12.01 amu
Work:
(12.000 × .9889) + (13.003 × .0111) = 12.01
- turn the precents into decimals
The question is incomplete, the complete question is;
Experiments were done on a certain pure substance X to determine some of its properties. There's a description of each experiment in the table below. In each case, decide whether the property measured was a chemical or physical property of X, if you can. If you don't have enough information to decide, choose can't decide in the third column. property experiment physical or chemical? Х O physical 0 A sample of solid X is carefully weighed and put inside a vented flask. The flask is heated until oxygen gas starts being produced. After no more oxygen gas is produced, the contents of the flask are removed and weighed, and from the decrease in weight the value of O may be calculated. O chemical O (can't decide) O physical V A sample of X is melted and put into a reservoir from which a very thin tube leads down. The rate at which X flows out of the tube is measured, and from this rate the value of V may be calculated. chemical (can't decide) O physical Q A sample of solid X is carefully weighed and put inside a sealed flask. Pure hydrogen gas is added to the flask, and the mixture heated until the hydrogen starts being consumed. After hydrogen stops being consumed, the contents of the flask are removed and weighed, and from the increase in weight the value of may be calculated. O chemical O (can't decide)
The decisions that should be made are;
1) Chemical property
2) Physical property
3) Chemical property
A chemical property is one in which atoms of a substances are rearranged in the process. In the first case, the substance was heated and oxygen was produced. This is a decomposition reaction hence it is a chemical property that is being measured.
In the second case, the molten substance is made to flow and the flow rate is measured. The flow rate of a substance is a physical property.
In the third case, hydrogen combines with an element in the flask. This is a chemical property.
Learn more; brainly.com/question/6284546
There are 6.022*10^23 molecules in 1 mole of carbon
So how many will moles will be 7.87*20^7?
Let the required number of moles be ‘x’.
1 mole ———6.022*10^23
x moles———7.87*10^7
(Cross multiplication)
x=7.87*10^7/6.022*10^23
Therefore x=1.3*10^-16
