Advertisements
Advertisements
प्रश्न
Solve problem:
Calculate the number of moles of magnesium oxide, MgO in
- 80 g, and
- 10 g of the compound.
(Average atomic masses of Mg = 24 and O = 16)
Advertisements
उत्तर
Given: i. Mass of MgO = 80 g
ii. Mass of MgO = 10 g
To find: Number of moles of MgO
Formulae: Number of moles (n) = `"Mass of a substance"/"Molar mass of a substance"`
Calculation: i. Molecular mass of MgO = (1 × Average atomic mass of Mg) + (1 × Average atomic mass of O)
= (1 × 24 u) + (1 × 16 u)
= 40 u
∴ Molar mass of MgO = 40 g mol−1
Mass of MgO = 80 g
Number of moles (n) = `"Mass of a substance"/"Molar mass of a substance"`
= `(80 "g")/(40 "g mol"^-1)`
= 2 mol
ii. Mass of MgO = 10 g, Molar mass of MgO = 40 g mol–1
Number of moles (n) = `"Mass of a substance"/"Molar mass of a substance"`
= `(10 "g")/(40 "g mol"^-1)`
= 0.25 mol
- The number of moles in 80 g of magnesium oxide, MgO = 2 mol
- The number of moles in 10 g of magnesium oxide, MgO = 0.25 mol
APPEARS IN
संबंधित प्रश्न
Which of the following has the largest number of atoms?
What is the ratio of molecules in 1 mole of NH3 and 1 mole of HNO3?
Solve problem:
Calculate the number of an atom of the following (Given: Atomic mass of I = 127 u).
254 u of iodine (I)
Solve problem:
Calculate the number of an atom of the following (Given: Atomic mass of I = 127 u).
254 g of iodine (I)
24 g of carbon reacts with some oxygen to make 88 grams of carbon dioxide. Find out how much oxygen must have been used.
Solve problem:
Calculate the number of atoms of the following. (Average atomic mass : N = 14 u, S = 32 u)
0.4 mole of nitrogen
Solve problem:
Calculate the number of atoms of the following. (Average atomic mass : N = 14 u, S = 32 u)
1.6 g of sulfur
Calculate the number of atoms of hydrogen present in 5.6 g of urea, \[\ce{(NH2)2CO}\]. Also calculate the number of atoms of N, C, and O.
Solve problem:
Calculate the mass of sulfur dioxide produced by burning 16 g of sulfur in excess of oxygen in the contact process. (Average atomic mass : S = 32 u, O = 16 u)
Explain the need of the term average atomic mass.
Which one of the following represents 180 g of water?
Two 22.4 litre containers A and B contains 8 g of O2 and 8 g of SO2 respectively at 273 K and 1 atm pressure, then
What is the mass of precipitate formed when 50 ml of 8.5% solution of AgNO3 is mixed with 100 ml of 1.865% potassium chloride solution?
Which of the following is/are true with respect to carbon-12.
Define relative atomic mass.
Calculate the average atomic mass of naturally occurring magnesium using the following data.
| Isotope | Isotopic atomic mass | Abundance (%) |
| Mg24 | 23.99 | 78.99 |
| Mg25 | 24.99 | 10.00 |
| Mg26 | 25.98 | 11.01 |
An element has a bee structure with cell edge of 288 pm. The density of element is 7.2 g cm-3. What is the atomic mass of an element?
How many moles of ammonia are present in 5.6 cm3 of ammonia gas at STP?
What is the average mass of an element if it has two isotopes, one of mass 6.015 u with 8.24 % and other of mass 7.016 u with 91.26% respectively?
The unit of atomic mass, amu is replaced by u, here u stands for ______.
A 100 g of sample of haemoglobin on analysis was found to contain 0.34% Fe by mass. If each haemoglobin molecule has four Fe2+ ions, the molecular mass of haemoglobin is: (Fe = 56 amu)
It is found that in 11.2 L at 0°C and 1 atm, of any gaseous compound of 'X', there is never less than 15.5 gm of 'X'. It is also found that 11.2 L of vapours of 'X' at 0°C and 1 atm, weighs 62 gm. The atomicity of 'X' is ______.
Which symbol replaces the unit of atomic mass, amu?
0.05 F electricity is passed through CuSO4 solution. Calculate the mass of Cu produced at cathode? (molar mass of Cu = 63.5 g mol-1)
