Hydrogen is a pure substance represented by chemical symbol H. which of the following best describes hydrogen?

Is crushing a rock a chemical or physical change?

Which statement best describes the trend in atomic radii observed in the periodic table? 1. The atomic radii increase, moving across a period to the right and up in a group. 2.

What is the formula for manganese (IV) dioxide

Why do you think that if you drop two balls, exactly two balls rise on the other side at a similar speed? Why doesn't one ball fly off quickly instead? Why don't three balls fly off slowly?

Boyle's law states that the a. volume of a gas varies inversely with pressure. b. volume of a gas varies directly with pressure. c. temperature of a gas varies inversely with pressure. d. temperature of a gas varies directly with pressure.

In the synthesis reaction, the white powder produced is magnesium oxide (mgo, mm = 40.3 g/mol). how many moles of magnesium oxide were formed (number of moles = mass (g) / molar mass (g/mol)) ? choose the closest answer. a. 0.21 moles b. 0.

Which of the following is the most likeley example of an favorable mutation A. A mutation that makes a rabbit able run faster B. A mutation that changes the rabbit's fur to bright orange C. A mutation that changes the color of the rabbit's eyes D.

Which of these mole ratios is possible for this reaction? FeCl3 + 3NaOH → Fe (OH) 3 + 3NaCl 1:1 1:3 3:1 2:3

The chemical equation for reduction of phosphorite Ca3 (PO4) 2

Synthesize What environmental effects are shared by all fossil fuels?