You can change any variable in an experiment (the amount of water, sun, type of light, fertilizer etc.) but for the experiment to be VALID only one thing can be changed for the experiment.
Example: I’m trying to see if the plant will grow better with more or less water so the only thing that changes is the amount of water. Everything else will have to be the same (type of plant, fertilizer,dirt, container it grows in, amount of light etc.)
Tides are the rise and fall of the oceans. They are caused by the gravity, or pull, of the Moon and Sun. The Moon's gravity is the main force in causing tides. It makes the oceans bulge out toward it. Another bulge occurs on the opposite side, because Earth is being pulled toward the Moon and away from the water. The water on the side farthest away from the Moon is least affected by its gravity.
Answer:
2 moles H
2
Explanation:
Your tool of choice here will be the mole ratio that exists between zinc metal,
Zn
, and hydrochloric acid,
:HCl
, in the balanced chemical equation.
Zn
(s]
+
2
HCl
(aq]
→
ZnCl
2(aq]
+
H
2(g]
↑
⏐
You're dealing with a single replacement reaction in which zinc displaces the hydrogen from hydrochloric acid. The products of the reaction are aqueous zinc chloride and hydrogen gas.
Now, as you can see from the balance chemical equation, a
1
:
2
mole ratio exists between the two reactants.
This tells you that in order for the reaction to take place, you need to have twice as many moles of hydrochloric acid as you do of zinc metal.
http://people.springfield.k12.or.us/jim.tyser/chemcom/Resources/unit1ans.html
http://people.springfield.k12.or.us/jim.tyser/chemcom/Resources/unit1ans.html
At the same time, you have a
2
:
1
mole ratio between hydrochloric acid and hydrogen gas.
This means that the reaction will always produce half as many moles of hydrogen gas as you have moles of hydrochloric acid.
Since you know that
4
moles of hydrochloric acid are taking part in the reaction, and assuming that you have enough zinc metal so that it doesn't act as a limiting reagent, you can say that the reaction will produce
4
moles HCl
⋅
1 mole H
2
2
moles HCl
=
2 moles H
2
Explanation: