Consider the balanced chemical reaction, 4 NH3(g) + 5 O2(g) \longrightarrow 4 NO(g) + 6 H2O(g)

if the rate of change of NH3 (∆[NH3]/∆t) is −2.6 x 10−3 M/s at a particular time, what is rate of the reaction at the same time?

a. 1.04x10−3 M/s

b. 6.5×10−4 M/s

c. −6.5×10−4 M/s

d. −1.04×10−3 M/s

e. 2.6 x 10−3 M/s

What rule is used to determine how many covalent bonds an element can form? a. the number of covalent bonds is equal to six c the number of covalent bonds is equal to five minus the group number plus the group number b. the number of covalent bonds is equal to eight d. none of the above minus the group number select the best answer from the choices provided