How does a catalyst affect chemical change?
a. catalysts do not cause chemical changes
c. by slowing down a chemical reaction
b. by speeding up a chemical reaction
d. none of the above

An atom of lithium-7 has an equal number of(1) electrons and neutrons(2) electrons and protons(3) positrons and neutrons(4) positrons and protons

In salt water solution,the salt is the blank

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.