1:2
The ratio of carbon, hydrogen, and oxygen in most carbohydrates is 1:2:1. This means for every one carbon atom there are two hydrogen atoms and one...
For very large numbers, it is much more convenient to use scientific notation. To do this, detect first the position of the decimal point. For whole numbers, the decimal point is place implicitly after the very last digit. Then, move this decimal point to the left until you reach to the last digit. In this case, you moved 8 places until you reach 6.4. Because the number is more than 1, the exponent would have a positive sign. Hence, the scientific notation would be 6.4×10⁸.
The correct answer is + 32.5 J because heat is absorbed here by copper not evolved also after calculation we will find the H value is positive, lets calculate it:
H = m C Δt where:
m = 10 g
C = 0.13 J/g.°C
Δ t = final temperature - initial temperature = 50 - 25 = + 25 °C
so H = 10 x 0.13 x (+25) = + 32.5 J
