured by the Y-axis.
What type of energy is defined as the kinetic energy of the atoms of a substance?
Chemical Energy or Thermal Energy
Thermal Energy
A student places 25 g of Chemical X into a small beaker. She then adds 50 mL of water and immediately places a thermometer into the mixture. Before the chemicals are combined, the mixture is 21°C. After several seconds, the temperature rises to 34°C. The student notices that the outside of the beaker feels warm. In which direction did thermal energy primarily flow?
system → surroundings
A 20g piece of copper has a specific heat of 0.385 J/g°C. How much heat energy is needed to raise its temperature from 20°C to 50°C?
231 J
You walk into chemistry and find your lab partner, "Billy Joe", "preparing" for today's experiment.
Billy J. is wearing flip-flops, has his long hair hanging over the lab bench, is eating a bag of Hot Cheetos, and has his backpack sitting in the middle of the aisle.
You notice that he has picked up a chemical bottle labeled with a flame pictogram and says:
"Don't worry, bro. I saw a TikTok where someone did this. I'm basically a scientist." He then decides to pour the chemical into another container without reading the label, gets some on the table, and says:
"It's fine. I'll just wipe it up with my hoodie."
Before you can stop him, he starts heating the chemical while pointing the test tube toward you.
Identify 6 lab safety violations.
open toe shoes, long hair not tied up, eating in the lab, backpack out in the aisle, not reading the chemical label, incorrectly cleaning up a spill, pointing a test tube at someone, heating an unknown chemical
Is burning wood a physical or chemical change?
Chemical change — New substances are produced when the wood burns.