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A buffer was made by mixing 20cm3 of 0.05M NaOH and 20cm3 of 0.25M propanoic acid. Calculate the pH. Ka=1.34x10^-5

pH is calculated using the equation pH=-log[H+]. The concentration of H+ ions, therefore, needs to be calculated. The amount of each substance can be calculated by multiplying the concentration by the volume...
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Answered by Michael C. • Chemistry tutor
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What is the Oxford Comma?

It's a hot and heavy controversy in the grammar world! Basically, an Oxford comma is a type of serial comma - which is a comma that separates things in a list. The Oxford comma comes specifically before the ...
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Answered by Elizabeth P. • English tutor
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How do you solve the simultaneous equations 3x+y=5 and x-y=3?

The aim of this question is to find x and y by combining these two equations. There are two ways of solving simultaneous equations, elimination and substitution. Elimination can only be used when there are n...
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Answered by Andrew N. • Maths tutor
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How do I decide whether to use the perfect or the imperfect tense?

The perfect and imperfect tenses are both used to describe a past tense in French. The imperfect tense is often a more descriptive tense and is used to set the scene and 'frame' the more punctual perfect ten...
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Answered by Daniel W. • French tutor
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The finite region bounded by the x-axis, the curve with equation y = 2e^2x , the y-axis and the line x = 1 is rotated through one complete revolution about the x-axis to form a uniform solid. Show that the volume of the solid is 2π(e^2 – 1)

The volume of revolution, V, is given as 2π∫ydx Substituting in the equation and limits gives as follows: V = 2π∫2e^2x dx between 0 and 1 Integrating this gives V = 2π[e^2x] between 0 and 1 Applying the limi...
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