I hope this is right because i just took a chemistry mock exam
The element symbol on the periodic table indicate the states of matter
Answer: Number of energy shells
Explanation:
Periods = no. of shells
Groups = no. of electrons in outer shells
Answer:
Chemical properties can change due to a variety of things. If you were to talk about Weathering, the chemical properties change when there is acid rain, water, CO2, and O2. Chemical Properties change when the chemical properties of an object change too.
Answer:
B
Explanation:
If the temperature of the water goes up, the reaction is exothermic (heat is being given away by the equation -- more precisely the reactants of the equation). Only A and B can be true. In order for the reaction to occur, the water has to absorb the heat. It's temperature goes up. Remember that minus sign. It is almost the key fact for this question.
The question is not as hard as it looks, but that is easy for me to say.
m = 100 g
c = 4.2 J/(g * oC)
deltaT = 21 - 20 degrees = 1 degree.
Heat = 100 * 4.2 * 1
Heat = 420 J
Heat = 420 * [1 kJ/1000 J]
Heat = -0.42 kJ
B
