Help I’m not sure what to do

According to each substances heat of fusion, which of the items below requires more heat to be added per gram of substance to go from solid to liquid? silver sulfur water lead

In the reaction between a crushed antacid tablet and vinegar what gas is emitted

What rule is used to determine how many covalent bonds an element can form? a. the number of covalent bonds is equal to six c the number of covalent bonds is equal to five minus the group number plus the group number b. the number of covalent bonds is equal to eight d. none of the above minus the group number select the best answer from the choices provided