You are required to prepare a 250 mL sample of a 0.20 mol/L solution of sodium chloride. Calculate the mass of solute required to make this solution. This is your stock solution.

Sally is making a model of a magnesium atom with an atomic mass number of 24 for her chemistry class. she has foam balls for the protons, neutrons, and electrons. she has added 6 neutrons to her model so far. how many more neutrons does she need to add to complete her neutral atom of magnesium?

How much heat is added if 0.814g of water increase in temperature by 0.351 degree c?

Abaker touches a pie right after taking it out of the oven. which statement best explains why the pie feels hot?