Weight is derived from which quantity?​

According to the law of conservation of mass, in a chemical reaction the total starting mass of all the reactants equal the total final mass of all the products. true or false?

Alice added sodium chloride to water and stirred the water for several minutes. alice is most likely trying to demonstrate that ionic compounds a. are hard. b. can dissolve. c. are clear. d. can melt.

The boy of mass 30 kg is at r1= 2 meters from the fulcrum. of the girl is 45 kg, at what r2 must she sit so that they are balanced ?