Determine the number of moles of phosphine gas that is formed when hydrogen gas reacts with phosphorus (at STP) to form 15.3 g of phosphine (PH3). (molar masses: P = 30.97g/mol, H = 1.01g/mol)

Asolution of sodium hydroxide was titrated against a solution of sulfuric acid. how many moles of sodium hydroxide would react with 1 mole of sulfuric acid?

Aglow stick contains a glass vial with chemicals. when the glow stick is bent, the vial breaks and the chemicals react to produce a glow. a science student observes that a glow stick kept in the freezer glows for a longer duration than a glow stick kept at room temperature. what conclusion can be drawn based on the observation? be sure to note the outcome and test variables in the conclusion.

Two metal blocks that have slightly different temperatures are placed next to one another. after five minutes, they both have lower but equal temperatures. according to the law of conservation of energy, what  most likelyhappened? energy was created inside the blocks. energy was destroyed inside the blocks. energy was absorbed into the blocks from outside the system. energy was transferred from the warmer block to the cooler block.