Final answer:
To find the final mass of a combined sample, add the individual masses using a calculator and round off the result to the same number of decimal places as the least precise measurement. This method respects significant figures and the law of conservation of mass.
Step-by-step explanation:
To find the final mass of a combined sample in chemistry, follow these steps:
- Use a calculator to add the individual masses together.
- Report the sum to the same number of decimal places as the measurement with the least number of decimal places to ensure significant figures are accurately represented.
- For example, combining 16.7 g and 5.24 g, we calculate the sum as 21.94 g. Due to significant figure rules, the correct final mass should be rounded to 21.9 g.
Significant figures are vital to maintain the precision of your measurements. If you add two masses and one mass is known to fewer decimal places, the final result should be rounded to match that limitation. The use of significant figures reflects the certainty of each measurement.
In chemical equations, the law of conservation of mass suggests the combined mass of reactants and products in a chemical reaction should remain constant. Calculating the final mass of a sample involves finding the mass of individual elements or compounds, adding them together, and applying the principles of significant figures. In some instances, you may need to determine the number of moles and use the atomic masses of elements to find the masses of various components of a sample.