Scientists have hypothesized that oxygen began to build up in the Earth's atmosphere after the development of living things with the ability to

a. breathe air.

b. form tissues.

c. photosynthesize.

d. reproduce sexually.

Calculate q (in units of joules) when 1.850 g of water is heated from 22 °C to 33 °C

How many isomers with a molecular formula of c6h10 contain an internal alkyne?

Who wants to talk to a complete stranger

Which ions produce similar colors in the flame tests?

What is the atomic number of zirconium? 39 40 41 42

Luis set a glass of ice water out side is the sunshine. when he looked at the glass 10 minutes later, the contents had changed. what kind of change happened to the ice water? A. evaperation B. conduction C. chemical change d. sudden change

A substance is considered to have a smaller surface area when ... A. it is a fine powder B. it is in large chunks C. you have a small amount of the substance D. you have a large amount of E. the substance

Which is the noble gas notation for chlorine? A-[Ne] 4s2 4p5 B-[Ne] 3s2 3p5 C-[Ne] 3s2 3p3 D-[Ne] 3p2 3p5

Is argon long hand or noble gas

Lithium, beryllium, and boron are elements with atomic number 3, 4, and 5, respectively. Even though they are three of the five simplest elements, why are they rare compared to many heavier elements?