Answer:
(1) 720 seconds (2) 10800 seconds (3) 17 dozens (4) 1.45 x 
(5) 13.29 moles
Explanation:
(1) 720 seconds
1 minute = 60 seconds
12 minutes = 720 seconds (12 x 60)
(2) 10800 seconds
1 hour = 60 minutes 1 minute = 60 seconds
3 x 60 = 180 minutes in 3 hours
180 x 60 = 10800 seconds in 180 minutes that are in 3 hours
(3) 17 dozens
1 dozen = 12
204 ÷ 12 = 17 dozens
(4) 1.45 x
8.00 moles CO2 x 
= 24.0 moles atoms
24.0 moles x 
= 1.45 x
(5) 13.29 moles
sorry but I'm not fully sure if this one is correct
8 x 
x 
= 13.29 moles
Well I don’t know how you can “bake” a desert but if you can, try to not mix up the sugar and sand
The answer is b) similar chemical properties but very different atomic numbers
Answer:
1. a = 2, b = 1 and c = 2
2. a = 1, b = 3, c = 2 and d = 2
Explanation:
According to law of conservation of mass, the mass can neither be created nor destroyed.
Hence, for a chemical equation the left hand side should be equal to the right hand side.
Therefore, the two balanced equations are;
2 CO + O₂ → 2 CO₂
C₂H₄ + 3 O₂ → 2 CO₂ + 2 H₂O
The maximum percent of yield should be 100%, so It wasn't possible to make a higher than 100% yield like 105% in this problem. If that happens, it will contradict the law of conservation of energy as you can't create mass.
The increased mass might be produced by impurities. One of the examples would be if you rinse the container and left some water. The water is not calculated as a substrate but will increase the results weight.
There also possibilities that some gas in the air react and produce a solid/liquid material. If you don't weight the gas it would seem that the mass increased.
