The mass of a nickel coin is 5 g.
1 mol of Ni weighs 58 g. 1 mol contains 6.022 x 10²³ atoms of Ni.
therefore in 58 g there are 6.022 x 10²³ atoms of Ni
then in 5 g the number of Ni atoms are - 6.022 x 10²³ /58 x 5 = 5.2 x 10²² Ni atoms
Therefore number of Ni atoms are 5.2 x 10²² atoms in a nickel coin
Answer:
option B is correct.
Y is a mixture in the picture.
Explanation:
Different types of substances combine physically and form a mixture.
Mixture formed by the combination of two or more substances that that combine in same physical state.
For example mixture of copper sulphate and solid chloride in dry form and that will look like white and blue crystal in a mixture.
The picture Z showing dots of same color and is not a mixture, while picture Y shows dots of different colors clearly indicating that it is picture for mixture.
Answer:
Hi. Increased evaporation would be the greatest difference.
Explanation:
Have you ever had a drink in a mug with a lid? When you would remove the lid, all of the liquid on the lid is the liquid that would evaporate if there was no lid.
Answer: 4. 
and 
Explanation:
a) The given reaction is 
As the mass on both reactant and product side must be equal:
As the atomic number on both reactant and product side must be equal:
b) 
Total mass on reactant side = total mass on product side
15 =15 + x
x = 0
Total atomic number on reactant side = total atomic number on product side
8 = 7 + y
y = 1
