What are the symbol, name, and atomic number of the element that has 21 protons in the nuclei of its atoms?

The appropriate unit for a first order rate constant are

1. Methane (CHA) gas diffuses through air because the molecules are

How many moles of aluminum do 4.60x10^24 aluminum represent? Express your answer using three significant figures.

If the Density of an object is 5.2 g/cm 3, and its volume is 3.7 cm 3, what is its mass?

How many shells and valence electrons does radon have?

2NO + O2 → 2NO2 What type of chemical reaction is shown above? a combustion reaction b double displacement C synthesis d decomposition e single displacement

Why did Bromophenal solutions change from yellow to blue (what chemical reaction happended) ?

How many milliliters of calcium, with a density of 1.55 g/mL, are needed to produce 85.8 grams of calcium fluoride in the single replacement reaction below? Show all steps of your calculation as well as the final answer.

If object A is placed on the pH scale at pH = 3 and object B is placed at pH = 8, which of the following must not be true? A. Object B has a higher hydroxide ion concentration than object A. B. Object B is closer to a neutral pH than object A. C.

Laboratory safety is not an important concern for scientists. True or false