Chapter 1
Definition of an atom
the smallest unit of an element that retains the properties of the matter
Some early philosophers believed that matter was composed of small, indestructible particles called“atomos”
Leucippus and Democritus
Compounds are made of atoms held together by
covalent bonds
1 mole of H2O contains 2 moles of H and 1 mole of O:
Molar mass = formula mass (in g/mole)
molar mass of 1 mole H2O =
18.015 𝑔
What is an element's atomic number?
An element's atomic number is the number of protons in the nucleus of an atom of that element.
Dissolving sugar in hot coffee is what type of change?
Chemical Change
Because there was no experimental way of proving who wascorrect, the most important person was assumed to be correct
Aristotle
Describe Ionic Bonds (metals and electrons)
metal and non-metal
transfer of electrons
Find the mass of table salt (NaCl) that contains 2.4 g of Na (39%)
6.2 g NaCl
What are the characteristics of metals, nonmetals, and metalloids?
Metals are typically shiny, malleable, and good conductors of electricity and heat. Nonmetals are varied in appearance and poor conductors of heat and electricity. Metalloids have properties that are intermediate between metals and nonmetals.
What is the international system of units (SI)for temperature, mass, time, and length?
Kelvin, kilogram, second, meter
How do you find the mass of an element?
The total number of protons (#p) and neutrons (#n) is given by the mass number (A)
Write the formula for the ionic compound that forms
between aluminum (Al) and oxygen (O)
Al2O3
A silver ring contains 1.1 x 10^(22) silver atoms. How many moles of silver are in the ring?
1.8 x 10^(-2) moles Ag
What are the main characteristics of alkaline earth metals?
Alkaline earth metals (Group 2) are reactive metals with two valence electrons, are harder than alkali metals, and react with water to form alkaline solutions.
Convert 3.5 mg to grams.
3.5 x 10 ^ (-3)
The atoms who lose electrons are called
cations
Give the name of the three compounds:
ClO-
BaCl2 6H2O
H2SO4(aq)
hypochlorite
barium chloride hexahydrate
sulfuric acid
Calculate the moles of carbon in 0.0265 g of pencil lead.
2.21 x 10^(-3) moles C
What are noble gases, and what is unique about their chemical behavior?
Noble gases (Group 18) are inert, colorless, and odorless gases with a full valence shell of electrons, making them extremely unreactive.
Human fat has a density of 0.918 g/cm3. How much volume (in cm3)is gained by a person who gains 10.0 lb of pure fat?
4.95 x 10 ^ (3) cm^(3)
Calculate the number of atoms in 2.45 mol of copper
1.48 x 10^(24) atoms Cu
What is the mass in grams of 4.78 x 10^(24) molecules of NO2?
365. g NO2
Determine the empirical formula of a compound that is 36.4% Mn, 21.2% S, and 42.4% O by mass.
MnSO4
Predict the chemical properties of an element with atomic number 17.
The element with atomic number 17 is chlorine, a halogen. It is highly reactive, has seven valence electrons, and tends to form salts when combined with metals.