Stoichiometry Pre-assessment

A balanced chemical equation allows one to determine the

• mole ratio of any two substances in the reaction.

• energy released in the reaction.

• electron configuration of all the elements in the reaction.

• mechanism involved in the reaction.

Tags

NGSS.HS-PS1-7

The coefficients in a chemical equation represent the

• masses, in grams, of all reactants and products.

• relative numbers of moles of reactants and products.

• number of atoms in each compound in a reaction.

• number of valence electrons involved in the reaction.

In the equation 2Al₂O₃ ----> 4Al + 3O₂, what is the mole ratio of aluminum to oxygen?

• 10:6

• 3:4

• 2:3

• 4:3

Tags

NGSS.HS-PS1-7

You know 1000 mg = 1 g.  Convert 2.5 grams into milligrams.

• 25 mg
• 25,000 mg
• 250 mg
• 2500 mg

How many molecules are in 2.5 mol of NaCl?

• 1.51x10²³
• 146
• 4.15
• 1.51x10²⁴

Tags

NGSS.HS-PS1-7

How many steps are in a gram to mole conversion?

• 1
• 2
• 3
• 4

If an atom of Fluorine has an atomic mass of 19 amu, it has a Molar mass of ____

• 19 lbs.
• 19 kg
• How am I supposed to know?
• 19 g/mol

What is the molar mass of table salt (NaCl)?

• 116.886 g/mol
• 35.453 g/mol
• 22.990 g/mol
• 58.443 g/mol

Which of the following dimensional analysis setups will correctly convert 4.00x10²³atoms of cobalt to moles of cobalt? How many moles of colbalt are there?

• setup B : 0.6644mol Co
• setup A: 2.41x10⁴⁷mol Co
• setup A : 0.664mol Co
• setup B: 2.41x10⁴⁷mol Co

B₂H₆ + 3O₂ -->2 HBO₂ + 2 H₂O

What mass of O₂ will be needed to burn 36.1 g of B₂H₆?

• 13.8 g O₂

• 3.86 mol of O₂

• 124 g O₂