Unit 3: Stoichiometry, limiting reactants, an Energy of Reactions

Molar Volume

the volume of a mol, only for gas

molar mass

the mass of a mol (g)

STP

standard temperature and pressure

standard temp

0 C 273K

standard pressure

1 atm

what to use if not specified at stp

pv=nrt

(not stoichiometrey) What to do when finding volume of a element in g

convert to mm, then mols, then use 22.4 (this is not stoichiometrey and is with 1 chemical and no balanced equations

stoichiometrey

1 specified number, convert using coefficients + L and units (2 chemicals, and an equation)

-q

heat lost, exothermic

+q

heat gained, endothermic

q units

J→ joules

Cp

specific heat capacity

Cp unit

J/g C

(triangle) temperature

change in temp

(triangle) temperature unit

C

What is a limiting reactant

the chemical we run out of

how to solve limiting reactants?

you know because it has 2 specified numbers and an equation, you have two problems, use the ratios and choose the smallest answer as your limiting reactant

0k

absolute zero, particles stop moving

food calories have a ___ c and science calories have a ____c

1. capital 2. lowercase

1 cal = ___J

4.1

1 food calorie = ____ science calories

1000

energy

ability to do work

difference between heat and temperature

heat is an energy transfer and temperature is a thermometer measured average of the speed of the particle

Endothermic

absorbs heat/light (cold)

exothermic

releases heat/light hot

system v. surroundings

at equilibrium it the system doesn’t appear to change, but it is a a molecular level. the surroundings is everything else

kinetic energy

movement

potential energy

stored in a certain position

what are the 2 types of energy and their abbreviations

ke: chemical and radiant/ pe: electric and nuclear

what drives every reaction and nonreaction

energy

What happens by the end of an explosion?

It goes into completion and bypasses equilibrium

What cannot happen to energy?

It cannot be created or destroyed

Entropy

Randomness and disorder or when things spread out

Enthalpy

Stored heat Or a measurement of it at a constant pressure

taco Bell principal

Everything in the universe must release it stored energy

Do metals have a large or small specific heat?

Small specific heat because They heat up fast and get cool fast when they heat food they expel heat into the food

What is the triangle T equation?

Temperature final minus temperature initial

What does CP stand for?

Specific heat capacity

Is water a good or bad heat sponge

It’s a great one

what can CP tell you about the heat?

How good the heat sponge is

How do you convert from joules to kilojoules?

You divide by 1000 or move the decimal three to the left

Is the m For mass cap or lowercase

Lowercase

What formula do we use to measure heat transfer?

Q plus or minus equals MC delta T

What is the trigger word for endothermic?

Absorbs

What is the trigger word for exothermic?

Released

Is endothermic positive or negative

Is exothermic positive or negative

Negative

Because the earth has a atmosphere, what does that mean?

It means that the earth has a moderate temperature

Which temperature is more moderate on the moon or on the Earth?

Earth

What specific heat capacity does liquid water tend to have?

A very high one, not the highest but high

How is the atmosphere responsible for keeping the heat so low

It traps heat in the atmosphere

Is water vapor double or half of liquid water? (J/g c)

Half

What is the most common greenhouse gas?

Water

Is carbon dioxide a greenhouse gas?

Yes, but it is not as common as water

Where does the energy get stored in molecules?

Within the bonds when they vibrate

Are molecule stronger if they have more or less bonds

More

Is a triple or double bond, one bond or multiple

One bond

What are greenhouse gases?

Greenhouse gases, are energy from the sun that attempt to break through the atmosphere. Greenhouse gases are energy from the sun that attempt to break through the atmosphere, which represents the glass of the greenhouse. Once it hits objects inside like rocks, plants or water, the objects, absorbed the heat, and the rest is reflected back at the atmosphere, but now the energy is lower and it does not have enough energy to make it out into the atmosphere. This is called a greenhouse, gas effect.

What does a oil or natural gas extraction always cause?

It causes a methane leak always

Is water vapor a greenhouse gas

Yes, because it stores heat

What is the easiest way to distinguish a greenhouse gas?

It stores heat and has a lot of bonds

What greenhouse gas is man-made?

Carbon dioxide

What greenhouse gas comes from nature

Water vapor mainly from the evaporating ocean

What is the volume of one mole?

22.4 L

When is molar volume used?

Only with gases

If something is not a STP, what do you use?

Pervnert

Why is it difficult for water to reach 100° easily?

Because we are not at sea level it is not an average day and we use an expensive thermometer

When you have two separate equal equations, what is normally going on?

Most of the time there is a heat transfer where one object loses heat annd the other object gains it.