Answer:
2.05*10⁻⁵ moles of CF₂ can dissolve in 100 g of water.
12.82 moles of CaF₂ will dissolve in exactly 1.00 L of solution
Explanation:
First, by definition of solubility, in 100 g of water there are 0.0016 g of CaF₂. So, to know how many moles are 0.0016 g, you must know the molar mass of the compound. For that you know:
- Ca: 40 g/mole
- F: 19 g/mole
So the molar mass of CaF₂ is:
CaF₂= 40 g/mole + 2*19 g/mole= 78 g/mole
Now you can apply the following rule of three: if there are 78 grams of CaF₂ in 1 mole, in 0.0016 grams of the compound how many moles are there?

moles=2.05*10⁻⁵
<u><em>2.05*10⁻⁵ moles of CF₂ can dissolve in 100 g of water.</em></u>
Now, to answer the following question, you can apply the following rule of three: if by definition of density in 1 mL there is 1 g of CaF₂, in 1000 mL (where 1L = 1000mL) how much mass of the compound is there?

mass of CaF₂= 1000 g
Now you can apply the following rule of three: if there are 78 grams of CaF₂ in 1 mole, in 1000 grams of the compound how many moles are there?

moles=12.82
<u><em>12.82 moles of CaF₂ will dissolve in exactly 1.00 L of solution</em></u>
<h2>
Answer :</h2><h3><u>
QUESTION ①)</u></h3>
✔ C5H4 has a molecular molar mass of :
<em>M(C5H4) = 5 x M(C) + 4 x M(H) </em>
- M(C5H4) = 5 x 12 + 4 x 1
- M(C5H4) = 60 + 4
- M(C5H4) = 64 g/mol
✔ The molecular mass of C5H4 is therefore 64 g/mol.
<h3>This is double the molar mass of C5H4, this molecule has the formula 2C5H4.</h3>
Calcula el Tanta por ciento en peso de soluto
Answer:
3.46 x 10²⁴ molecules.
Explanation:
- <em>Knowing that every one mole of a substance contains Avogadro's no. of molecules (NA = 6.022 x 10²³).</em>
<em><u>Using cross multiplication:</u></em>
1.0 mole of HBr → 6.022 x 10²³ molecules.
5.75 mole of HBr → ??? molecules.
∴ The no. of molecules of HBr are in 5.75 mol = (6.022 x 10²³ molecules) ( 5.75 mole) / (1.0 mol) = 3.46 x 10²⁴ molecules.