Experiments were done on a certain pure substance [tex]$X$[/tex] to determine some of its properties. There's a description of each experiment. In each case, decide whether the property measured was a chemical or physical property of [tex]$X$[/tex], if you can. If you don't have enough information, choose 'can't decide' in the third column.
| property | experiment | physical or chemical? |
|---|---|---|
| D | A sample of [tex]$X$[/tex] is carefully weighed and put inside a vented flask. Water is added to the flask until it just covers the sample, and the volume of sample and water is recorded. Then the sample is removed and the volume of water alone recorded. From the mass of the sample and the difference in volumes, the value of [tex]$D$[/tex] may be calculated. | physical chemical (can't decide) |
| 0 | A sample of solid [tex]$X$[/tex] is carefully weighed and put inside a vented flask. The flask is heated until oxygen gas starts being produced. After no more oxygen gas is produced, the contents of the flask are removed and weighed, and from the decrease in weight the value of [tex]$O$[/tex] may be calculated. | physical chemical (can't decide) |
| C | A sample of [tex]$X$[/tex] is carefully weighed and put inside a sealed calorimeter. Pure oxygen gas is injected into the calorimeter, and the mixture ignited. After all of [tex]$X$[/tex] has reacted with the oxygen gas, the temperature rise of the calorimeter is measured. From this change in temperature the value of [tex]$C$[/tex] may be calculated. | physical chemical (can't decide) |
Answer (1)
Property D involves measuring density without changing the substance's composition, so it's a physical property.
Property O involves heating the substance to produce oxygen gas, indicating a chemical change.
Property C involves reacting the substance with oxygen in a calorimeter, also indicating a chemical change.
Therefore, D is physical, and O and C are chemical.
Explanation
Understanding the Problem We need to determine whether the properties D, O, and C are physical or chemical properties of substance X based on the descriptions of the experiments.
Analyzing Property D For property D, the experiment involves weighing a sample of X, adding it to water, and measuring the volume change. The density is calculated from the mass and volume. This process does not change the chemical composition of substance X. Therefore, it is a physical property.
Analyzing Property O For property O, the experiment involves heating a sample of X until oxygen gas is produced. This indicates that substance X is decomposing or reacting to form oxygen. This process changes the chemical composition of substance X. Therefore, it is a chemical property.
Analyzing Property C For property C, the experiment involves igniting a sample of X in a calorimeter with oxygen gas. This means X reacts with oxygen, and the temperature rise is measured. This process changes the chemical composition of substance X. Therefore, it is a chemical property.
Final Answer In summary:
Property D is a physical property.
Property O is a chemical property.
Property C is a chemical property.
Examples
Understanding the difference between physical and chemical properties is crucial in many real-world applications. For example, in cooking, physical changes occur when you mix ingredients or boil water, but chemical changes happen when you bake a cake, as the ingredients react to form new compounds. In environmental science, knowing whether a pollutant undergoes a physical change (like dilution) or a chemical change (like degradation) helps in predicting its impact and designing remediation strategies. Similarly, in material science, understanding these properties helps in selecting the right materials for specific applications, such as choosing a metal that resists chemical corrosion for building bridges.
