Answer:
Explanation:
it is very important because with out it we will die
Answer:
Mass = 17.8 g
Explanation:
Given data:
Number of atoms of Ca = 2.68 × 10²³
Mass in gram = ?
Solution:
Avogadro number:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
2.68 × 10²³ atoms × 1 mole /6.022 × 10²³ atoms
0.445 mol
Mass in gram;
Mass = number of moles × molar mass
Mass = 0.445 mol × 40 g/mol
Mass = 17.8 g
Answer:
D
Explanation:
Lungs, Moist skin , Gills is in the exchange of gases system
Answer: b
Explanation: alpha decay or particle consist of two protons and two neutrons hence it is a helium nucleus.
The causes of mass extinction
As there might be marks on fossils showing the suffering that happened to it!
