Which set of measurements correctly identifies the speed of an object? A.
Distance = 18 m
time = 2 hr
speed = 9m/hr
B.
Distance = 30 km
time = 17 min
speed = 1.8 km/hr
C.
Distance = 3 cm
time = 12 min
speed = 36 cm/min
D.
Distance
2 km
time = 24 sec
speed = 48 km/sec

A. Distance = 18 m

    time = 2 hr

    speed = 9 m/hr

Explanation:

Speed is the same thing as velocity.

Velocity = distance/time

18m/2hr = 9m/hr

For choice B, the numbers are right, but the units are mixed (minutes were changed to hours)

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