For which of the following activities might you want to hire a chemist?
Answer: D. testing a rock sample for gold content
Which of the following procedures involves a physical change in one of the substances?
Answer: C. separating a salt solution by evaporating the water
15.3 litres of water will be produced if we take 1.7 litres of Hydrogen
Explanation:
Let's take a look over synthesis reaction;
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<u>Balancing the chemical reaction;</u>
<u> </u>
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Thus, 2 moles of hydrogen molecules are required to form 2 moles of water molecules.
<u>Equating the molarity;</u>
<u />
= 
(Since, the molecular mass of hyd and water is 2 and 18 respectively)
x=
x= 15.3 litres.
Thus,15.3 L of water will be produced if we take 1.7 litres of Hydrogen in a synthesis reaction.
Chlorine will have the slowest rate of diffusion because it has the highest relative molecular mass of 71 followed by O₂ with 32, then Neon 20 then He with 2
The rate of diffusion of a gas is inversely proportional to the square root of its relative molecular mass.
Answer:
Phase C - Liquid State
Phase E - Gaseous State
Explanation:
Usually, in phases of water, we have the following;
When temperature is less than zero, it is said to be in its solid phase as ice.
When temperature is between 0 to 100, we can say it is in the liquid phase as water.
When temperature is above 100°C, It is said to be in the gaseous phase as vapour.
From the diagram;
Phase C is the only liquid state because it falls between temperature of 0°C and 100°
Also, only phase E is in the gaseous phase because the temperature is above 100°C.
