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
Answer:
the empirical (lowest raios) is
C2H4Cl
Explanation:
A compound is known to consist solely of carbon, hydrogen, and chlorine. Through elemental analysis, it was determined that the compound is composed of 24.27% carbon.
What is the empirical formula of this compound?
the compound has ONLY C, H, and Cl
the % Cl = 100% - 24.27% -4.03% = 71.7%
in 100 gm, there are 71.7 gm Cl, 24.27 gm C, and 4.03 gm H
the number of moles are Cl=71.7/70.91 =1.01= ~ 1
C = 24.27/12.0 = 2.02 =~ 2
H = 403/1.01 = 3.97 =~ 4
so the empirical (lowest raios) is
C2H4Cl
Answer:
A. The total mass of the reactants in a reaction equals the total mass of the product(s).
Explanation:
The law of conversation of matter tells us that in a chemical reaction, matter is never created or destroyed, it's simply converted from one form to another. So the mass of reactants should always equal the mass of the products in a chemical reaction.
Tell the teacher, do NOT clean it up yourself.
