In a chemical reaction one or more reactants combine or react to form one or more product(s) with different chemical and physical properties.
When aqueous sodium sulfide reacts with aqueous copper(II) nitrate results in the formation of aqueous sodium nitrate and solid copper(ll) sulfide.
First, identify the chemical symbols for the elements in the compounds.
Sodium sulphide = 
Copper(II) nitrate = 
Sodium nitrate = 
Copper(II) sulfide = 
The chemical reaction is given as:

Now, balance the chemical equation:
For balance the equation, multiply
by 2.
Thus,

Not sure about P4S5, but CH4 is Methane, NF3 is Nitrogen trifluoride, and N2O is Nitrous oxide.
Answer:
(1) 25.0cal/g (2) 540cal/g (3) 327 cal/g (4) 8,180 cal/g 82 If 11 grams of a gas occupies 5.6 liters at STP, what is its gram molecular mass? (1) 11 g/mol (2) 22 g/mol