Advertisements
Advertisements
प्रश्न
Calculate the number of atoms in 39.4 g gold. Molar mass of gold is 197g mole–1.
Advertisements
उत्तर
We know that,
Molar mass = Mass of Avogadro's number of atoms (Molecules).
= 6.023 × 1023 atoms.
Given, molar mass of gold = 197 g/mol
Now,
∴ 197 g of gold contains = 6.023 × 1023 atoms
∴ 1 g of gold contain = `(6.023 xx 10^23)/197` atoms
∴ 39.4 g of gold contains = `(6.023 xx 10^23 xx 39.4)/197`
⇒ 1.20 × 1023 atoms.
APPEARS IN
संबंधित प्रश्न
Molar volume is the volume occupied by 1 mol of any (ideal) gas at standard temperature and pressure (STP: 1 atmospheric pressure, 0 °C). Show that it is 22.4 litres
An oxygen cylinder of volume 30 litres has an initial gauge pressure of 15 atm and a temperature of 27 °C. After some oxygen is withdrawn from the cylinder, the gauge pressure drops to 11 atm and its temperature drops to 17 °C. Estimate the mass of oxygen taken out of the cylinder (R = 8.31 J mol–1 K–1, molecular mass of O2 = 32 u)
Estimate the average thermal energy of a helium atom at the temperature of 10 million Kelvin (the typical core temperature in the case of a star).
Three vessels of equal capacity have gases at the same temperature and pressure. The first vessel contains neon (monatomic), the second contains chlorine (diatomic), and the third contains uranium hexafluoride (polyatomic).
Is the root mean square speed of molecules the same in the three cases? If not, in which case is vrms the largest?
At what temperature is the root mean square speed of an atom in an argon gas cylinder equal to the rms speed of a helium gas atom at – 20 °C? (atomic mass of Ar = 39.9 u, of He = 4.0 u).
50 m3 of saturated vapour is cooled down from 30°C to 20°C. Find the mass of the water condensed. The absolute humidity of saturated water vapour is 30 g m−3 at 30°C and 16 g m−3 at 20°C.
What do you understand by gas?
Fill in the blanks:
If the temperature is reduced to half, ………….. would also reduce to half.
Correct the following statement:
0°C is equal to zero Kelvin.
Name or state the following:
An equation used in chemical calculations which gives a simultaneous effect of changes of temperature and pressure on the volume of a given mass of dry gas
Give reason for the following:
Temperature remaining constant the product of the vol. & the press, of a given mass of dry gas is a constant.
The average energy per molecule is proportional to ______
Show that for diatomic gas the ratio of the two specific heats is 7:5.
The equation of state for 2g of oxygen at a pressure 'P' and temperature 'T', when occupying a volume 'V' will be ______.
Three vessels of equal capacity have gases at the same temperature and pressure. The first vessel contains neon (monatomic), the second contains chlorine (diatomic), and the third contains uranium hexafluoride (polyatomic).
Do the vessels contain an equal number of respective molecules?
Which of the following diagrams (Figure) depicts ideal gas behaviour?
 (a) |
 (b) |
 (c) |
 (d) |
A box of 1.00 m3 is filled with nitrogen at 1.50 atm at 300K. The box has a hole of an area 0.010 mm2. How much time is required for the pressure to reduce by 0.10 atm, if the pressure outside is 1 atm.
Cooking gas containers are kept in a lorry moving with uniform speed. The temperature of the gas molecules inside will ______.
