Scientific Notation and Significant Figures — Unit test Answers

Mrs. Rushing has 3 chemistry classes with 24 students in each. An experiment calls for each student to use 4 test tubes. How many test tubes are needed in all for her classes?

What is the correct way to write 0.0000250 m in scientific notation?

Consider the substances below.• 1 mol of beryllium• 1 mol of salt• 1 mol of water• 1 mol of hydrogenWhich statement is true about these substances?

Consider the balanced equation below. What is the mole ratio of PCl3 to PCl5?

Which statement best explains the purpose of using a mole in the measurement of matter?

The following balanced equation shows the formation of sulfur dioxide.S + O2 SO2How many moles of sulfur are needed to produce 15.0 mol of sulfur dioxide?

Consider the equation below.Zn + H2SO4 ZnSO4 + H2The mole ratio of zinc to zinc sulfate is

Consider the reaction below.2Al2O3 4Al + 3O2How many moles of oxygen are produced if 11.0 mol of Al are produced?

Which statement best describes the process of making a solution by diluting a stock solution?

What is the relationship between a mole and Avogadro’s number?

Mary performs this calculation.How many significant figures should her answer have?

A 150 mL sample of hydrochloric acid (HCl) completely reacted with 60.0 mL of a 0.100 M NaOH solution. The equation for the reaction is given below.HCl + NaOH NaCl + H2OWhat was the original concentration of the HCl solution?

The molar mass of KCl is 74.55 g/mol. If 8.45 g KCl are dissolved in 0.750 L of solution, what is the molarity of the solution?Use .

Rita divides Avogadro’s number (approximately 6.02214 1023) by 2.055 to calculate the number of atoms in a sample. Which expression gives her result to the correct number of significant figures?

The pictures below show samples of different substances.The mass and volume of each sample differ from the mass and volume of the other samples. Is it possible for each sample to contain 1 mol of each substance?