A technician uses a magnesium ribbon in a reaction with dilute acid. Fig. 1 shows the metallic structure before the reaction. The ribbon is polished first t...
Question 1 Report
A technician uses a magnesium ribbon in a reaction with dilute acid. Fig. 1 shows the metallic structure before the reaction. The ribbon is polished first to remove surface oxide. It reacts to form a magnesium solution and hydrogen gas. The technician also notes that magnesium can be bent carefully without breaking.
(a) Name the gas made when magnesium reacts with acid. [1]
(b) Give one test for this gas. [1]
(c) Suggest why magnesium ribbon is malleable. [2]
(d) Complete the word equation: magnesium + acid → magnesium salt + ______. [1]
The diagram shows a conductivity test carried out by a student. Two graphite rods are connected to a battery and placed in molten lead bromide. A lamp lights after the solid has been heated above its melting point. The student repeats the test with solid lead bromide, using the same voltage.
(a) Name the type of bonding in lead bromide. [1]
(b) What happens to the lamp when solid lead bromide is tested? [1]
(c) Use the particle model to suggest why molten lead bromide conducts. [2]
(d) Give the name of the negatively charged ion in lead bromide. [1]
Answer Details
Magnesium and acid
- (a) The gas made is hydrogen. [1]
- (b) A lit splint gives a squeaky pop with hydrogen. [1]
- (c) Magnesium is malleable because layers of metal ions can slide past each other. Metallic bonding remains because the delocalised electrons still attract the positive ions. [2]
- (d) magnesium + acid → magnesium salt + hydrogen. [1]
Molten lead bromide
- (a) Lead bromide has ionic bonding. [1]
- (b) With solid lead bromide, the lamp stays off because the ions cannot move. [1]
- (c) When molten, ions are free to move. These moving ions carry electrical charge, so molten lead bromide conducts. [2]
- (d) The negatively charged ion is the bromide ion. [1]
Download The App On Google Playstore
Everything you need to excel in your exams
