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
A) releasing CO2 that dissolves and forms acid in the oceans (i think i'm sorry if its wrong)
Answer:
~1.5 g/cm3 and it does NOT float in water.
Explanation:
If you look at the graph, Object A weighs ~6 grams and is ~4 cm3 in volume
Density = Mass/Volume
So 6 grams/4 cm3 = 1.5 g/cm3
Water has a density of 1 g/cm3 and because Object A density is higher than that of water, it sinks.
:)
