Answer:
Sodium citrate is a compound with a total of 21 atoms
6a. physical reaction
6b. endothermic reaction
7a. physical reaction
7b. the reactants are carbon dioxide, water and light energy. the product is starch
7c. exothermic reaction
Wireless devices, wi-fi routers, granite countertops, microwaves, cigarettes (if you smoke in your house), older box-shaped tv’s, antiques (furniture, jewelry, silverware), smoke detectors ( some use small amounts of radioactive isotope, americium-241 to alert you when there’s smoke in the air, light bulbs, computer screens, electric blankets, garage door openers. Hope it helps.