Significant Figures and Calculations
70,000.90 min
is how many significant figures?
7
How many meters are in 1 km?
1000 m
Element, Compound, or Mixture:
CuCl2
Compound
If a substance is in a liquid state, what will you see in parenthesis next to the substance?
(l)
Chemical or physical Change:
4 Fe(s) + 3 O2(g) → 2 Fe2O3(s)
Chemical - new substance is made
Name one of Ms. Gladden's dogs:
Blaze, Paisley, Copper
Name the three rules for 0's when determining significant figures
(sandwiched, leading, trailing)
1. All sandwiched zeroes are significant
2. Leading 0's are never significant
3. Trailing 0's are only significant if there is a decimal in the number
how many centimeters are in 1 m?
100 cm
Which of the following is NOT a mixture
1. air
2. tea
3. sand
4. Pure Water (H2O)
Pure water
The state of matter that will completely fill the available space is:
gas
Crushing, grinding, dissolving are examples of:
physical changes
Report to the correct significant figure:
3.431 - 2.6
0.8 (decimal place!)
0025.0 is how many significant figures?
3
An object measured to be 13cm. What is the length in km? (Use dimensional analysis and report your answer in sci notation)
13 cm x 1 m/100 cm x 1 km/1000 m = 1.3 x 10-4 km
A substance that is made up of two or more substances but is NOT chemically combined is a __________________.
mixture
Which of the following samples at standard tempurature and pressure will expand to fill a 932 cm2 closed container?
1. 8 grams of H2O (s)
2. 8 grams of C6H12O6 (l)
3. 12 grams of MgCl2 (g)
4. 12 grams of MgO (s)
12 grams of MgCl2 (g)
Flammability and Reactivity are examples of:
Chemical Properties
The amount of SPACE a gas takes up is its:
volume
A metal cylinder with a mass of 7.12g has a volume of 18 cm3. What is the density of the cylinder? (reported to the correct # of significant figures)
7.12/18 = 0.40 g/cm3 (two significant figures)
The mass of a sample of CaCl2 was measured to be 14.5 g. What is the mass in milligrams? (use dimensional analysis and report the final answer in scientific notation)
14.5 g x 1000 mg/1 g = 1.45 x 104 mg
Which of the following is a Heterogenous mixture
1. iced tea
2. mixed nuts
3. coffee
d. jello
mixed nuts
List 2 properties of a liquid substance
1. indefinite shape
2. definite volume
3. able to flow
4. particles flow close to one another & are still attracted to one another
True or False
Water is colorless is an example of an extensive physical property.
False - its intensive no matter how much water you have, it will always be colorless!
solid
The initial volume of water was measured with a graduated cylinder at 20.00 mL. An unknown cylinder was placed in graduated cylinder and the final volume was 24.00 mL. The mass was measured to 29.24 g. What is the density (to the correct sig fig)?
7.31 g/mL or g/cm3
Convert the following into scientific notation: 38000000000000000 m
3.8 x 1016 m
Which of the following represents COMPOUNDS only:
1. CO2, H2O, NH3
2. H2, N2, O2
3. H2, Ne, NaCl
4. MgO, NaCl, O2
1. CO2, H2O, NH3
The phase change that occurs when a solid turns directly into a gas is:
sublimation
True or False:
The metal has a mass of 75 g is an intensive property.
False, extensive because the more that is added, the more mass it will have
True or false:
Air is a heterogeneous mixture
False homogenous