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CaCO3 + 2HCl = ?

CaCO 3 is a carbonate and HCl is an acid, so the products will be a salt, water and Carbon Dioxide.Removing 2 Hydrogen atoms and an Oxygen atom for the H 2 O, and one carbon atom and 2 Oxygen atoms for the C...
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Answered by Toby G. • Science tutor
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Given the mass number of Aluminium is 27 and the mass number of Oxygen is 16, how many moles of Al2O3 are in 30g? (3 significant figures)

Molar Mass of Al 2 O 3 = 27+27+16+16+16 = 102Mass = mol*Mr so mol = Mass/Mrmol = 30/102 = 0.294117... = 0.294 moles
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Answered by Toby G. • Chemistry tutor
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Given I climb two steps every second and I have a mass of 50kg, what is the power output of my legs in kilowatts? (3 significant figures)

(There is a diagram showing stairs with steps that are 20cm high) Power = Energy/TimeEnergy required to climb one step = Work Done = Force DistanceForce = Weight = m g = 50 9.81 = 490.5NEnergy = 490.5 0.2 = ...
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Answered by Toby G. • Physics tutor
2604 Views

Given the area of the pool is 63m^2, what is the value of x?

(There is a diagram showing a rectangle with one side labelled x+4 and another labelled x+6)Area = (x+4)(x+6)63m^2 = x 2 +10x+240 = x 2 +10x-390 = (x-3)(x+13) x-3=0 so x=3x+13=0 gives x=-13, which cannot be ...
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Answered by Toby G. • Maths tutor
3454 Views

What is the best way to plan a letter for a writing exam in Japanese?

Start with the name and addressThe traditional greetings and pleasantriesRespond to anything mentioned in the question. For example did they mention something about their family or ask you a question?In the ...
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Answered by Victoria L. • Japanese tutor
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