Answer: 
Explanation:-
Single replacement reaction is a chemical reaction in which more reactive element displaces the less reactive element from its salt solution.
As zinc is more reactive than copper, it could easily displace copper from its aqueous solution and thus leads to formation of zinc (II) sulfate and pure copper.
The chemical reaction can be represented as :

The phases are represented as (s) for solid sate, (l) for liquid state, (g) for gaseous state and (aq) for aqueous state.
Answer:
The volume of the second cylinder is 80 liters
Explanation:
We use the Boyle-Mariotte formula, according to which the pressure and volume of a gas are inversely related, keeping the temperature constant: P1 x V1 = P2xV2. We convert the pressure in mmHg to atm:
760 mmHg-----1 atm
380mmHg------x= (380mmHgx1atm)/760mmHg=0,5 atm
P1xV1=P2xV2
2 atmx20 L= 0,5atm x V2 V2=(2 atmx20 L)/0,5atm=80L
Answer:
The precipitate was chromium hydroxide, which then reacted with more hydroxide to produce a soluble complex, Cr(OH)4
Explanation:
The following reaction takes place when chromium(III) nitrate reacts with NaOH:
+3 NaOH →
(s)+ 
The precipitate that is formed is chromium hydroxide, 
When more NaOH is added, the precipitate reacts with it which then results in the formation of a soluble complex ion:
(s) +
(aq) →
(aq)
is soluble complex ion
Carbon -13 has 7 neutrons and carbon -12 has six neutrons. Carbon -12 is the most common isotope of Carbon. Carbon -14 is radioactive and vary rare. The symbols for the isotopes of Carbon atoms shown here indicate they each have six protons but mass numbers of 14, 13, and 12. Hope this helps. :)

dissolves in water to give

and

ions according to the following reaction:

-------->

+ 2

So, according to the above reaction, 1 mole of

produce 2 moles of

ion,
So, 0.3 mole will give = 0.3 x 2 = 0.6 moles of

ion
So, Molar concentration =

Note: 1L = 1000mL