The table shows some common ions. Negative ions Nitrate NO3− Oxide O2− Positive ions Aluminium A3+ Magnesium Mg2+ (a) Write the formula for aluminium oxide. (b) A teacher wrote the formula for magnesium nitrate as: MgNO3 A student says that the formula is incorrect. Who is right? Explain your answer. (c) Aluminium sulfide reacts with dilute hydrochloric acid. (i) Balance the equation for this reaction. Al2S3 + HCl → AlCl3 + H2S (ii) The table shows the melting point and boiling point of H2S. Melting point -85.5°C Boiling point -60.7°C What state does H2S exist in at room temperature?

Photo AI

The table shows some common ions - OCR Gateway - GCSE Chemistry: Combined Science - Question 19 - 2018 - Paper 1

Question 19

The table shows some common ions. Negative ions Nitrate NO3− Oxide O2− Positive ions Aluminium A3+ Magnesium Mg2+ (a) Write the formula for aluminium oxide. ... show full transcript

Worked Solution & Example Answer:The table shows some common ions - OCR Gateway - GCSE Chemistry: Combined Science - Question 19 - 2018 - Paper 1

Step 1

Write the formula for aluminium oxide.

96%

114 rated

Answer

The formula for aluminium oxide is given by the combination of aluminium and oxide ions. Since aluminium has a charge of +3 and oxide has a charge of -2, we need to balance the charges to create a neutral compound. The formula is therefore represented as:

$ext{Al}_2 ext{O}_3$

Step 2

A teacher wrote the formula for magnesium nitrate as: MgNO3 A student says that the formula is incorrect. Who is right? Explain your answer.

99%

104 rated

Answer

The teacher is incorrect in stating that MgNO3 is the correct formula for magnesium nitrate. The correct formula should be Mg(NO3)2. Magnesium has a charge of +2 while the nitrate ion has a charge of -1. For the compound to be neutral, we need two nitrate ions to balance the +2 charge of magnesium. Thus, the correct formula is:

$ext{Mg(NO}_3 ext{)}_2$

Step 3

Balance the equation for this reaction.

96%

101 rated

Answer

The balanced chemical equation for the reaction of aluminium sulfide with hydrochloric acid is:

ightarrow 2 ext{AlCl}_3 + 3 ext{H}_2 ext{S}$$

Step 4

What state does H2S exist in at room temperature?

98%

120 rated

Answer

At room temperature, H2S exists as a gas. This conclusion is based on the provided melting point of -85.5°C and boiling point of -60.7°C, which indicates that H2S will be in the gaseous state at standard room temperature (around 20-25°C).

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