Answer:
126.5g
Explanation:
n=<u>m</u><u> </u>
M
where n is moles
m is mass of substance
M is molar mass
molar mass of sodium is 23g/mol
m=nM
m=5.5(23)
m=126.5
Answer:
0.11mol/dm³
Explanation:
The reaction expression is given as:
HCl + NaOH → NaCl + H₂O
Volume of acid = 25cm³ = 0.025dm³
Volume of base = 18.4cm³ = 0.0184dm³
Concentration of base = 0.15mol/dm³
Solution:
The concentration of hydrochloric acid = ?
To solve this problem, let us first find the number of moles of the base;
Number of moles = concentration x volume
Number of moles = 0.15mol/dm³ x 0.0184dm³ = 0.00276mol
From the balanced reaction equation;
1 mole of NaOH will combine with 1 mole of HCl
Therefore, 0.00276mol of the base will combine with 0.00276mol of HCl
So;
Concentration of acid = = = 0.11mol/dm³
Answer : The molar mass of an acid is 266.985 g/mole
Explanation : Given,
Mass of an acid (HX) = 4.7 g
Volume of NaOH = 32.6 ml = 0.0326 L
Molarity of NaOH = 0.54 M = 0.54 mole/L
First we have to calculate the moles of NaOH.
Now we have to calculate the moles of an acid.
In the titration, the moles of an acid will be equal to the moles of NaOH.
Moles of an acid = Moles of NaOH = 0.017604 mole
Now we have to calculate the molar mass of and acid.
Now put all the given values in this formula, we get:
Therefore, the molar mass of an acid is 266.985 g/mole
The empirical formula for pyrite is FeS2.
HOW TO CALCULATE EMPIRICAL FORMULA:
- The empirical formula represents the simplest whole number ratio of constituents element of a compound. The empirical formula of pyrite can be calculated as follows:
46.5 mass % Fe = 46.5g of Fe
53.5 mass % S = 53.5g of S
- Next, we divide each element's mass value by its molar mass
Fe = 46.5g ÷ 56g/mol = 0.83mol
S = 53.5g ÷ 32g/mol = 1.67mol
- Next, we divide each mole value by the smallest (0.83mol)
Fe = 0.83mol ÷ 0.83 = 1
S = 1.67mol ÷ 0.83 = 2.014
Approximately, the ratio of Fe to S is 1:2. Therefore, the empirical formula of pyrite is FeS2.
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