Students A and B mix two solutions together during a lab investigation. Both students observe a temperature change and a production of gas being emitted. Student A concludes that there has been a chemical change. Student B concludes that there has not been a chemical change, but rather a physical change. Which student's conclusion is valid, based on the information provided?

Answer asap : ( a. how does mucus prevent the entry of pathogens? b. describe two ways white blood cells protect us from pathogens.

You just calculated that the heat of fusion for chloromethane is 6400 j/mol. the heat of fusion for hydrogen is 120 j/mol.? which of the following account for this difference? more than one correcta. chloromethane can absorb more energy at the same temperature. b. hydrogen has stronger intermolecular forces than chloromethane. c. hydrogen molecules can pack more closely than chloromethane molecules. d. chloromethane experiences dipole-dipole interactions. e. chloromethane has a higher molar mass than hydrogen.

What is the magnitude of the force of gravity between to 1000 kg cars which are separated by distance of 25. 0 km on an interstate highway? the force between the two cars will be what