Question
Q1. A student wants to compare the reactivity of an unknown metal, Q with that of zinc Both metals are more reactive than silver. The student is provided with: Silver nitrate solution. Metal Q powder. A thermometer. Normal laboratory equipment. No other chemicals are available. Describe a method the student could use to compare the reactivity of metal Q with that of zinc.Your method should give valid results.
Answer
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Clara
Elite · Tutor for 8 years
Answer
1. Prepare two separate samples of silver nitrate solution, to one sample add the 'Metal Q' powder and to the other sample add zinc powder.2. Observe and record the reactions using the laboratory equipment like a thermometer for the increase in temperature or visual observation for any color changes.3. Reactivity is determined by the metal which causes more observable changes. One can infer that the metal that causes a greater degree of temperature increase or color change is more reactive.
Explanation
In chemistry, to compare the reactivity of two metals, it can be done by observing which metal can displace the other in a solution of its salt. Here, observe whether metal Q can displace zinc from its nitrate or zinc can displace metal Q from its nitrate. Two solution should be prepared, one of zinc nitrate and one of 'Q nitrate'. In each case, observe any changes such as change in temperature (which could be done using the thermometer), or physical changes, such color change which indicates formation of a new product. These changes will give an evidence of a displacement reaction, hence we can determine the reactivity of the two metals.More specifically:Method 1: Take two separate samples of silver nitrate solution. Add zinc powder to the first sample and 'Metal Q' powder to the second. Observe the reaction. Increase in temperature or a color change indicates a chemical reaction and metal displacing silver. The extent of reaction or the speed of the reaction can give an approximate measure of the metal's reactivity. If both Zinc and 'Metal Q' react with Silver Nitrate, the metal with higher reaction rate indicates is more reactive.Method 2: Setup two controlled experiments with silver nitrate solution. In one, add zinc and measure the temperature change using a thermometer on periodic intervals to measure the extent of reaction, where reactivity can be inferred by the amount of heat change.