Unit 2 - Gases

Question 1

What is pressure?

Answer 1

Force per unit area

Question 2

How to have a greater pressure?

Answer 2

Decrease area, or increase temperature

When you have the same amount of force on a smaller area you increase the pressure.

(Ex lying on nails)

Question 3

What is the pressure of a gas?

Answer 3

When the molecules run into other substances (usually solids) causing pressure.

Question 4

What is the regular unit for pressure?

Answer 4

A kilo Pascal

Question 5

What is 1 Pa?

Answer 5

1 pa = 1 N/m2 (squared)

Question 6

What is atmospheric pressure’s definition?

Answer 6

Force per unit area exerted by the air on all objects.

Question 7

What is one atmospheric pressure?

In kpa, mm of Hg, and torr.

Answer 7

1 atmospheric pressure = 101.325 kPa

1 atm = 760 mm Hg

1 atm = 760 torr

Question 8

What are the 4 rules of Significant Digits?

Answer 8

all non zero digits are significant (1589 = four sig dig)

all trailing zeros are significant (1.0000 = five sig dig)

zeros between numbers are significant (0.303 = three sig digs)

leading zeros are not significant (0.353 = three sig digs)

Question 9

how to calculate sig digs with addition and subtraction?

Answer 9

round to the lowest amount of decimals in the equation

Question 10

How to calculate Sig Digs for multiplication

Answer 10

calculate the smallest amount of sig digs, then round to the nearest significant digit.

Question 11

What is the relationship between pressure and volume

Answer 11

It is an INVERSELY PROPORTIONAL RELATIONSHIP where pressure increases, volume decreases

and as pressure decreases, volume increases

This means you can switch them out for each other in formulas.

Question 12

What is Boyle’s Law?

Answer 12

PV = k ; where k is a constant and temp. Is the same

PV = PV

Question 13

What is the lowest possible temp??

What is 0K

Answer 13

-273.15 °C = 0 K

Question 14

What happens when gas is at absolute zero and doesn’t liquefy?

Answer 14

Its volume becomes zero.

Question 15

What happened to volume if the temp. increases?

What type of relationship is this?

Answer 15

The volume increases.

An direct relationship.

(Hot air balloon)

Question 16

What is Charles law?

What it it’s formula?

What is the temperature unit to use this formula?

Answer 16

As the temperature of a gas increases the volume increases if the pressure and chemical amount of gas remain constant.

V1 V2
=
T1. T2

Must use Kelvin (K).

Question 17

What variable are the X and Y axes?

Answer 17

The x-axis is manipulated variable and the y-axis is the responding variable

Question 18

What is STP?

Answer 18

Standard temperature and pressure.

0°C and 101.325kPa and 22.4L/mon

Question 19

What is SATP?

Answer 19

Standard ambient temperature and pressure.

25°C and 100 kPa and 24.8L/mol

Question 20

Which unit do you count sig digs for when it comes to temperature?

Answer 20

Only Kelvin.

Question 21

What is the law of combining volumes?

Answer 21

When gases combine at constant temperature and pressure, the volumes involved are always in the ratio of simple whole numbers

(The molar ratio in the balanced equation)

(No formula)

Question 22

Do you do sig digs for moles?

Answer 22

Yes!