Definitions
Identify each of the following as an element, compound, homogeneous mixture, or heterogeneous mixture:
Air
Water
Granite Rock
Oxygen
Element - Oxygen
Compound- Water
Homogeneous Mixture - Air
Heterogeneous Mixture - Granite Rock
Calculate the following:
(4.0 x 10-4) x (2.0 x 106)
8.0 x 102
Does filtration rely on physical or chemical properties?
Physical
What one observation is needed to be certain that a chemical reaction occurred?
Change in composition
What happens to the density of a substance when that substance gets colder?
Density Increases
How many Carbon, Hydrogen and Oxygen atoms are in one molecule of C6H12O6?
Carbon - 6
Hydrogen - 12
Oxygen - 6
Calculate the following:
(4.51 x 107) + (2.1 x 106)
47.2 x 106
4.7 x 107
Does distillation rely on physical or chemical properties?
Physical
Is burning wood a chemical or physical reaction? Why?
Chemical, it changes the chemical composition of the wood.
If 103 mm = 1 m, how many mm3 are in 1 m3?
109 mm3
What distinguishes a mixture and a substance?
Mixtures can be physically separated. Substances can be separated by a chemical change into elements.
Write 0.000408 in scientific notation.
4.08 x 10-4
Devise a way to separate sand from a mixture of charcoal, sand, sugar, and water.
Add water to dissolve the sugar
Separate the sugar water from the sand and charcoal using filtration
Hand separate the charcoal from the sand using your hands and different colors
A reactant is what you have at the start of the reaction, the product is what you have at the end of the reaction.
Convert 22 kg/hr into grams per minute. Give your answer in scientific notation.
3.7 x 102 g/min
Classify the following as a physical or chemical reaction:
Copper wire is bent
Charcoal burns in a grill
Bread dough rises when yeast is added
Sugar dissolves in water
Copper wire is bent - physical
Charcoal burns in grill - chemical (color change)
Bread dough rises when yeast is added - chemical (production of a gas)
Sugar dissolves in water - physical
How many significant figures are in the following measurement:
6500 g
2
What are the rules for scientific notation's exponent and coefficient?
Always a number 1 ≧ coefficient < 10
Exponent:
An integer (whole number)
+ = the amount of times that the Coefficient must be multiplied by 10
Look at the table on the board,
Which of the following substances is solid at 1080 degrees C?
water, Sulfur, Gold and Copper?
Copper
What is the mass of a cube of Al that is 3.0 cm on each edge? The density of Al is 2.7g/cm3.
73g
50 grams of compound AB2 decomposes into elements A and B. If this reaction produces 20 g of A, what mass of B is produced?
30 g
Law of Conservation of Mass
How many significant figures are in the following measurement:
0.0400 m
3
What are the rules for sig figs?
How do you know what to report a number to?
All nonzero digits are significant.
Zeroes between two significant figures are themselves significant.
Zeroes at the beginning of a number are never significant.
Zeroes at the end of a number are significant if a decimal point is written in the number.
Whatever is the lowest significant number in the problem, is the number you have to report to.
If I give you a known density of a product and how much I have of it in grams, can you determine the volume? How?
Density = mass / Volume
Input the number I gave you for the density as well as the mass in the equation. Solve using algebra.
What two unit types does density have to have?
Hint: think about the formula.
mass (grams, kg, etc), volume (L or cubic m or cm, etc)