CHEM chapter 1 Matter & Measurement

College notes / prelecture / homework

micro 

10^-6  

milli                          

 0.001 

kilo                           

1000 

centi                        

 0.01

nano                        

 10^-9  

deci                          

0.1  

mega                         

1,000,000 

giga         

1,000,000,000 

1 = ? kilo = ? centi = ? mega = ? milli = ? deci = ? micro = ? nano 

0.001 / 100 / 0.000001 / 1,000 / 10 / 1,000,000 / 1,000,000,000

Match the dimension and metric unit: time

second

Match the dimension and metric unit: area

square meter

Match the dimension and metric unit: length

meter

Match the dimension and metric unit: volume

liter

Match the dimension and metric unit: mass

gram

Classify the following substances: tap water

homogeneous mixture

Classify the following substances: distilled water

pure compound

Classify the following substances: aluminum foil

pure element

Classify the following substances: wet sand

heterogenous mixture

Convert 0.0000000000510 to scientific notation.

5.10 x 10^-11

Convert 150,000,000,000 to scientific notation.

1.5 X 10^11

Determine the number of significant figures: 0.01050

4

Determine the number of significant figures: 56,000

2

Determine the number of significant figures: 1.23 x 10^4

3

Determine the number of significant figures: 1 inch = 2.54 cm

exact numbers

Determine the number of significant figures:: One water molecule has 2 hydrogen atoms

exact numbers

*less Sig Fig & round 12.20 - 1.459 =

10.74

*less Decimal place 12.00/5 =

2

1.500 x 4.000 + 4. = 

Hint: follow significant figure rules for each calculation

10.

Convert 0.13 liters to  milliliters. Do not use scientific notation or unit in the answer box.

0.13L * 1000m/ 1 L= 130mL

Convert 1,017 grams to kilogram. Do not use scientific notation or unit in the answer box.

1,017g * 1kg/ 1000g= 1.017kg

Convert 0.00033 g to micrograms. Do not use scientific notation or unit in the answer box.

0.00033g * 1,000,000ug/ 1g= 330ug

Jenny took temperature of the cake fresh from the oven as 191 Fahrenheit. The temperature is _____ C. Do not use scientific notation or unit in the answer box. Keep one decimal.

191- 32= 159 × 5= 795 / 9= 88.3 C

0.0078 millisecond equals _______ nanosecond. Do not use scientific notation or unit in the answer box. 

Hint: convert to basic unit (here as second) first

0.0078ms 10^-3s/ 1ms= 0.0000078s * 10^9ns/ 1s= 7800ns

A sample of 6.478 mL unknown liquid has a mass of 6.735 grams. What is the density of the liquid in g/mL?

d= 6.735g/ 6.478mL= 1.040g/mL

A lab technician needs 2.50 mL liquid solvent but there is only a scale to use. The density of this solvent is 2.43 g/mL. How many grams of solvent does he need to weigh to get 2.50 mL solvent? 

M= 2.43g/mL * 2.50mL= 6.08g

A sugar crystal (rock candy) weighs 22.7 grams. The density of sugar crystal is 1.55 g/cm³. What is the volume of this piece rock candy in milliliters?

V= 22.7g/ 1.55g/cm³ = 14.6 cm³

Matter:

mass, volume

Mass-

pure substance : element & compound ( dry ice CO2(s))

Volume -

mixture: homogeneous & heterogeneous (diamond ring, universe)

Atoms:

the tiny particles that make up all matter. 

• Helium gas (for blimp) is made up of Helium atoms.

Molecules:

In most substances, the atoms are joined together in units. 

• Liquid water is made up of water molecules (2 Hydrogen atoms + 1 Oxygen atoms)

Particles in a solid: packed close together

and are fixed in position though they may vibrate

• Incompressible

• retaining their shape and volume unless upon external pressure

• Unable to flow

Strong attractive forces in between atoms/molecules

Liquids, Particles are closely packed, but

they have some ability to move around

• Incompressible

• Able to flow, yet not to escape and expand to fill the container (not “antigravity”)

Strong Attractive forces among molecules

Gases, The particles have complete freedom

from each other (not sticky to each other)

• The particles are constantly flying around, bumping into each other and the container

• There is a lot of empty space between the particles (low density)

•  Compressible

• Able to flow and Fill space (“antigravity”)

Pure gas is transparent

Matter: Pure Substance

Constant Composition & Homogeneous

Mixture

Variable Composition, Pure substance

• Solid:

• Liquid:

• Gas:

1. Salt, Sugar, Dry ice, Copper, Diamond

2. Propane, distilled water (or Deionized water, DI water)

3. Helium gas (GOODYEAR blimp)

Elements:

Substances which can not be broken down into simpler substances by chemical reactions.

