The balanced reaction is
CaCO3 + 2 NaF -> CaF2 + Na2CO3
If you start with 20.0 grams CaCO3, how many moles of CaCO3 do you have?
20.0
2.00
.200
.0200
.0386
If you start with .500 moles of NaF, how many moles of CaF2 will form
.500
1.00
1.50
2.00
0.250
What is the sum of the coefficients (including “1”) of the following reaction?
Sodium sulfate + calcium hydroxide ???
4
5
6
7
9
Predict the precipitate that forms: HCl + AgNO 3 ???
HNO3
HCl
AgNO3
AgCl
no precipitate forms
DrWLS answered this for you below, for the first one. We want to see some work for the others. If you can't get started, repost one question at a time, and tell us exactly what you don't understand.
A mixture is easier to separate than a compound because a compound is chemically bounded.
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I answered #2 and #3 at the original post.
To find the number of moles of CaCO3 when starting with 20.0 grams, you need to use the molar mass of CaCO3.
1. Find the molar mass of CaCO3:
Ca: 1 atom x 40.08 g/mol = 40.08 g/mol
C: 1 atom x 12.01 g/mol = 12.01 g/mol
O: 3 atoms x 16.00 g/mol = 48.00 g/mol
Now add the masses together:
40.08 g/mol + 12.01 g/mol + 48.00 g/mol = 100.09 g/mol
2. Use the molar mass to convert grams to moles:
Moles = Mass / Molar mass
Moles = 20.0 g / 100.09 g/mol
Therefore, you have 0.20 moles of CaCO3.
For the question about predicting the precipitate in the reaction HCl + AgNO3, we need to look at the solubility rules.
1. HCl is hydrochloric acid and is soluble in water, so it does not form a precipitate.
2. AgNO3 is silver nitrate. According to the solubility rules, most nitrates are soluble, so AgNO3 is soluble and doesn't form a precipitate.
Therefore, no precipitate forms in this reaction.
To find the sum of the coefficients in the reaction "Sodium sulfate + calcium hydroxide ???," we need to write the balanced equation for the reaction.
The balanced equation is: Na2SO4 + Ca(OH)2 -> 2 NaOH + CaSO4
The coefficients in this equation are:
1 Na2SO4 + 1 Ca(OH)2 -> 2 NaOH + 1 CaSO4
Now we add up the coefficients: 1 + 1 + 2 + 1 = 5
So the sum of the coefficients is 5.
To find the number of moles of CaF2 formed when starting with 0.500 moles of NaF, we need to use the balanced equation and stoichiometry.
In the balanced equation: CaCO3 + 2 NaF -> CaF2 + Na2CO3
The ratio between NaF and CaF2 is 2:1. This means for every 2 moles of NaF, we get 1 mole of CaF2.
Therefore, if we start with 0.500 moles of NaF, we will have 0.250 moles of CaF2 formed.
So the answer is 0.250 moles.
I hope this helps! Let me know if you have any further questions.