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An amino acid contains 52.2% carbon, 9.3% hydrogen, 8.7% nitrogen and 29.8% oxygen by mass and has a relative molecular mass of 161 g/mol. What is its molecular formula? What functional groups must it have?

In 100g of compound, the amount of each element is given by: C: n = 52.2/12 = 4.35 H: n = 9.3/1 = 9.3 N: n = 8.7/14 = 0.621... O: n = 29.8/16 = 1.8625 Dividing through by the smallest amount (0.621) gives...

Answered by Georgina B. • Chemistry tutor

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A ball of mass 500g is dropped from rest 2m above the ground. When it reaches the ground it is travelling at 5m/s. How much energy has been dissipated?

Initial energy (Gravitational Potential): E = mgh = 0.5 x 9.81 x 2 = 9.81J Final energy (Kinetic): E = mv²/2 = (0.5 x 5²)/2 = 6.25J Energy lost = 9.81 - 6.25 = 3.56J

Answered by Georgina B. • Physics tutor

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Prove that the square of an odd number is always 1 more than a multiple of 4

(2x-1)² = 4x²- 4x + 1= 4(x²-x)+1The part of the expression which is: 4(x²-x) indicates that the value is a multiple of 4. The number 1 is then added which means...

Answered by Gokul P. • Maths tutor

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4y^2 = 256, Find a value for y

y^2 = 256/4 = 64
therefore, y = sqrt(64) = 8

Answered by Kai P. • Maths tutor

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A circle with centre C has equation x^2+8x+y^2-12y=12. The points P and Q lie on the circle. The origin is the midpoint of the chord PQ. Show that PQ has length nsqrt(3) , where n is an integer.

First complete the square for both x and y. Move all constants to the right hand side. The square root of this is the radius of the circle. The two constants in the completed square bracket show the x and...

Answered by • Maths tutor

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