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A sample of CaCO3 has been weighed in at 6.3 g. How many moles of calcium carbonate are present?

The first thing to think of here is what does a mole actually mean?Using the equation: Moles = Mass (g) / Molar Mass we can first find out what the molar mass of CaCO 3 is.TO THE PERIODIC TABLE!1) List the i...
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Answered by Thomas C. • Chemistry tutor
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If y=5x+4x^3, find dy/dx.

When asked to find dy/dx, this means to differentiate. Differentiation is also a method of calculating the gradient of a line. (dy/dx = gradient.) The rule of differentiation is as follows: Step 1 : Differen...
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Answered by Umair H. • Maths tutor
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How would you solve the simultaneous equations 2x + y = 7 and 3x - y = 8

To solve a pair of simultaneous equations you need to find the values of x and y which are the same for both equations. To do this you should eliminate one of the unknowns - in this instance it can easily be...
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Answered by Kenna H. • Maths tutor
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If an equation of a line is y=2x+4 and it crosses the x axis at point R, what is the value of x?

Since we know that the line crosses the x axis, we can assume that the value of Y at this point is 0. So we must substitute y = 0 into the equation y = 2x + 40 = 2x + 4we now have to isolate x on its own so ...
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Answered by Abigail C. • Maths tutor
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Josie walks into her house from outside, as she enters a dark room, a spider falls in front of her face, describe the changes that occur in the eye to visualise a close up object in the dark.

This question aims to address the following learning objective:To be able to relate the structures of the eye to their functions. This includes: accommodation to focus on near or distant objects and adaptati...
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Answered by Michaela G. • Biology tutor
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