Answer:
mass= 14kg
Explanation:
density= mass/volume
so that means mass= volume x density
m= 2kg/m³ x 7m³
m= 14 kg
Hope this helps
Answer: 
Explanation:
Firstly we need to know that
, then we cam make the conversion:
This is the height of Mount Everest in feet
However, we can express it using scientific notation by counting to the left the decimal spaces:

Answer:
Oxygen is the most contain in earth but you asked in a,b,c and d. So I'll choice A. aluminium.
Hey there!:
HCl + MnO2 → MnCl2 + H2O + Cl2
* in HCl the oxidation state of Cl is -1 .
* on the product side the oxidation state is 0 .
* therefore Cl gains electrons .
* in MnO2 the oxidation state of Mn is +4
* in MnCl2 the oxidation state of Mn is +2
Therefore Mn loses electrons
Answer A
Hope That helps!