AP Chemistry – Part 1 Brief

The number of _ in an atom defines which element it is.

protons

Atoms of the same element that differ in neutron number are called __.

isotopes

A _ is two or more atoms chemically joined and acting as a unit.

molecule

In chemistry, properties depend more on atomic __ than on which atoms are present.

arrangement/structure

The first step of the Scientific Method is to __ a phenomenon objectively.

observe

A tentative explanation formed after observation is called a __.

hypothesis

Data gathered with numbers (e.g., 18 m/s) are called __ data.

quantitative

A well-supported, widely accepted explanation of nature is termed a scientific __.

theory

The SI base unit for mass is the __.

kilogram (kg)

The SI base unit for temperature is the __.

kelvin (K)

The prefix ‘milli-’ (m) means multiply by 10 to the power.

−3

1 L is defined exactly as __ cm³.

1000

Mass is the amount of matter; weight is the __ acting on that mass.

gravitational force

When recording a measurement, the last digit written is the __ digit.

uncertain/estimated

Zeros between non-zero digits (captive zeros) are _ significant.

always

Leading zeros (e.g., 0.048) are __ significant.

never

Trailing zeros are significant only if a __ is present.

decimal point

Writing 3.00 × 10² g shows a measurement with __ significant figures.

three

For multiplication or division, the answer is rounded to the least number of __ in the inputs.

significant figures

For addition or subtraction, the result is rounded to the least precise __ place present.

decimal

During multi-step calculations, you should round only at the very __ of the problem.

end

A unit conversion factor equals __ , so multiplying by it does not change the value.

one

0 K represents a temperature at which particles have no __ energy.

kinetic

The exact difference between the Kelvin and Celsius scales is _ degrees.

273.15

The formula to convert Celsius to Fahrenheit is TF = (/) TC + 32.

9/5

Density is defined as mass divided by __.

volume

In chemistry, density commonly uses units of g/_ or g/mL.

cm³

Solids and liquids are called __ states because their particles are close together.

condensed

Liquids and gases are together known as __ states.

fluid

A __ substance has a uniform, definite composition.

pure

A mixture that is uniform at the atomic/molecular level is called a __.

solution (homogeneous mixture)

Physical changes do NOT alter the __ composition of a substance.

chemical

Separating a mixture by boiling off one component is called __.

distillation

Breaking water into hydrogen and oxygen is a __ change.

chemical

In sig-fig rules, the number 1500. (with a decimal) has significant figures.

four

The mantissa (front number) in scientific notation indicates the __ of significant figures.

number

A measurement written as .312 g is incorrect; it should be written with a leading __.

zero

The seven base SI units include meter, kilogram, second, kelvin, ampere, mole, and __ intensity.

luminous

The SI prefix ‘micro-’ uses the Greek letter μ and means 10 to the power.

−6

In dimensional analysis, units that appear in both numerator and denominator __.

cancel

A measurement tool’s smallest readable increment determines its __.

precision

Accuracy refers to closeness to the __ value.

true/accepted

When multiplying (1.342 m)(5.5 m), the answer must be given to __ significant figures.

two

Temperature changes are best expressed in the absolute unit __.

kelvin (K)

The absolute Fahrenheit scale, now archaic, is called __.

Rankine (°R)

Surface mass density uses the Greek letter __ as its symbol.

sigma (σ)

The proper symbol for density in STEM fields is the Greek letter __.

rho (ρ)

Matter that occupies space and has mass exists chiefly as solid, liquid, or __ on Earth.

gas