If two objects at different te, peraure are in contact with each other what happens to their temperature

If i make a solution by adding 83grams of sodium hydroxide to 750ml i’d water what is the molarity of sodium hydroxide

Which sentence about particles in matter is true? a. atoms are present in solids and liquids but not in gases. b. the particles of matter are in constant motion. c. the same kinds of atoms are found in different elements. d. when a solid changes to a liquid, the sizes of the particles change.

If 16.00g of hydrogen gas reacts with 126.73g of oxygen, how many grams of water are yielded? (both reactants are completely consumed in the reaction.)