Rust on a nail is a chemical change.
Ice melting IS a physical change. Ice is made of water, when you melt ice its still water. Just in a different physical state.
Answer:
B.
Explanation:
This is physical change as the popcorn has expanded in size.
Answer:
O2 is limiting reactant
Explanation:
To find the limiting reactant we need to convert the mass of each reactant to the moles using the formula weight. And, as 1 mole of C6H12O6 reacts with 6 moles of O2, we can know wich reactant will be over first (Limiting reactant) as follows:
<em>Moles C6H12O6:</em>
650g * (1mol/180.16g) = 3.608 moles C6H12O6
<em>Moles O2:</em>
650g * (1mol/32g) = 20.31 moles O2
Now, for a complete reaction of 3.608 moles of C6H12O6 are required:
3.608 moles C6H12O6 * (6mol O2 / 1mol C6H12O6) = 21.65 moles O2
As there are just 20.31 moles of O2,
<h3>O2 is limiting reactant</h3>
Answer:
4 moles of H₃PO₄
Explanation:
The reaction expression is given as;
3KOH + H₃PO₄ → K₃PO₄ + 3H₂O
Number of moles of water = 12moles
Unknown:
Number of moles of H₃PO₄ = ?
Solution:
From the balanced reaction expression we see that;
3 moles of water is produced from 1 mole of H₃PO₄
So; 12 moles of water would be produced from 
= 4 moles of H₃PO₄
