(sample g/1) X (1 mole/40.078(MW of Ca)) = moles of sample (moles of sample)(6.022 x 10^23( no of atoms)/ 1 mole) = # of atoms in a 120 g sample of calcium Avogadro's number=6.022x 10^23 atoms in 1 mole
Answer: 
Explanation:
A single displacement reaction is one in which a more reactive element displaces a less reactive element from its salt solution. Thus one element should be different from another element.

Synthesis reaction is defined as the reaction where substances combine in their elemental state to form a single compound.
Decomposition reaction is defined as the reaction where a single substance breaks down into two or more simpler substances.

Combustion is a type of chemical reaction in which hydrocarbons burn in the presence of oxygen to form carbon dioxide and water along with heat.

Answer:
I believe the answer is A (changes in air temperature result in differences in air pressure which causes wind). Hope this helps
Explanation:
Answer:
1. How do metals and non-metals react with acids?
Ans : Non metals does not react with acids while metals react with acids and produce hydrogen gas that burns with a 'pop'sound.
2. Write and explain the chemical equation for the reaction of magnesium with sulphuric acid and aluminium with hydrochloric acid.
Magnesium + sulphuric acid = Hydrogen + salt
Mg(s) + H2SO4 (aq) MgSO 4(aq) +H2 (g)
Aluminium + Hydrochloric acid = Hydrogen + Aluminium chloride
2Al(s)+6HCl(aq)→2AlCl3(aq)+3H2(g)