Why does every element except hydrogen need at least one neutron in its nucleus?

If the solubility of a gas in water is 4.0 g/l when the pressure of the gas above the water is 3.0 atm, what is the pressure of the gas above the water when the solubility of the gas is 1.0 g/l? 4.0 atm 1.3 atm 0.75 atm 12 atm

A substance undergoes a change. Which of the following indicates that the change was a chemical change? The substance froze The substance changed size The substanced changed shape New molecules formed

How manhhy neutrons does element x have if its atomic number is 24 and its mass number is 77?

What type of bond is most likely to be formed between two fluorine atoms? An ionic bond a nonpolar covalent bond a polar covalent bond a hydrogen bond

Where does the energy given off by an exothermic reaction come from? A. The chemicals make the energy during the reaction from atoms that are consumed. B. The atoms in the air are converted to energy during the explosion. C.

Hydrochloric acid is purchased in 12 molar concentrations. If I needed 200 ml of 2.0 molar HCl, how many milliliters of the concentrated solution would I need

Which of the following represents a chemical change? Bending a wire Freezing of water Fireworks exploding Melting of a wax candle

5.00 L of a gas is collected at 100K and then allowed to expand to 20.0 L. What must the new temperature be in order to maintain the same pressure? A. 400 °C B. 127 °C C. 223 °C D. 627°C

Before the initial explosion was the matter hot or cold

Which of the following atoms has seven valence electrons? chlorine (Cl) nitrogen (N) manganese (Mn) oxygen (O)