Answer:
Part A: 
to two significant figures
Part B: 
to two significant figures
Part C: 
to two significant figures
Explanation:
Given that :
mass of the hydrogen = 0.30 g
the molar mass of hydrogen gas molecule = 2 g/mol
we all know that:
number of moles = mass/molar mass
number of moles = 0.30 g /2 g/mol
number of moles = 0.15 mol
For low temperature between the range of 50 K to 100 K, the specific heat at constant volume for a diatomic gas molecule = 
For Part A:
to two significant figures
Part B. For hot temperature, 
to two significant figures
Part C. For an extremely hot temperature, 
to two significant figures
Answer:
91.3 kg
Explanation:
weight = m*g
m: mass
g: gravity = 9.8 or 10 (depends on what your instructor tells you to use)
mass = w/g
895/9.8 = 91.3 KG
TheThe relative velocity of Deigo will be 27km/h .
<h3>What is relative Velocity? </h3>
The relative velocity is the velocity of an object with respect to another observer. It is the time rate of relative position of one object with respect to another object .
Vab = Va-Vb
Where a is object and b is observer .
We have given here the velocity of ball 20km/ h
and the another velocity is 7km/ h
Let us assume that Diego is also moving in the direction where ball is moving so the relative velocity will be
V = 20+7=27km/ h
When both observer and object is moving in same direction than there sum of velocity will be relative velocity ,if they are moving opposite than subtraction.
to learn more about Relative velocity click Here brainly.com/question/6070547
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