Use exponential notation to express 4.22 mg in grams

A 0.231 g piece of solid magnesium reacts with gaseous oxygen from the atmosphere to form solid magnesium oxide.  In the laboratory a student weighs the mass of the magnesium oxide collected from this reaction as 0.309 g.

Aqueous hydrochloric acid  HCl  will react with solid sodium hydroxide  NaOH  to produce aqueous sodium chloride  NaCl  and liquid water  H2O . Suppose 28. g of hydrochloric acid is mixed with 53.0 g of sodium hydroxide. Calculate the minimum mass of hydrochloric acid that could be left over by the chemical reaction. Be sure your answer has the correct number of significant digits.

A bar of gold measures 0.127 m x 0.0483 m x 0.0155 m. How many gallons of water have the same mass as this bar? Number Units

Saline solution is a sodium chloride solution that is 0.90% mass/volume. How many grams of sodium chloride are needed to make 135 mL of saline solution?

A student is asked to make up a 16% sodium chloride solution. She makes the solution by weighing an empty beaker (which has a mass of 98.5g). Sodium chloride is added to the beaker. The mass of the beaker and sodium chloride is 114.71 g. Lastly, the student added 84 mL of distilled water to the beaker. Reweighing the beaker she finds that the mass of the beaker, sodium chloride, ad distilled water is 196.14 g. What is the weight percentage of sodium chloride in this solution? Show all work.

A 0.271 g piece of solid magnesium reacts with gaseous oxygen from the atmosphere to form solid magnesium oxide. In the laboratory a student weighs the mass of the magnesium oxide collected from this reaction as 0.259 g.