Chapter 3 Flashcards
What is one mole equivalent to?
6.022 x 10 ^23 something’s
What does MM stand for?
Mass per mole
What are the units for MM?
G/mol or mol/g
What’s the mole of hydrogen?
1
What’s the mole of carbon?
12.01
What is molar mass equivalent to?
The molecular weight, formula weight, and molecular mass
what is the molar mass of SO2
64.07g/mol
what is the molar mass of Mg(NO3)2 * 3H2O
202.3 g/mol
silver (ag) is used in jewelry and tableware but no longer in U.S. coins. How many grams of Ag are in 0.0342 moles of Ag?
3.69g Ag
gallium (Ga) is a key element in solar panels, calculators and other light sensitive electronic devices. How many Ga atoms are in 2.85 x 10^-3 mol of gallium?
1.72 x 10^2 atoms of Ga
nitrogen dioxide is a component of urban smog that forms from the gases in car exhausts. How many molecules are in 8.92 g of nitrogen dioxide?
1.7 x 10^23 molecules of NO2
determine the mass percent of each element in C6H12O6
39.99% - C , 6.73% - H , 53.28% - O
formula to find mass of element within a compound
mass of element in a compound = mass fraction of element x mass of compound
whats the mass of carbon in 16.55g of glucose?
6.618g C
what’s the empirical formula for hydrogen peroxide
HO
what’s the molecular formula for hydrogen peroxide
H2O2
a sample of an unknown compound contains 0.21 mol of zinc, 0.14 mole of phosphorus, and 0.56 mol of oxygen. what is its empirical formula?
Zn3P2O8
analysis of a sample of an ionic compound yields 2.82 g of Na, 4.35 g of Cl, and 7.83 g of O. what is the empirical formula and the name of the compound?
NaClO4
what does the molecular formula give you
the actual number of moles of each element present in 1 mol of a compound
what goes empirical formula mass require you to solve
the molecular formula
a compound containing chlorine and silicon atoms contains 79.1 mass percent Cl. what is the empirical formula of the compound? if the molar mass is 269g/mol, what is the molecular formula?
empirical formula is SCl3
molecular formula is Si2Cl6
which side of the equation are reactants written
on the left
Within the cylinders of a car’s engine, the hydrocarbon
octane (C8H18), one of many components of gasoline, mixes
with oxygen from the air and burns to form carbon dioxide
and water vapor. Write a balanced equation for this
reaction.
2C8H18(l) +25O2(g) –>16O2(g) +9H2O(g)
Copper(I) sulfide is reacted in the presence of oxygen gas
to form powdered copper(I) oxide and gaseous sulfur
dioxide. How many moles of oxygen are required to react 10.0 mol
of copper(I) sulfide?
15.0 mol O2
During the process of reacting copper(I) sulfide, how
many grams of sulfur dioxide form when 10.0 mol of
copper(I) sulfide reacts?
640.7 grams SO2
Elemental sulfur occurs as octatomic molecules, S8. What
mass (g) of fluorine gas is needed to react completely
with 17.8 g of sulfur to form sulfur hexafluoride?
63.3 g F2
Calculate the maximum numbers of grams of H2S that
can form when 158 g of aluminum sulfide reacts with
131 g of water. And how much of the excess reactant
remains?
a) 108H2S will form
b) 17H20 left over
what is theoretical yield
amount of product calculated using the mole ratios from the balanced equation
what is actual yield
the amount of product actually obtained. the actual yield is usually less than the theoretical yield
what’s the formula for percent yield
actual yield/theoretical yield x 100
what might explain a yield > 100%?
if there is another substance that somehow added to the chemical reaction
Silicon carbide (SiC) is made by reacting sand(silicon
dioxide, SiO2) with powdered carbon at high temperature.
Carbon monoxide is also formed. What is the percent yield
if 51.4 g of SiC is recovered from processing 100.0 g of
sand?
77.1 % yield
