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When 80.0cm^3 of 0.500 M hydrochloric acid was added to 1.75g of impure CaCO3, not all HCl reacts. The unreacted HCl required 22.4 cm^3 of a 0.500 M solution of NaOH for complete reaction. Calculate percentage by mass of CaCO3 in the impure sample.

Balanced equations: CaCO 3 + 2 HCl --> CaCl 2 + H 2 O + CO 2 , HCl + NaOH --> NaCl + H 2 O HCl moles that react overall: (80.0 cm 3 x 0.500 mol dm 3 ) / 1000 dm 3 cm -3 = 4.00 x 10 -2 mol HCl moles tha...
Answered by • Chemistry tutor
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During your holidays in Spain you write a blog to describe your experiences. Mention: a day when you had problems and a festival you would like to go to.

I would help the student with this question by breaking down the core things examiners are looking for- which is: creative and complex use of language, expressing and justifying opinions and using appropriat...
EW
Answered by Ellie W. • Spanish tutor
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How do covalent bonds work?

Firstly, let's define a covalent bond as being a shared pair of electrons, between two positively charged nuclei, with one being donated from each ion/atom. Let's note that an electron has a negative charge,...
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Answered by Jack W. • Chemistry tutor
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What is the difference in the evaluation of a study versus a theory?

When evaluating studies, you are assessing how useful the findings of the studies are in explaining the key question within the topic. Therefore, all evaluation points need to refer to the strengths and limi...
JO
Answered by Junior O. • Psychology tutor
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Daniel and Mohammed buy concert tickets for £63. All the concert tickets are the same price. Daniel pays £24.50 for 7 tickets. How many tickets does Mohammed buy? .

24.5 Divided by 7 = 3.5.63-24.5= 38.538.5 Divided by 3.5 = 11
DH
Answered by Danny H. • Maths tutor
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