Chemistry Review Sem2

Nitrogen and hydrogen react to produce ammonia as represented by the equation N₂(g) + 3H₂(g) → 2NH₃(g). How many grams of hydrogen are needed to produce 15.0 mol of ammonia if the reaction goes to completion?

• A. 15.0 g

• B. 22.5 g

• C. 45.0 g

• D. 90.0 g

What is the molarity when 2.80 g of Mg(NO₃)₂ are dissolved in enough water to make 75 mL of solution?

• A. 0.25 M

• B. 0.29 M

• C. 0.43 M

• D. 1.8 M

Which of the following is the balanced chemical equation that represents the chemical reaction of potassium and oxygen to produce potassium oxide?

• A. K + O → KO

• B. 4K + O₂ → 2K₂O

• C. K + O₂ → KO₂

• D. 2K + 2O → K₂O₂

The chemical equation represents a reaction between ammonia and oxygen to form nitrogen monoxide and water: 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g). What is the limiting reagent when a 2.00 g sample of ammonia is mixed with 4.00 g of oxygen?

• A. oxygen

• B. ammonia

• C. water

• D. nitrogen monoxide

Tags

NGSS.HS-PS1-7

When magnesium is burned in the presence of oxygen, it produces magnesium oxide according to the following chemical equation: 2Mg + O2 → 2MgO. If 3.45 grams of Mg are burned, how many grams of MgO are produced?

• A. 8.69

• B. 5.72

• C. 4.35

• D. 3.45

Tags

NGSS.HS-PS1-7

The diagram shows a chemical reaction that occurs between hydrogen and oxygen. Which scientific law is best demonstrated by the reaction shown in the diagram?

• law of angular momentum

• law of universal gravitation

• law of conservation of mass

• law of conservation of energy

Tags

NGSS.HS-PS1-7

What is the molarity of a solution when 2.75 g of NaCl is dissolved in 1100 mL of solution?

• 0.043 M

• 0.25 M

• 0.43 M

• 4.27 M

If the actual yield of a compound is 0.198g and the theoretical yield is 0.217g, find the percent yield.

• A. 10.9%

• B. 22%

• C. 8.7%

• D. 91.2%

After being underwater for long periods of time, divers will have more nitrogen and oxygen dissolved in their blood and need to rise slowly to the surface to allow these gases to come out of solution. Which of these explains why the concentration of these gases increases while the divers are underwater?

• Decreased pressure increases the solubility of these gases.

• Increased pressure increases the solubility of these gases.

• Decreased pressure decreases the solubility of these gases.

• Increased pressure decreases the solubility of these gases.

A solution was created by mixing an unknown powdery compound with distilled water. A conductivity test on the solution determined that the solution formed was a good conductor of electricity. Which statement is a valid conclusion based on this information?

• The solution is a base.

• The solution is an acid.

• The powdery substance is an ionic compound.

• The powdery substance is a covalent compound.