Answer:
<em>a)</em> <em>1.392 x 10^6 g/cm^3</em>
<em>b) 8.69 x 10^7 lb/ft^3</em>
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Explanation:
mass of the star m = 2.0 x 10^36 kg
radius of the star (assumed to be spherical) r = 7.0 x 10^5 km = 7.0 x 10^8 m
The density of substance ρ = mass/volume
The volume of the star = volume of a sphere = 
==> V =
= 1.437 x 10^27 m^3
density of the star ρ = (2.0 x 10^36)/(1.437 x 10^27) = 1.392 x 10^9 kg/m^3
in g/cm^3 = (1.392 x 10^9)/1000 = <em>1.392 x 10^6 g/cm^3</em>
in lb/ft^3 = (1.392 x 10^9)/16.018 = <em>8.69 x 10^7 lb/ft^3</em>
Answer: 631.8 g
Explanation:

It can be seen from the balanced chemical equation, 2 moles of ethane reacts with 7 moles of Oxygen gas to produce 4 moles of carbon dioxide and 6 moles of water.
Ethane is the limiting reagent as it limits the formation of product.
Thus, if 2 moles of ethane produce 6 moles of water.
11.7 moles moles of ethane produce=
of water.
Mass of water= no of moles
Molar mass
Mass of water= 35.1
18g/mol= 631.8 g
I believe it is Sodium. I could be wrong though.
Answer:
a
Explanation
Bc I took the test, good luck with that guys