Answer: 1: B. It will speed up the reaction.
2: A. Increase the concentration of a reactant.
3: A. They act as catalysts.
4: C. A catalyst decreases the activation energy needed for a reaction.
5: D. collision theory.
Explanation: I just took the quiz:)
A chemical change produces a new substances. Examples of chemical changes are burning a cooking egg
Answer:
B
Explanation:
Acid rain
damaging a marble statue or anything else
is a physical change. <3
Answer:
7.5 moles
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
3Cu + 2H3PO4 —> Cu3(PO4)2 + 3H2
From the balanced equation above,
3 moles of Cu reacted with 2 moles of H3PO4.
Therefore, Xmol of Cu will react with 5 moles of H3PO4 i.e
Xmol of Cu = (3 x 5)/2
Xmol of Cu = 7.5 moles
Therefore, 7.5 moles of Cu are needed to react with 5 moles of H3PO4.
Remember that density refers to the "mass per unit volume" of an object.
So, if an object had a mass of 100 grams and a volume of 100 milliliters, the density would be 100 grams / 100 ml.
In the question, water on the surface of the scale would add weight, so the mass of the object that you're weighing would appear to be heavier than it really is. If that happens, you'll incorrectly assume that the density is GREATER than it really is
As an example, suppose that there was 5 ml of water on the surface of the scale. Water has a density of 1 gram per milliliter (1 g/ml) so the water would add 5 grams to the object's weight. If we use the example above, the mass of the object would seem to be 105 grams, rather than 100 grams. So, you would calculate:
density = mass / volume
density = 105 grams / 100 ml
density = 1.05 g/ml
The effect on density would be that it would erroneously appear to be greater
Hope this helps!
Good luck
