Which pair must represent atoms of the same element?

Which of these is outside the solar system A nebula B asteroid belt

Atoms become excited when they are heated by a flame. How do atoms return from an excited state to a ground state? A. by emitting a photon of light B. by absorbing a photon of light C. by gaining an electron from another atom D.

Magnesium chloride, mgcl2 (s) reacts with water vapor to form magnesium oxide, mgo (s) and hcl ( g. what is the balanced chemical equation for this reaction?

A dark brown binary compound contains oxygen and a metal. It is 13.38% oxygen by mass. Heating it moderately drives off some of the oxygen and gives a red binary compound that is 9.334% oxygen by mass.

To be considered acid rain, precipitation would have to -contain a lot of carbon dioxide -have a pH of less than 5.6 -contain chlorofluorocarbons -occur in an industrial area

What is the symbol for the second most common element in the universe? a. H b. C c. Fe d. He?

Which class of organic compound would neutralize a carboxylic acid? O aldehyde amine alkyl halide ether

Calculate the molarity of the solution. 29 g of NaCl (g. f. w. = 58.5 g/mol) in 0.030 liters. 0.015 M 17 M 67 M

How can scientists study the composition of distant stars?

When an ionic compound such as sodium chloride (NaCl) is placed in water, the component atoms of the NaCl crystal dissociate into individual sodium ions (Na+) and chloride ions (Cl-). In contrast, the atoms of covalently bonded molecules (e. g.