The mass of piece of sterling silver jewelry is 33.24 g. It contains 92.5% silver Ag by mass. Since, sterling silver is an alloy of Ag-Cu thus, percentage of Cu will be:
% Cu=100-92.5=7.5%
Thus, mass of copper will be:
Molar mass of Cu is 63.546 g/mol, thus, number of moles of Cu can be calculated as follows:
Here, m is mass and M is molar mass.
Putting the values,
Now, in 1 mole of Cu there are 
thus, in 0.03923 mol, number of Cu atoms will be:
Thus, number of atoms of Cu will be
.
Answer:
P = 2.145kPa
Explanation:
Mass = 22.1g
Molar mass of CO2 = 44g/mol
Vol = 165mL = 0.165L
T = -188°C = (-188 + 273.15)K = 85.15K
R = 8.314J/mol.K
From ideal gas equation,
PV = nRT
P = pressure of the ideal gas
V = volume the gas occupies
n = number of moles if the gas
R = ideal gas constant
T = temperature of the gas
n = number of moles
n = mass / molar mass
n = 22.1 / 44 = 0.50moles
PV = nRT
P = nRT/ V
P = (0.5 × 8.314 × 85.15) / 0.165
P = 2145.26Pa = 2.145kPa
Pressure of the gas is 2.145kPa
Answer:
Step-by-step explanation: We are asked to find the distance covered by a man in 15 minutes at a speed of 16 km/hr. 15 minutes = 15/60 hour. Therefore, the person can run 4 km in 15 minutes.
Explanation:
