mole concept

What is the mass of 6.02 x 10²³ platinum atoms? Round to the nearest hundredths place.

• 30.97 g

• 106.42 g

• 140.91 g

• 195.09 g

A student needs 65.0 g of copper(II) chloride for an experiment. How many atoms of copper is this?

• 2.91 x 10^23 atoms

• 3.91 x 10^25 atoms

• 2.35 x 10^23 atoms

• 4.70 x 10^23 atoms

Tags

NGSS.HS-PS1-7

The molecular formula for a carbon and hydrogen compound is C₈H₁₈. What is the empirical formula?

• C₈H₁₈

• C₉H₄

• C₁₈H₈

• C₄H₉

Identify the limiting reagent when 6.00 moles HCl combines with 5.00 moles Mg to form MgCl₂.
 
1 Mg +  2 HCl --> 1 MgCl₂  +  1 H₂   
 

• Mg
• H₂
• MgCl₂
• HCl

Tags

NGSS.HS-PS1-7

When 12 moles of O₂ reacts with 6 moles of C₁₀H₈, what is the limiting reactant?  
1 C₁₀H₈ + 12 O₂ --> 10 CO₂ + 4 H₂O

• Oxygen
• C₁₀H₈
• Water
• Carbon Dioxide

Tags

NGSS.HS-PS1-7

If one Monster energy drink contains 0.16 g of caffeine, how many moles of caffeine do we consume when we drink 1 can? The chemical formula for caffeine is C₈H₁₀N₄O₂.

• 194 mol

• $1.57\ \times10^{-3}\ mol$

• 
  

  $8.2474\times10^{-4}\ mol$

• $3.14\ \times10^{-3\ }mol$

A container with a volume of 893 L contains how many moles of air at STP?

• 2.5 x 10^-2 mol

• 39.9 mol

• 22.4

• 2.7 x 10^-2 mol

• A

• B

• C

• D

• A

• B

• C

• D

• A

• B

• C

• D