Ch. 1
How many hydrogen atoms are in CH4O2?
4
What is the difference in a cation and anion?
cation: positive charge
anion: negative charge
What is the difference in ionic vs. molecular compounds?
molecular: only nonmetals
ionic: metal and nonmetals
How many moles of hydrogen are in CH3(OCH3)3?
12
density = mass/volume
Isotopes have different numbers of ____________.
neutrons
What is the name of Br2O?
(is it molecular or ionic?)
dibromine monoxide
What does the number 6.022 x 1023 mean?
Avagadro's number
It's how many atoms/molecules/ions are in 1 mole of a substance
A chemist puts equal amounts of hydrogen atoms and fluorine atoms in a container. When they come back later, the atoms have combined to make HF molecules. Is this a chemical or physical change?
Chemical change
Physical changes change the state of matter (solid vs. liquid vs. gad)
Chemical changes change the chemical formula
Name the 3 parts of an atom and what charge (if any) they have.
protons: positive charge
neutrons: neutral/no charge
electrons: negative charge
What compound is iodine and calcium most likely to make?
(figure out which ions calcium and iodine will likely make first)
CaI2
How many atoms are in 4 moles of HF?
2.4 x 1024 atoms
How many sig figs are in 0.1230?
4
How many protons and neutrons are in an isotope of 102Rh?
protons: 45
neutrons: 57
What is the name of CO32-?
carbonate
A chemist weighs 33.7 grams of tin. How many moles is this?
0.284 mol
What is the scientific notation for 0.00004261?
4.261 x 10-5
How many electrons does a neutral atom of Si have?
How many electrons does Si+ have? Si-?
neutral Si: 14
Si+: 13
Si-: 15
If ClO3- is "chlorate", what is the name for ClO2-?
(You've lost 1 oxygen)
chlorite
How many moles are in 9.3 grams of BeS?
0.23 mol
molar mass = 41.07 g/mol
9.3 g/41.07 = 0.23 mol