Quiz 3 - Chemistry and the Scientific Method | Chemistry and the Scientific Method
General Chemistry 1 - Quiz 3 - Chemistry and the Scientific Method
Which statement best represents a principle of the scientific method?
The scientific method relies on empirical evidence gathered through observation and experimentation. Hypotheses are formulated and then tested through experiments. Based on the evidence gathered, the hypotheses are then either accepted or rejected. This process is iterative and does not treat theories as unquestionable facts.
Which property of matter is intensive?
Density is an intensive property that does not change with the amount of substance present. It is characteristic of the material itself, while mass, volume, and weight are extensive properties that depend on the amount of matter.
Which change of state is correctly paired with its process?
Sublimation is the process where a solid changes directly into a gas without passing through the liquid state. Deposition is the process where a gas changes into a solid without becoming a liquid first. Vaporization is the transition from liquid to gas, and condensation is the transition from gas to liquid.
Which unit is not a base unit in the International System of Units (SI)?
The calorie is not a base unit in the International System of Units (SI); it is a unit of energy. The base unit for energy in SI is the joule. The other options, Kelvin, kilogram, and ampere, are all base units for temperature, mass, and electric current, respectively.
Which of the following best illustrates the use of significant figures in scientific measurement?
Significant figures indicate the precision of scientific measurements. Reporting the length of a rod as 2.0 meters reflects a precision to the tenth of a meter and implies the measurement has been taken seriously to that level of detail. The other options either do not show an understanding of precision or imply incorrect levels of certainty.
What is the best practice for reporting the uncertainty of a measured physical quantity?
Uncertainty is an inherent part of every measurement, and the best practice to report it is as a range derived from multiple measurements. This gives an estimate of the precision of the measurements and the likely error bounds. Overestimating the error or using too many significant figures can be misleading, and ignoring variances disregards the principle of uncertainty.
When combing measurements with different degrees of uncertainty, how should the final result be reported?
When calculations involve several measurements, the final result should be reported with the same number of significant figures as the least precise measurement. This reflects the actual precision of the combined data and ensures that the reported uncertainty is consistent with the input measurements.
In dimensional analysis, what is the purpose of conversion factors?
Conversion factors are used in dimensional analysis to convert between units within the same system or between different systems of measurement. They ensure that the magnitude of the quantity remains the same despite the change in units. They are not used to manipulate numerical values arbitrarily, reduce quantities to dimensionless numbers, or correct errors.
Which of the following is an example of a chemical property?
The ability to corrode is a chemical property that describes a substance's tendency to undergo oxidation or degradation when exposed to certain environmental conditions. Unlike physical properties such as color, melting point, and conductivity, which can be observed without changing the substance's chemical composition, corrosion involves a chemical reaction leading to the formation of new compounds.
Which of the following statements best describes physical properties?
Physical properties are characteristics of a substance that can be observed or measured without altering its chemical composition. These properties include traits such as color, density, melting point, and conductivity, among others. Unlike chemical properties, physical properties do not involve the transformation of one substance into another through a chemical reaction.