Answer:
Copper is more reactive and higher in the activity series
Explanation:
Copper is able to replace the silver in a replacement reaction because it is more reactive and higher in the activity series.
Substances or ions that are higher in the activity series are typically more reactive than those ones below them.
In like manner, they are able to replace the lowers ones in a chemical reaction due to their higher reactivity potential.
A less reactive element and a lower one in the activity series cannot displace a higher one in the series.
I think its 3 precipitation.
Answer:
Yes
Explanation:
First remember that a significant figure are basically values that contribute to the precision of a value. In any scientific notation the values are significant figures because these values stay the same. In this case we have two significant figures which is 6 and 0, you can further prove that they are significant figures by converting the notation into standard form.

Negative so move the decimal point to the left:

6 and 0 are the significant figures in this standard notation because it's precise to it's actual value which is 6.0.
To sum up, the values you have on the left side of a notation are significant figures since they will not change no matter if it's standard or scientific notation meaning it's precise.
Hope this helps.
Answer:
B) high temperatures increase the activation energy of a reaction.
Explanation:
Ammonia is formed when the nitrogen gas is combined with hydrogen gas in a very high temperature. The high temperature increases the activation energy and nitrogen atom make chemical bonds with hydrogen atom results in the production of ammonia. At room temperature, they cannot react with each other.