Answer is B.
Explanation:
A physical change is one in which there is no change in chemical composition of a substance. while a process in which there is change in chemical composition it is called a chemical change.
Answer:
After the transfer the pressure inside the 20 L vessel is 0.6 atm.
Explanation:
Considering O2 as an ideal gas, it is at an initial state (1) with V1 = 3L and P1 = 4 atm. And a final state (2) with V2 = 20L. The temperature remain constant at all the process, thus here applies the Boyle-Mariotte law. This law establishes that at a constant temperature an ideal gas the relationship between pressure and volume remain constant at all time:

Therefore, for this problem the step by step explanation is:

Clearing P2 and replacing

Answer:
2Cu2S + 3O2 + 2C -------> 4Cu + 2SO2 + 2CO
Explanation:
Equation 1 should correctly be written as;
2Cu2S + 3O2-----> 2Cu2O + 2SO2
Equation 2 should be correctly written as;
2Cu2O + 2C -----> 4Cu + 2CO
The overall reaction equation is;
2Cu2S + 3O2 + 2C -------> 4Cu + 2SO2 + 2CO
Note that species that are intermediates are cancelled out .
The answer is bohr hope this helps :)