How many valence electrons are in potassium

A balloon is inflated with 0.2494g of helium to a pressure of 1.26atm. If the desired volume of the balloon is 1.250L, what must the temperature be in ⁰C?

Which of the following elements is a highly reactive nonmetal? A. iron (Fe) B. sodium (Na) C. flourine (F) D. helium (He)

The change in entropy, Δ?∘rxn, is related to the the change in the number of moles of gas molecules, Δ? gas.

Na2CO3 + CO2 + H2O → NaHCO3 1. Which of the following coefficients would correctly balance the chemical reaction shown above? A. 1,2,3,4 B. 1,1,1,2 C. 2,1,1,1 D. 2,2,3,1

What does the 3 indicate in 1s22s22p63s1

Two gas jars are connected to each other, but they are separated by a closed valve. One gas jar contains oxygen, and the other is empty. What will happen when the valve is opened?

4. Calculate the final concentration if water is added to 1.5 L of a 12 M NaOH solution to make 3.0 L of a diluted NaOH solution. Your answer

Why is it possible to safely drink a solution that contains a 50:50 mixture of equal concentrations of a strong acid and a strong base, either of which, if ingested separately, would be very caustic and damaging?

Explain why many compounds that contain one or more hydrogen atoms are not classified as arrhenius acids

pure substance x is a green powder. when heated, it gives off a gas and changes to a black powder. is substance x an element or a compound? give reasons