Compounds:

Most substances are chemical combinations of elements. ex Pure sugar, pure water

 Abundance:

 Hydrogen:

 Oxygen:

 Silicon:

1. percentage found in nature

2. most abundant in the universe

3. most abundant element (by mass) on earth and in the human body

4. abundant on earth surface

Heterogeneous:

matter that is non-uniform throughout, contains regions with different properties than other regions (gasoline mixed with water)

Homogeneous:

composition is uniform throughout, appears to be one thing (air, tap water)

What is a Measurement?

• Quantitative observation

• comparison to an agreed upon standard

Mass, gram

g

length, meter

m 1,000L 1m³

Volume, liter

L

time, seconds

s

temperature, kelvin

K

kilo = 1000 times base unit = _____

1 kg = 1000 g = 10^3 g

deci = 0.1 times the base unit = _____

1 dL = 0.1 L = 10^-1 L; 1 L = 10 dL

centi = 0.01 times the base unit = _____ 

1 cm = 0.01 m = 10^-2 m; 1 m = 100 cm

milli = 0.001 times the base unit = _____

1 mg = 0.001 g = 10^-3 g; 1 g = 1000 mg

micro = ______ times the base unit

1 m = 10^-6 m; 106 m = 1 m

nano = _______ times the base unit

1 nL = 10^-9L; 109 nL = 1 L

Length

• Two-dimensional distance an object covers

• SI unit: METER (abbreviation as m)

 About 3½ inches longer than a yard

Mass

• Amount of matter present in an object

• SI unit: gram and kilogram (kg)

• 1 kilogram ~ 2 lbs. 3 oz

Volume

• Amount of three-dimensional space occupied

• SI unit = cubic meter (m3)

• Commonly measure solid volume in cubic centimeters (cm3)

•  1 m^3 = 106 cm^3

• 1 cm^3 = 10-6 m^3 = 0.000001 m^3

Scientific Notation

Very Large vs. Very Small numbers:

The sun’s diameter is 1,392,000,000 m

Scientific Notation: 1.392 x 10^9 m

Sig. Fig.

The non-place-holding digits in a reported measurement 

• some zero’s are place holders (0.005010), NOT counted as significant figures.

What is Sig. Fig. for?

the range of values to expect for repeated measurements

• the more significant figures there are in a measurement, the smaller the range of values is, more precise.

12.30 cm: 4 sig. figs.

sig figs More sig figs =

more precision

Significant Figures (SF) vs.Decimal Places (DP)

1. All non-zero digits are significant ; 1.5 :

2. Interior zeros are significant ; 1.05 :

3. Zero: Only Trailing zeros are significant ; 1.050 : 4 SF, 3 DP

•  0.001050 :

1. 2 SF, 1 DP

2. 3 SF, 2 DP

3. 4 SF, 3 DP

   • 4 SF, 6 DP (Place-holding zero) = SN : 1.050 x 10^3

Exact numbers

1 pound = 16 ounces

 1 kilogram = 1,000 grams = 1,000,000 milligrams

 1 water molecule contains 2 hydrogen atoms

150:

 150. :

 1.50 x 10^2 :

1. ambiguous number

2. 3 SF

3. 3 SF

Sig. Fig. in Multiplication/Division

the fewest number of sig. fig.

Sig. Fig. in Addition/Subtraction:

the fewest number of decimal places

Sig. Fig. in Combined Calculations (PEMDAS)

conversion factor

Temperature:

measure of the average kinetic energy of the molecules in a sample

• a higher temperature means a larger average kinetic energy

Celsius Temperature Scale

Kelvin Temperature Scale

Density (ratio of mass vs. volume):

for a certain matter, its density is one of the characteristic to distinguish from one another

Atom has equal number of positive charge (from protons) and

negative charge (from electrons)

Charge by position on the Periodic Table

• Group IA = +1 (Li+, Na+, K+, etc),

• Group IIA = +2 (Mg2+, Ca2+, Ba2+, etc),

• Ag+

• Zn2+

• Al3+