Chem 133 Exam 2 Questions and Answers latest
Update | 100% Correct
What is the mass in grams of 9.76 × 10^12 atoms of naturally occurring sodium? -
✅✅First we get the moles : 9.76 x 10^.02 x 10^23 =1.62 x 10^-11
second we multiply by the atomic mass :
1.62 x 10^-11 mol x 22.9898 g/mol=3.73 x 10^-10 g
How many oxygen atoms are contained in 2.74 g of Al2(SO4)3? - ✅✅2.74
grams Al2(SO4)3 x 1 mol Al2(SO4).17 grams Al2(SO4)3 x
12 mol O / 1 mol Al2(SO4)3 x 6.022x10^23 Oxygen atoms / 1mole O
= 5.79 x 10^22 Oxygen atoms
Which one of the following is a diprotic acid? - ✅✅Diprotic' is a fancy term that
means 'two protons.' If you're looking for a diprotic acid, you're looking for one
that can give off two protons when it dissociates. Another way to say 'proton,' is
'hydrogen ion,' so you're looking for the acid that has two hydrogens in front of it.
That's your diprotic acid.
The balanced net ionic equation for precipitation of CaCO3 when aqueous
solutions of Na2CO3 and CaCl2 are mixed is ________. - ✅✅Ca2+(aq) + CO3 2-
(aq) → CaCO3 (s)
The net ionic equation for the reaction between aqueous sulfuric acid and
aqueous sodium hydroxide is ________. - ✅✅e ionic equation for any acid
reacting with any base is: H+(aq) + OH-(aq) --> H2O(l)
, The H2SO4 provides the H+ ions. The OH- ions come from the sodium hydroxide.
The sodium ions and the sulphate ions remain unchanged in solution so they are
called spectator ions and are not used in the ionic equation
What is the mass % of aluminum in aluminum sulfate (Al2(SO4)3) rounded to
three significant figures? - ✅✅To find the percent composition of Al₂(SO₄)₃, you
divide the total mass of each atom by the molecular mass and multiply by 100 %.
Explanation:
% by mass =
mass of component/
total mass
× 100 %
Mass of 2 Al atoms = 2 Al atoms ×
26.98
/
1
Al atom
= 53.96 u.
Mass of 3 S atoms = 3 S atoms ×
32.06
/
1
Update | 100% Correct
What is the mass in grams of 9.76 × 10^12 atoms of naturally occurring sodium? -
✅✅First we get the moles : 9.76 x 10^.02 x 10^23 =1.62 x 10^-11
second we multiply by the atomic mass :
1.62 x 10^-11 mol x 22.9898 g/mol=3.73 x 10^-10 g
How many oxygen atoms are contained in 2.74 g of Al2(SO4)3? - ✅✅2.74
grams Al2(SO4)3 x 1 mol Al2(SO4).17 grams Al2(SO4)3 x
12 mol O / 1 mol Al2(SO4)3 x 6.022x10^23 Oxygen atoms / 1mole O
= 5.79 x 10^22 Oxygen atoms
Which one of the following is a diprotic acid? - ✅✅Diprotic' is a fancy term that
means 'two protons.' If you're looking for a diprotic acid, you're looking for one
that can give off two protons when it dissociates. Another way to say 'proton,' is
'hydrogen ion,' so you're looking for the acid that has two hydrogens in front of it.
That's your diprotic acid.
The balanced net ionic equation for precipitation of CaCO3 when aqueous
solutions of Na2CO3 and CaCl2 are mixed is ________. - ✅✅Ca2+(aq) + CO3 2-
(aq) → CaCO3 (s)
The net ionic equation for the reaction between aqueous sulfuric acid and
aqueous sodium hydroxide is ________. - ✅✅e ionic equation for any acid
reacting with any base is: H+(aq) + OH-(aq) --> H2O(l)
, The H2SO4 provides the H+ ions. The OH- ions come from the sodium hydroxide.
The sodium ions and the sulphate ions remain unchanged in solution so they are
called spectator ions and are not used in the ionic equation
What is the mass % of aluminum in aluminum sulfate (Al2(SO4)3) rounded to
three significant figures? - ✅✅To find the percent composition of Al₂(SO₄)₃, you
divide the total mass of each atom by the molecular mass and multiply by 100 %.
Explanation:
% by mass =
mass of component/
total mass
× 100 %
Mass of 2 Al atoms = 2 Al atoms ×
26.98
/
1
Al atom
= 53.96 u.
Mass of 3 S atoms = 3 S atoms ×
32.06
/
1
