Chem Unit 1

What is the sequence of the scientific method?

Observation → hypothesis → experiment → theory.

Define hypothesis in the context of the scientific method.

A testable explanation.

What can cause theories to be changed?

New evidence.

What is matter?

Anything that has mass and takes up space.

What is a physical property?

A property that can be observed without changing the substance.

Define chemical property.

The ability of a substance to react and form a new substance.

What is an intensive property?

A property that does not depend on the amount of substance (e.g., density, temperature).

What is an extensive property?

A property that does depend on the amount of substance (e.g., mass, volume).

What is the difference between physical change and chemical change?

Physical change involves no bonds being formed or broken, while chemical change involves bonds being formed or broken.

What is the SI unit for length?

Meter (m).

What is the SI unit for mass?

Kilogram (kg).

What is the SI unit for time?

Second (s).

What is the SI unit for temperature?

Kelvin (K).

What is the SI unit for amount?

Mole (mol).

What is dimensional analysis?

A method using conversion factors to cancel unwanted units.

How many particles are in 1 mole?

$6.0221 \times 10^{23}$ particles.

What is Avogadro's number?

$6.0221 \times 10^{23}\text{ mol}^{-1}$.

What is molar mass (M)?

The mass of 1 mole of a substance expressed in g/mol.

What is the formula for calculating moles?

$n = \frac{m}{M}$.

How do you calculate the number of particles (n)?

n = \frac{\text{#particles}}{N_A}.

What is the formula for concentration (C)?

$C = \frac{n}{V}$.

What is the formula for density (d)?

$d = \frac{m}{V}$.

What is the ideal gas law equation?

$PV = nRT$.

What is the standard temperature and pressure (STP)?

273.15 K and 100.000 kPa.

What volume does 1 mole of gas occupy at STP?

22.711 L.

What is the BIG IDEA related to chemistry conversions?

Most chemistry conversions go given → moles → wanted quantity.