They can grow fungus and they emit carbon
Balanced chemical reaction:
2Na₃PO₄(aq) + 3CaCl₂(aq) → 6NaCl(aq) + Ca₃(PO₄)₂(s).
Ionic reaction:
6Na⁺(aq) + 2PO₄³⁻(aq) + 3Ca²⁺(aq) + 6Cl⁻(aq) → 6Na⁺(aq) + 6Cl⁻(aq) + Ca₃(PO₄)₂(s).
Net ionic reaction: 2PO₄³⁻(aq) + 3Ca²⁺(aq) → Ca₃(PO₄)₂(s).
<span>(aq) means that
substances are dissociated on cations and anions in water.
</span>(s) means solid.
Answer:
when the red litmus paper is placed in a jar of ammonia, the red litmus paper turns into blue as ammonia gas is basic in nature. It confirms the alkalinity of the ammonia gas.
Resistance of a material being scratched in known as: Hardness
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
