Why are the average atomic masses of some of the elements in parentheses?

At which of the following temperatures is the average kinetic energy of the molecules of a substance the least? 23.2 °C 35.2 °C 15.2 °C 31.4 °C

Which pair of ions can form an ionic bond with each other and why? A) Cu + and Ag+; They are both metal ions. B) S2 - and O2-; They have like charges. C) Br - and At-; They are both halogen ions. D) Li + and Br-; They have unlike charges.

The bohr theory of the hydrogen atom predicts the energy difference (in j) between the n = 3 and the n = 5 state to be

What is the oxidation number of manganese (Mn) in potassium permanganate (KMnO4) ? +3 +5 +6 +7

The density of ethanol was determined experimentally at 25°C in a series of trials to be 0.608 g/mL, 0.705 g/mL, and 0.689 g/mL. The accepted density of ethanol is reported to be 0.789 g/mL. calculate % error for this experiment.

Compare the advantages and disadvantages of using nuclear energy.

Prokaryotes that can cause diseases are in what domain

This metal is very reactive, has properties similar to magnesium, and is in the same period as bromine. What element is this?

Name two ways that living things use proteins

Solid lithium metal and diatomic fluorine gas react spontaneously to form a solid product. give the balanced chemical equation (including phases) that describes this reaction.