So, you need to have same ammount of atoms on the left and on the right side of the equation. You need to count the ammount of attoms of every substance on the left, and make sure that on the right side the ammount is same. For example in the 1st one it’s 6Sn+2P4=2Sn3P4, so that you have 6atoms of Sn on the left and 6 atoms of Sn on the right, same with the P
Divide the mass of the compound in grams by the molar mass you just calculated. The answer is the number of moles of that mass of compound. For example, 25 grams of water equals 25/18.016 or 1.39 moles.
Take a zip lock bag and draw clouds on the outside with a sharpie then fill the bag with water and then tape it on a window that has a lot of sun and wait awhile and there should be a change in the water and that shooed what happens to water when it’s warm/sunny out
I would have to say the answer is a. True.