Final review chemistry

Which statement is INCORRECT use of mole measurement?

• one mole of calcium is 40.01 grams.

• one mole of calcium is equals to 6.02 x 10²³ atoms

• two moles of CaCl₂ is equal to 6.02 x 10²³ molecules

• two moles of KI is equals to 166g

The number 6.02 x 10²³ is called...

• Planck's constant

• Fibonacci Number

• Euler's number

• Avogadro's number

Which has more molecules?

• 1 mole H₂O
• 1 mole Al(OH)₃
• 1 mole NaCl
• There are all the same

Tags

NGSS.MS-PS1-1

What is the molar mass of sodium?

• 11
• 23
• 45.98
• 3

What is the mass of one mole of aluminum?

• 27 g
• 13 g
• 54 g
• 14 g

What is the Law of Conservation of mass?

• Mass is created in a chemical reaction
• Mass is created in a physical change
• New chemicals formed from a chemical reaction have a larger overall mass than the original reactants
• Mass is never created or destroyed

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

In a reaction A + B ----> C,  reactant A has 5g and product  C has 9g. How many grams does reactant B should have? 

• 4g
• 5g
• 9g
• 14g

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

What is the Law of Conservation of Mass, and how does it relate to chemical reactions?

• Total mass of a closed system remains constant through time, regardless of other possible changes within the system

• Mass can neither be created nor destroyed rather, it can only be transformed from one form to another

• A property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force.

• It means that all chemical reactions must be properly balanced so there are the same number and type of each atom on each side of the reaction arrow.

Why must we balance chemical equations? 

• Our teacher said so
• to abide by the law of conservation of energy
• to abide by the law of conservation of mass

Tags

NGSS.MS-PS1-5

Balance this equation-
__P₄ + __O₂ --> __P₂O₃

• it is already balanced
• 2, 1, 3
• 1, 2, 3
• 1, 3, 2

Tags

NGSS.MS-PS1-5