67,874 views
35 votes
35 votes
How many moles is
55 g of Naci?
0.025 g of NaCO3?

User Anshad Ali KM
by
3.1k points

2 Answers

13 votes
13 votes

Final answer:

To find the number of moles of NaCl and NaCO3, divide the given masses by their respective molar masses.

Step-by-step explanation:

To determine the number of moles of a substance, we use the equation:

Moles = mass / molar mass

For 55 g of NaCl, we need to find the molar mass of NaCl. The molar mass of Na is 22.990 g/mol and the molar mass of Cl is 35.453 g/mol. So, the molar mass of NaCl is 22.990 + 35.453 = 58.443 g/mol. Therefore, the number of moles of NaCl is 55 g / 58.443 g/mol = 0.942 moles.

For 0.025 g of NaCO3, we need to find the molar mass of NaCO3. The molar mass of Na is 22.990 g/mol, the molar mass of C is 12.011 g/mol, and the molar mass of O is 15.999 g/mol. So, the molar mass of NaCO3 is 22.990 + 12.011 + (3 × 15.999) = 105.988 g/mol. Therefore, the number of moles of NaCO3 is 0.025 g / 105.988 g/mol = 0.000236 moles.

User Flauntster
by
2.7k points
20 votes
20 votes

Answer:

0.940mol &

0.000301mol respectively.

Step-by-step explanation:

number of moles = given mass / molar mass

given mass of Nacl = 55g Molar mass = 23 + 35.5

n=m/M = 55g/58.5g/mol = 0.940mol

note- (add the atomic weights of sodium and chlorine to get the molar mass of Nacl.) = 58.5g/mol

similarly, NaCO3 = 23 + 12 + 16*3 = 83g/mol

n=m/M = 0.025g/83g/mol = 3.01 * 10^-4 = 0.000301mol

extra: If you ever get asked to put it in number of particles just use the relation of 1mole = 6.02 * 10^23 particles.

User Dmitry Grigoryev
by
2.8k points