# Chemistry Chapter 1 and 2 2

## Terms

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mixed substances
a blend of two or more pure substances
Examples of mixed substances
Ex. air made up of mostly N2 and O2, gas, salt water, soup milk.
The substances that make up a mixture are called constituents.
Telling a mixture from an element or compound
Elements or compounds have 1 set of properties. Mixures retain the properties of each of its consituents.
Examples of telling a mixture from an element or compound
Salt water - it tastes salty and is a liquid like water
Fe(S) and S(s) - Fe is magnetic before and after mixing.
S (s) is smelly before and after mixing.
2) Telling amixture from an element or compound
The composition of a mixture is NOT fixed
EX I can add a lot or a little salt to water.
heterogeneous mixture
visibly different parts.
Examples of heterogeneous mixtures
Chicken noodle soup
an Olympic gold medal (they are only gold plated)
Scientific Notation
move the decimal so that only one nonzero number is to the left of the decimal.
If you move the decimal to the left the exponent is positive
If you move the decimal to the right the exponent is negative.
1,522,000,000,000
1.522 * 10âˆ§12
1,904,000,000
1.904 * 10âˆ§9
0.0075
7.5 * 10âˆ§-3
Multiplying Exponents
The first numbers are multplied while you add the exponent numbers
2.0*10âˆ§4* 3.0 * 10âˆ§-1
6.0 * 10âˆ§3
4.0 * 10âˆ§7 * 2.0 * 10âˆ§12
8.0 * 10âˆ§19
Dividing Exponents
The first numbers are divided while the exponent numbers get subtracted - It's numerator subtracted by the denominator.
9.0 * 10âˆ§4/2.0 * 10âˆ§8
9.0/2.0 = 4.5 * 10âˆ§4-8 = 4.5 * 10âˆ§-4
TI - 83 Version
9*10âˆ§4/(2.0*10âˆ§8) = 4.5 E-4 = 4.5 * 10âˆ§-4
6.0 * 10âˆ§-9/2.0 * 10âˆ§7
3.0 * 10âˆ§-16
Power of exponents
anything to the zero power is 1
10âˆ§0
1
2âˆ§0
1
Adding and subtracting numbers with exponents
The exponent base number is the same.
2.0 * 10âˆ§4 + 8.0 * 10âˆ§5
2.0 * 10âˆ§4 + 8.0*10âˆ§5
.20*10âˆ§4+1
.20 * 10âˆ§5 + 8.0 * 10âˆ§5
= 8.2 * 10âˆ§5
9.0 * 10âˆ§7 - 5.0 * 10âˆ§6
9.0 * 10âˆ§7 - .50 * 10âˆ§6
8.5*10âˆ§7
Percent Composition
pts from test/total pts * 100
mass of interest/total mass * 100
You have a 12g alloy made up of 2 g of Al, 3g of Fe and the rest Cu. What is the % by mass of Cu in the alloy
7/12g = 58.53 %

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