11th grade chemistry term test SEK

A) 6,0 moles of Li, contain less particles than B) 4,6x10²⁴ atoms of O. This statement is

• Is true

• Is false, B) contains more particles than A)

• Is false, both have the same number of particles

You have to find out how many atoms there are in 4,3 moles of NH3. Can you use the following operation?

 $4,3\ moles\ O\ \times\ \frac{1\ molecule\ NH3}{\ 6,02\ x\ 10^{23}\ moles\ NH3}$  

• Yes, we can

• No, we cannot because the numbers in the fraction are wrong
  

• No, we cannot because the units in the fraction are wrong

You have to find out how many atoms are there in 1,7 moles of N. Can you use the following operation?

 $7,1\ moles\ N\ \times\ \frac{6,02\ x\ 10^{23}\ atoms\ N}{\ 1\ mole\ N}$  

• Yes, we can, both units and numbers are correct

• No, we cannot because the numbers in the operation are wrong
  

• No, we cannot because the units in the fraction are wrong

You have to find out how many atoms are there in 5,0 moles of Ca. Can you use the following operation?

 $5,0\ moles\ Ca\times\ \frac{6,02\ x\ 10^{23}\ atoms\ Ca}{\ 1\ mole\ Ca}$  

• Yes, we can, both units and numbers are correct

• No, we cannot because the numbers in the operation are wrong
  

• No, we cannot because the units in the fraction are wrong

You find in a table the information:

m Al = 13 g/mol

(m= molar mass)

Can be read as:

• 1 mol of Al weighs 13 g

• 13 mols of Al weigh 1 g

• 1 g of Al is equal to 13 mols

The molecule of caffeine is the main ingredient in coffee to give you that energy boost you need. The operation to calculate its molar mass (m) is:

• 
  

  $m\ =\ mC\times4+mN\times8+mH\times10+mN\times4$

• $m\ =\ mC\times8+mH\times10+mN\times4+mO\times2$

• $m\ =\ mC+8+mH+10+mN+4+mO+2$

• $m\ =\ mC\times8\times mH\times10\times mN\times4\times mO\times2$

The statememt: 2 moles of Fe contain less particles than 2 moles of H₂O₂, is

• True, H₂O₂ contains 4 times more particles

• False, they contain the same number of particles

• False, Fe contains more particles

• It depends on the molar mass of each substance

What does the Law of Conservation of Mass state?

• The number of atoms never changes during a chemical reaction

• The number of atoms always changes during a chemical reaction

• The number of atoms sometimes changes during a chemical reaction

• The number of molecules never changes during a chemical reaction

What is the left part of a chemical equation called?
2H_{2 +} O₂ --> 2H₂O

• Reactants
• Products 
• Yields 
• Chemical Equation 

What is the right part of a chemical equation called...
2H_{2 +} O₂ --> 2H₂O

• Reactants
• Products 
• Yields 
• Chemical Equation 

Tags

NGSS.MS-PS1-5