Answer: 3.0 moles of water
are needed to react with a mole of 3.0 of Na
Explanation:
The balanced chemical reaction of sodium with water is as follows:

According to stoichiometry:
2 moles of sodium
reacts with = 2 moles of water 
Thus 3.0 moles of sodium
reacts with =
moles of water 
3.0 moles of water
are needed to react with a mole of 3.0 of Na
Answer:
3rd option. 1–butanamine
Explanation:
To name the compound above, the following must be observed:
1. Locate the functional group in the chain. In this case the functional group is amine.
2. Locate the longest continuous carbon chain. This gives the parent name of the compound. In this case, the longest chain has 4 carbon i.e butane.
3. Since the functional group is amine, the parent name becomes butanamine i.e replacing the –e at the end in butane with –amine
4. Indicate the position of the functional group in the chain. In this case the functional group is at carbon 1
5. Name the compound by putting the above together.
The name of the compound is:
1–butanamine or butan–1–amine
Answer:
Percentage of copper = 88%
Explanation:
Given data:
Mass of copper = 51.2 g
Mass of tin = 6.84 g
Percentage of copper = ?
Solution:
Formula:
Percentage of copper = mass of copper / total mass × 100
Now we will determine the total mass:
Total mass = mass of copper + mass of tin
Total mass = 51.2 g + 6.84 g
Total mass = 58.04 g
Now we will calculate the percentage of copper.
Percentage of copper = 51.2 g / 58.04 g × 100
Percentage of copper = 0.88 × 100
Percentage of copper = 88%
Mass is always conserved in a physical change. Energy may be released or absorbed when a substance changes from one physical state to another. In a chemical change, a chemical reaction yields a completely new substance. A substance's particles are changed during a chemical reaction.
In a <u>Saturated </u>solution, the rate of dissociation equal to the rate of crystallization
Explanation:
A saturated solution is one than cannot dissolve any more solute because the solutes inter-molecular spaces are filled with the solute molecules at that temperature. When an attempt is made to dissolve more solute into the solution, the rate at which the solute is dissolved into the solution is equal to the rate at which excess solute is precipitated and crystallized.