Chemical Reactions and Stoichiometry Mastery Quiz

Which of the following best represents the law of conservation of matter in a chemical reaction?

• The total mass of reactants is always greater than the products
• The number of atoms of each element remains the same before and after the reaction
• The volume of reactants always equals the volume of products
• The number of molecules in reactants always equals the number in products

Tags

NGSS.MS-PS1-5

In the chemical equation 2H₂ + O₂ → 2H₂O, what does the coefficient '2' before H₂O represent?

• The number of hydrogen atoms in water
• The number of oxygen atoms in water
• The number of moles of water produced
• The atomic mass of water

Tags

NGSS.MS-PS1-5

Which of the following is a correct representation of the following chemical reaction 'sodium reacts with chlorine to form sodium chloride'?

• Na + Cl → NaCl
• 2Na + Cl₂ → 2NaCl
• Na + Cl₂ → NaCl₂
• 2Na + 2Cl → 2NaCl

What is the correct chemical formula for aluminum sulfate?

• AlSO₄
• Al₂(SO₄)₃
• Al₃SO₄
• AlS₃O₄

In the reaction N₂ + 3H₂ → 2NH₃, how many hydrogen molecules are needed to react completely with one nitrogen molecule?

• 1
• 2
• 3
• 6

Which of the following is NOT a diatomic element?

• Oxygen
• Nitrogen
• Chlorine
• Neon

What does the subscript in a chemical formula represent?

• The number of atoms of an element in one molecule
• The number of molecules in the reaction
• The charge of the ion
• The atomic number of the element

Tags

NGSS.MS-PS1-1

In the reaction 2Al + 3Cl₂ → 2AlCl₃, what is the mole ratio of Al to Cl₂?

• 1:1
• 2:3
• 1:3
• 2:1

Which term best describes NaCl in an aqueous solution?

• Molecule
• Atom
• Formula unit
• Diatomic element

What is the molar mass of Ca(NO₃)₂?

• 164 g/mol
• 102 g/mol
• 132 g/mol
• 148 g/mol