Number of moles = mass of product / molecular mass
=mass of product (MgO) / 40.3
Since the mass of MgO is not given in the question, the correct answer choice cannot be given. However, proceeding witht eh above formula will enable you to find the correct number of moles given the mass of MgO.
I believe the answer is B. a million or more.
Qualitative observation. Which is data or information with your senses such as sight, taste, smell, and touch.
Answer:
a) 250 N
b) 50 N
c) 5000 J
d) 4
e) 3.33
Explanation:
Given that weight of piano (
) = 1000 N, distance moved by pulley (
) = 5 m and the rope used (
) =20 m
a) The effort applied (
) if it was an ideal machine is:
b) If the actual effort = 300 N
The force to overcome friction = actual effort - = 300 - 250 = 50 N
c) Work output = 
d) ideal mechanical advantage (IMA) = 
e) Input force = 300 N, Therefore:
actual mechanical advantage = / input force = 1000 / 300 = 3.33
