How many molecules are there in 0.250 moles of sodium hydroxide

The diagram below shows a cell placed in a solution.a cell is shown placed inside a beaker. it is labeled cell. the solution inside the beaker is labeled 40% salt solution and the solution inside the cell is labeled 20% salt solution.only water is allowed to move in and out of the cell. what will most likely happen to the cell? it will expand as water moves out of it. it will shrink as water moves out of it.it will expand as water moves into it. it will shrink as water moves into it.

As changes in energy levels of electrons increase, the frequencies of atomic line spectra they emit

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.)