How many total hydrogen molecules are needed for the reaction in #2, so that there are no N2 or H2 left overs

What is a metal replacement reaction

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

Pastoral farming is best described as a. a method of raising livestock and moving herds b. an african method of agriculture c. a method of cultivating crops on poor soils d. a common method of desert farming select the best answer from the choices provided a b c d