U3-5-1 - Elemental Microanalysis

Question 1

Empirical formula

Answer 1

The simplest whole number ratio of the elements in a molecule.

(E.g. CH₂ for any alkene)

Question 2

If you are given % by mass of each element in the formula, how do you work out the empirical formula?

1. Treat each % as __________.
2. Divide each mass by the RAM of that element.
3. Divide each number in the ratio by the smallest number in the ratio (to get whole numbers).

Answer 2

If you are given % by mass of each element in the formula, how do you work out the empirical formula?

1. Treat each % as mass in grams.
2. Divide each mass by the RAM of that element.
3. Divide each number in the ratio by the smallest number in the ratio (to get whole numbers).

Question 3

If you are given % by mass of each element in the formula, how do you work out the empirical formula?

1. Treat each % as mass in grams.
2. Divide each mass by ___________.
3. Divide each number in the ratio by the smallest number in the ratio (to get whole numbers).

Answer 3

If you are given % by mass of each element in the formula, how do you work out the empirical formula?

1. Treat each % as mass in grams.
2. Divide each mass by the RAM of that element.
3. Divide each number in the ratio by the smallest number in the ratio (to get whole numbers).

Question 4

If you are given % by mass of each element in the formula, how do you work out the empirical formula?

1. Treat each % as mass in grams.
2. Divide each mass by the RAM of that element.
3. Divide each number in the ratio by the _______________ (to get whole numbers).

Answer 4

If you are given % by mass of each element in the formula, how do you work out the empirical formula?

1. Treat each % as mass in grams.
2. Divide each mass by the RAM of that element.
3. Divide each number in the ratio by the smallest number in the ratio (to get whole numbers).

Question 5

If you are given masses of products, how do you work out the empirical formula?

1. Mass of product _______________ (to work out the mass of each element)
2. Divide each mass by the RAM of that element.
3. Divide each number in the ratio by the smallest number in the ratio (to get whole numbers).

Answer 5

If you are given masses of products, how do you work out the empirical formula?

1. Mass of product × mass of C/H/O etc. ÷ GFM of product (to work out the mass of each element)
2. Divide each mass by the RAM of that element.
3. Divide each number in the ratio by the smallest number in the ratio (to get whole numbers).

Question 6

If you are given masses of products, how do you work out the empirical formula?

1. Mass of product × mass of C/H/O etc. ÷ GFM of product (to work out the mass of each element)
2. Divide each mass by______________.
3. Divide each number in the ratio by the smallest number in the ratio (to get whole numbers).

Answer 6

If you are given masses of products, how do you work out the empirical formula?

1. Mass of product × mass of C/H/O etc. ÷ GFM of product (to work out the mass of each element)
2. Divide each mass by the RAM of that element.
3. Divide each number in the ratio by the smallest number in the ratio (to get whole numbers).

Question 7

If you are given masses of products, how do you work out the empirical formula?

1. Mass of product × mass of C/H/O etc. ÷ GFM of product (to work out the mass of each element)
2. Divide each mass by the RAM of that element.
3. Divide each number in the ratio by____________________ (to get whole numbers).

Answer 7

If you are given masses of products, how do you work out the empirical formula?

1. Mass of product × mass of C/H/O etc. ÷ GFM of product (to work out the mass of each element)
2. Divide each mass by the RAM of that element.
3. Divide each number in the ratio by the smallest number in the ratio (to get whole numbers).

Question 8

If you have the empirical formula and the GFM, how do you find out the molecular formula?

1. Calculate the mass of the __________.
2. Divide GFM by empirical formula mass (to get how many times bigger the real formula is).
3. Multiply empirical formula by this number.

Answer 8

If you have the empirical formula and the GFM, how do you find out the molecular formula?

1. Calculate the mass of the empirical formula.
2. Divide GFM by empirical formula mass (to get how many times bigger the real formula is).
3. Multiply empirical formula by this number.

Question 9

If you have the empirical formula and the GFM, how do you find out the molecular formula?

1. Calculate the mass of the empirical formula.
2. ____________ by empirical formula mass (to get how many times bigger the real formula is).
3. Multiply empirical formula by this number.

Answer 9

If you have the empirical formula and the GFM, how do you find out the molecular formula?

1. Calculate the mass of the empirical formula.
2. Divide GFM by empirical formula mass (to get how many times bigger the real formula is).
3. Multiply empirical formula by this number.

Question 10

If you have the empirical formula and the GFM, how do you find out the molecular formula?

1. Calculate the mass of the empirical formula.
2. Divide GFM by empirical formula mass (to get how many times bigger the real formula is).
3. _________ empirical formula by this number.

Answer 10

If you have the empirical formula and the GFM, how do you find out the molecular formula?

1. Calculate the mass of the empirical formula.
2. Divide GFM by empirical formula mass (to get how many times bigger the real formula is).
3. Multiply empirical formula by this number.