25 g of a chemical is dissolved in 75 g of water. What is the percent by mass concentration of this chemical

Explain which atom l or m is more stable and why

An atom of lithium-7 has an equal number of(1) electrons and neutrons(2) electrons and protons(3) positrons and neutrons(4) positrons and protons

As air becomes more dense, (select all that apply) o. air weighs less o. gas molecules are closer together o. air is colder o. air weighs more o. gas molecules are further apart o. air is hotter