Questions from General Chemistry

Q: What were the four fundamental substances postulated by the Greeks?

What were the four fundamental substances postulated by the Greeks?

Q: When a large or small number is written in standard scientific notation

When a large or small number is written in standard scientific notation, the number is expressed as the product of a number between 1 and 10, multiplied by the appropriate power of 10. For each of the...

Q: Classify the following as mixtures or pure substances. a.

Classify the following as mixtures or pure substances. a. a multivitamin tablet b. the blue liquid in your car’s windshield reservoir c. a ham and cheese omelet d. a diamond

Q: Classify the following mixtures as heterogeneous or homogeneous. a.

Classify the following mixtures as heterogeneous or homogeneous. a. soil b. mayonnaise c. Italian salad dressing d. the wood from which the desk you are studying on is made e. sand at the beach

Q: Why can the length of the pin shown in Fig. 2

Why can the length of the pin shown in Fig. 2.5 not be recorded as 2.850 cm?

Q: Indicate the number of significant figures in each of the following:

Indicate the number of significant figures in each of the following: a. 250. b. 250 c. 2.5 * 102 d. 250.0

Q: Indicate the number of significant figures implied in each of the following

Indicate the number of significant figures implied in each of the following statements: a. The population of the United States in 2016 was 324 million. b. One minute is equivalent to 60 seconds. c....

Q: When we round off a number, if the number to the

When we round off a number, if the number to the right of the digit to be rounded is greater than 5, then we should

Q: In a multiple-step calculation, is it better to round

In a multiple-step calculation, is it better to round off the numbers to the correct number of significant figures in each step of the calculation or to round off only the final answer? Explain.

Q: Round off each of the following numbers to three significant digits,

Round off each of the following numbers to three significant digits, and express the result in standard scientific notation. a. 254,931 b. 0.00025615 c. 47.85 * 103 d. 0.08214 * 105