CHE 103- Lecture 1

define chemistry:

• the study of matter (anything with mass and volume)

what are the three states of matter?

• solid

• liquid

• gas

is the shape of a solid definite or indefinite? what about volume?

• both are definite

is the shape of liquid definite or indefinite? what about volume?

• shape is not definite

• volume is definite

is the shape of a gas definite or indefinite? what about volume?

• indefinite shape and volume

• it is compressible

what is the difference between physical and chemical properties?

• physical properties are observable without changing chemical composition

• chemical properties are observed by changing chemical composition

physical changes can include:

• phase changes (state of matter), gas, liquid, or solid

• freezing points, melting points, boiling points, etc.

chemical changes include:

• a change in the chemical formula

what are elements?

• appear on the periodic table

• pure substance

• cannot be broken down by chemical means

what are compounds?

• composed of two or more DIFFERENT elements in fixed ratios

• can be broken down in their elements

define molecules:

• units of matter made of two or more atoms

heterogeneous:

• two or more pure substances that are not uniform in composition

• ex: blood, muscle

homogenous:

• two or more substances that are uniform in composition

• ex: IV solutions, soft drinks

mega:

• 10^6

kilo:

• 10³

deci:

10^-1

centi:

• 10^-2

milli:

• 10^-3

micro:

• 10^-6

nano:

• 10^-9

pico:

• 10^-12

list the metric units (length, mass, volume, time)

• meter

• gram

• liter

• second

what is the formula to convert celsius to fahrenheit?

• F= 9/5 C + 32

formula to convert celsius to kelvin?

• K= C+ 273

what kind of zeros are not significant (in sig figs)?

• leading zeros

• trailing zeros if there is no decimal point

which zeros are significant (in sig figs)?

• sandwiched zeros

• trailing zeros IF there is a decimal place

how do sig figs work if you are adding or subtracting?

• using the number with the least significant figures, AFTER the decimal point

how do sig figs work if multiplying or dividing?

• lowest sig figs is used

• NOT after decimal point

what is the formula for percent?

• part/whole * 100

what is the formula for density?

d = m/v

chemical or physical: bleach changes the color of a t-shirt

• chemical

chemical or physical: aluminum reacts with orange, liquid bromine

• chemical

chemical or physical: water vapor condense on a cold day

• physical

pure substance or solution: diamond

• pure substance

purse substance or solution: potassium dissolved in water

• solution