practice homework chapters one through three
Which of these samples has the smallest mass?
0.00016 mg
15) What is the percent by mass of salt in a mixture that contains 150 g of salt, 1.2 kg of flour and 650 g of sugar?
0.075%
What is the total dose required for a 140 lb patient if the amount required is 28 mg/kg bodyweight?
1.8 g
27) The half life of a specific radionuclide is 8 days. How much of an 80 mg sample will be left after 24 days?
10 mg
Mercury-202 has how many neutrons in its nucleus?
122
How many valence electrons would be found in the correct Lewis dot structure of C2H6?
14
What is the mass of 3.61 moles of Ca?
145 g
Calculate the mass of carbon in 30.0 g CH3CH2CH2CH3.
24.8 g
The total number of valence electrons in a molecule of SOF2
26
How many neutrons are in a neutral atom of Fe-56?
30
20) What is the coefficient for 02 when this equation is balanced with the lowest whole number coefficients? C2H6 + 02 - CO2 + H20
7
The element rhenium (Re) exists as two stable isotopes and 18 unstable isotopes. Rhenium-185 (185RE) has in its nucleus:
75 protons, 110 neutrons
What is the correct symbol for the element copper?
Cu
What is the correct symbol for the isotope of copper with a mass number of 63?
Cu 63 over 29
Iron pyrite (fool's gold) is iron (II) sulfide. What is its formula?
FeS
The reaction of calcium and sulfur produces
CaS
Which particle(s) are in the nucleus?
Protons and neutrons
Which of the following is a chemical reaction?
Rusting of iron
What is the correct name for a molecule of SO3?
Sulfur trioxide
Determine the molecular geometry of the following molecule and decide if it is polar or nonpolar. PF3
trigonal pyramidal, polar
Which of the following substances has the lowest density?
mass of 5 mg and a volume of 25 uL
All the different kinds of substances that make up all of the material of the universe are known collectively as:
matter
A thimble of water contains 4.0 x 1021 molecules. The number of moles of H20 is:
6.6 x 10-3
Which of the following is an example of a heterogeneous mixture?
Blood
Identify the correct ordering of attractions among particles in the three states of matter.
Solid > liquid > gas
