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
What is Avogadro's number? What does it mean?
6.022 x 1023
It's how many atoms/molecules/ions are in 1 mole of a substance
How many nitrogen atoms are on the right side of this equation?
N2 + 3H2 → 2NH3
2
density = mass/volume
Isotopes have different numbers of ___________.
neutrons
What is the name of Br2O?
(is it molecular or ionic?)
dibromine monoxide
molecular
How many moles of hydrogen are in CH3(OCH3)3?
12
Balance the chemical equation:
N2(g) + H2(g) → NH3(g)
N2(g) + 3 H2(g) → 2 NH3(g)
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 they will make first)
bonus points if you can name the new compound!
CaI2
How many molecules of HF are in 4 moles of HF?
2.4 x 1024 atoms
What is the total number of oxygen atoms on the left-hand side of this chemical equation?
2 Ca2(PO4)2(s) + 4 SiO2(s) + 12C(s) → 4 CaSiO3(s) + 12CO(g)
24 oxygen 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
Balance the chemical equation:
Fe2O3(s) → Fe(s) + O2(g)
2 Fe2O3(s) → 4 Fe(s) + 3 O2(g)
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
What is the formula for lead(IV) permanganate?
Pb(MnO4)4
Calculate the number of oxygen atoms in a 130.0 g sample of dinitrogen tetroxide (N2O4).
3.403 x 1024 oxygen atoms
Write a balanced equation for:
Aqueous hydrochloric acid (HCl) reacts with solid iron(II) sulfide to form hydrogen sulfide gas (H2S) and aqueous iron(II) chloride.
2 HCl(aq) + FeS(s) → H2S(g) + FeCl2(aq)