Photo AI

5 (a) An atom of aluminium has an atomic mass of 27 - Edexcel - GCSE Chemistry - Question 5 - 2022 - Paper 1

Question icon

Question 5

5-(a)-An-atom-of-aluminium-has-an-atomic-mass-of-27-Edexcel-GCSE Chemistry-Question 5-2022-Paper 1.png

5 (a) An atom of aluminium has an atomic mass of 27. Aluminium has an atomic number of 13. State the number of electrons, neutrons and protons in this atom. number ... show full transcript

Worked Solution & Example Answer:5 (a) An atom of aluminium has an atomic mass of 27 - Edexcel - GCSE Chemistry - Question 5 - 2022 - Paper 1

Step 1

State the number of electrons, neutrons and protons in this atom.

96%

114 rated

Answer

The number of electrons in an atom is equal to its atomic number. For aluminium, the atomic number is 13, so:

  • number of electrons = 13

To find the number of neutrons, we subtract the atomic number from the atomic mass:

  • number of neutrons = atomic mass - atomic number = 27 - 13 = 14

The number of protons is the same as the atomic number:

  • number of protons = 13

Step 2

Calculate the empirical formula of this sample of aluminium bromide.

99%

104 rated

Answer

First, we calculate the number of moles of aluminium and bromine:

  1. Moles of aluminium: Moles of Al=massmolar mass=1.35g27.0g/mol=0.05 mol\text{Moles of Al} = \frac{\text{mass}}{\text{molar mass}} = \frac{1.35g}{27.0g/mol} = 0.05 \text{ mol}

  2. Moles of bromine: Moles of Br=12.00g80.0g/mol=0.15 mol\text{Moles of Br} = \frac{12.00g}{80.0g/mol} = 0.15 \text{ mol}

Now, we find the simplest whole number ratio:

  • To find the ratio, we divide both by the smallest number of moles: Ratio of Al=0.050.05=1\text{Ratio of Al} = \frac{0.05}{0.05} = 1 Ratio of Br=0.150.05=3\text{Ratio of Br} = \frac{0.15}{0.05} = 3

Thus, the empirical formula is:

  • AlBr₃

Join the GCSE students using SimpleStudy...

97% of Students

Report Improved Results

98% of Students

Recommend to friends

100,000+

Students Supported

1 Million+

Questions answered

;