Classical physics that matter cannot be created or destroyed in an isolated <span>system</span>
Answer:
there is no question to answer :(
Explanation:
(a) The mass of an object remains the same always. It is independent of its location. In this case, an iron nail is ground into powder. It means that its mass will remain unchanged. Hence, (a) is the correct option.
(b) Whenever there is a change of color of an object, a chemical reaction occurs. It shows that a reaction happens there. In this problem, a paper turns yellow-brown upon exposure to sunlight. A chemical reaction takes place there. Hence, (b) is the correct option.
Answer:
480 g of oxygen.
Explanation:
C3H8 + 5O2 ---> 3CO2 + 4H2O
Using the molar masses:
3*12 + 6*16 g of CO2 were formed from 10*16 g O2
132g g CO2 from 160 g O2
1g CO2 from (160/132) g O2
396 g from (160/132) * 396
= 480 g of oxygen.