Answer:
copper(ll) carbonate
Explanation:
Since the product is a salt which is copper(II) carbonate, water and carbon dioxide, this reaction is an acid + metal carbonate reaction.
Looking at the salt, Cu²⁺ has to be part of the reactants.
Hence, the missing compound there has to be copper(ll) carbonate, CuCO₃.
The balanced chemical equation would be:
CuCO₃ + 2HNO₃➙ Cu(NO₃)₂ +H₂O +CO₂
P.s. You left out CO₂ as a product in Q2 ;)
Just a recap of the main reactions you would've learnt:
1) Acid + base/ alkali ➙ salt + water
2) Acid + metal ➙ salt + hydrogen gas
3) Acid + metal carbonate ➙ salt + H₂O + CO₂
1.7960L
Explanation:
the mass of the gas is constant in both instances
pv/T=constant(according to pv=nRT)
745mmHg*2L/298K=760mmHg*v/273K
v=1.7960L
Answer:- The natural abundance of 
is 0.478 or 47.8% and 
is 0.522 or 52.2% .
Solution:- Average atomic mass of an element is calculated from the atomic masses of it's isotopes and their abundances using the formula:
Average atomic mass = mass of first isotope(abundance) + mass of second isotope(abundance)
We have been given with atomic masses for and as 150.919860 and 152.921243 amu, respectively. Average atomic mass of Eu is 151.964 amu.
Sum of natural abundances of isotopes of an element is always 1. If we assume the abundance of as n then the abundance of would be 1-n .
Let's plug in the values in the formula:
151.964=150.919860n+152.921243-152.921243n
on keeping similar terms on same side:
negative sign is on both sides so it is canceled:
The abundance of is 0.478 which is 47.8%.
The abundance of is = 
= 0.522 which is 52.2%
Hence, the natural abundance of is 0.478 or 47.8% and is 0.522 or 52.2% .
