The table shows the thermodynamic data for a reaction.

thermodynamic data
energy of the reactants energy of the products activation energy
−420 kj −240 kj −310 kj

which of the following statements explains if the reaction is endothermic or exothermic?
the change in enthalpy is +180 kj, so it is an endothermic reaction.
the change in enthalpy is −180 kj, so it is an exothermic reaction.
the activation energy is lower than the change in enthalpy, so it is an exothermic reaction.
the activation energy is higher than the change in enthalpy, so it is an endothermic reaction.

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.

i just calculated it all out, and not including weekends, and all the different days off. as of this school year (2018-2019) students are spending 2198 hours in school this year

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o