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The mass of a balloon is 0.02g before it is filled with air. After it is blown up with air the mass is 0.04g. Assuming oxygen makes up 21% of air, calculate the number of moles of oxygen in the balloon.

After the balloon has been blown up with air it increased its size by 0.02 g (Final mass - initial mass = mass of the air).We are told that of oxygen takes up 21% of air. Therefore, we need to work out 21% o...
GS
Answered by Greta S. • Chemistry tutor
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How does osmoregulation occur in the kidney?

The tubule fluid enters the collecting duct (CD) where the final water reabsorption occurs before the fluid is excreted as urine. Osmoreceptors in the hypothalamus detect the concentration of the blood (wate...
KD
Answered by Kelly D. • Biology tutor
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How do you factorise a quadratic equation where the coefficient of x^2 isn't 1?

For this, we need to use the formula ax 2 +bx+c. Multiply the coefficient of a from your equation with the value of c. This gives you a value from which you need to find 2 factors of this value which also ad...
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Answered by Rosie G. • Maths tutor
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What is the problem of evil?

According to many passages in the Bible, God is said to be omnibenevolent (all-loving), omnipotent (all-powerful) and omniscient (all-knowing). Evidence of evil in our world is abundant, with moral evil taki...
KS
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To what extent did the Boer war strengthen Britain’s position, 1899-1914?

The Boer war (1899-1902) was an armed conflict fought between the forces of the British empire and the independent Boer states of the Transvaal and Orange free state. Though initially it took on the characte...
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Answered by Samuel P. • History tutor
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