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As the volume of blood in the ventricles of the heart increases, with all other factors constant, stroke volume increases till a point. Explain why. (5)

Define stroke volume as the volume of blood expelled by the left ventricle into the aorta per contraction of the heart.Idea that as blood volume in the ventricle increases, this stretches the sarcomeres o...

Answered by Azmaeen Z. • Biology tutor

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How can natural selection create two different species from one species?

For speciation to occur, two populations of a species must become reproductively isolated. This can result from either the formation of a geographic barrier between two populations of the species, prevent...

Answered by Sean K. • Biology tutor

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The Haber process is used to produce ammonia. (Insert equation here) Explain the optimum conditions for this reaction and why these may differ from the conditions used in industry.

N₂ (g)+3H₂ (g) ⇋ 2NH₃ (g) ΔH=-92kJmol^-1 (this is the equation for the above question)
According to Le Chatelier's principle, the position of equilibrium w...

Answered by • Chemistry tutor

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Calculate the pH of a 0.0131 mol dm^-3 solution of calcium hydroxide at 10 degrees centigrade.

Multiply by 2 because calcium hydroxide = Ca(OH)2 so 2 x [OH-] per molecule.[OH-] = 0.0131 x 2 = 0.0262
Insert [OH-] value into the equilibrium equation along with the value of Kw at 10 degrees centi...

Answered by Emily W. • Chemistry tutor

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Explain why adding small amounts of acid or base hardly changes the pH of an acidic buffer solution.

An acidic buffer solution is made up of a weak acid (e.g. ethanoic acid) and a salt containing its conjugate base (e.g. sodium ethanoate). It resists pH change via two mechanisms: The fact that the acid i...

Answered by • Chemistry tutor

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