Significant Figures
how many sig figs are in the number 0.56?
2
What determines the identity of an element?
Its atomic number / protons
How many milliliters are in a 12 oz soda can?
1 oz = 0.0296 L
1 L = 1,000 mL
355mL
Which of the following are intensive properties? Extensive properties?
a. boiling point
b. color
c. volume
d. weight
a & b are intensive
c & d are extensive
What is the answer to this equation? 14.023/0.0032
4,400
How many protons, neutrons, and electrons are in this element?
A= 25
Z = 12
A is the mass number (Protons + neutrons)
Z is the atomic number (# of protons)
To find protons and electrons, just look at the atomic number (Z). To find neutrons, just subtract Z from A (25-12).
Protons: 12
Neutrons: 13
Electrons:12
The distance from Santa Maria to Los Alamos is 16.25 miles. What distance is this in cm?
1 mi = 5280 ft
1 in = 2.54 cm
1 ft = 12 in
2.615 x 106 cm
(16.25 miles is the only exact number!)
Which of the following are chemical properties? Physical properties?
a. texture
b. flammability
c. acidity
d. freezing point
a & d are physical properties (descriptors of a substance and can be tested and not change the chemical composition of the cmpd)
b & c are chemical properties (can only be found through a reaction and change the chemical composition of the cmpd).
What is the answer to this equation? 2984.3 - 10.019
2974.3
What are the common charges of these elements?
1. Sulfur
2. Barium
3. Sodium
4. Phosphorus
1. 2-
2. 2+
3. 1+
4. 3-
#6 Saffron costs $368.00 per ounce. Determine how many grams you can purchase for $15.00
1 oz = $368.00, 16 oz = 1 lb, 1 kg = 2.2 lb
1.158 g
No matter where it is found, glucose consists of carbon, oxygen, and hydrogen combined in a 6:1:8 ratio by mass. This observation is a statement of the
a) Law of Conservation of Mass
b) Law of Multiple Proportions
c) Law of Definite Composition
d) Law of Conservation of Energy
e) None of the above
c) Law of Definite Composition
What is the answer to this equation? 12.894 + 2093.3 x 0.9874
2080
(when we multiply 2093.3 and 0.9874 we indicate that that number should have four sig figs, which means that it has no numbers after the decimal place. So, when we add that number to 12.894, we will end with a number that has no numbers after the decimal place!)
What families are the following elements in?
1. Beryllium
2. Iodine
3. Argon
4. Cesium
1. Alkaline earth metals
2. Halogens
3. Noble Gases
4. Alkali metals
Use the conversions below, metric conversions, and dimensional analysis to determine how many milligrams (mg) would be in a sample of 1.442 scruples.
1 apothecary pound = 12 oz
1 oz = 8 drams
3 scruples = 1 dram
1.2153 apothecary pound = 1 English pound
1 kg = 2.20462 English pounds
1,869,000 mg
or 1.839 x 106 mg
What is the percent by mass of oxygen in Triethanolamine (C6H15NO3)?
Triethanolamine molar mass: 149.188 g/mol
47.997/149.188 = 0.32172
32.172%
What is the answer to this equation? 2000.2/(308.2 + 23.32)
6.033
(when we aadd 308.2 and 23.32 we will get a number that has only one number after the decimal point. This number has 4 sig figs. When we then divide 2000.2 by that number with 4 sig figs, we will get a number that has 4 sig figs since it is the least amount of sig figs (2000.2 has 5 sig figs)).
What is the molar mass of sucrose? (C12H22O11)
342.297 g/mol
Naturally occurring copper consists of 69.17% 63Cu, which has an isotope mass of 62.9396 u, and 30.83% 65Cu, which has an isotope mass of 64.9278 u.
What is the atomic mass of copper?
63.55 u
(multiply each percentage by its mass and then add the two together)
Calculate the mass of nitrogen in a 4.75 g sample of nitrogen monoxide, NO, which has a percent composition of 46.68% N and 53.32% oxygen by mass.(pay attention to sig figs!)
2.22 g