how many kilojoules 25.0 are needed to raise the temperature of 550.0 g of water from 25.0 celcius to 75.0 celcius

Harvey mixes two liquids. which observation of the new mixture most likely indicates a precipitate is forming?

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?

Find the mass, in grams, of 5.00*10^23 molecules of f2