Answer: 530 hours
Explanation:
The reduction of Nickel ions to nickel is shown as:
of electricity deposits 1 mole of Nickel
1 mole of Nickel weighs = 58.7 g
Given quantity = 18.0 kg = 18000 g (1kg=1000g)
58.7 g of Nickel is deposited by 193000 C of electricity
18000 g of Nickel is deposited by = 
of electricity
where Q= quantity of electricity in coloumbs = 59182282.8C
I = current in amperes = 31.0 A
t= time in seconds = ?
(1h=3600 sec)
Thus 530 hours are required to plate 18.0 kg of nickel onto the cathode if the current passed through the cell is held constant at 31.0 A
There are three perfect squares in a standard die; 1, 2, 4. If there is two standard dies, then the probability of getting a perfect square is 1/3 x 1/3 = 1/9.
There are 4 numbers less than 5 in a standard die, making it 1/4 x 1/4=1/16.
Answer: The molar mass of each gas
Explanation:
Mole fraction is the ratio of moles of that component to the total moles of solution. Moles of solute is the ratio of given mass to the molar mass.
Suppose if there are three gases A, B and C.
a) 
b) 
c) 
moles of solute =
Thus if mass of each gas is known , we must know the molar mass of each gas to know the moles of each gas.
Answer:
Molar mass
Explanation:
This is a counting unit which represents the mass in grams of a substance that make up one mole of the substance. This mass is calculated as follows:
Molar mass = Mass/ Number of moles
Units: grams/mol
