12. (01.06 LC) Which of the following is a property of a pure substance? (5 points)
It consists of different types of compounds.
It may have substances in different states of matter,
It is made up of a single element or type of compound,
Its components can be separated by employing physical methods.

Ibeg i need 20. a reaction produces 4.93 l of oxygen, but was supposed to produce 1 mol of oxygen. what is the percent yield?

Compare and contrast refraction of light and sound will give brainliest

The yearly amounts of carbon emissions from cars in belgium are normally distributed with a mean of 13.9 gigagrams per year and a standard deviation of 5.8 gigagrams per year. find the probability that the amount of carbon emissions from cars in belgium for a randomly selected year are between 11.5 gigagrams and 14.0 gigagrams per year. a. 0.340 b. 0.660 c. 0.167 d. 0.397