Avogadro's Number
What is the value AND units for Avogadro's number?
6.02x1023atoms/mol
What are the units for molar mass?
g/mol
What are the units for molarity?
What do the period numbers (rows) tell you?
Shells
Which of the following is an empirical formula?
AlO3
C2H6
Na4(PO3)2
AlO3
How many particles are in 2 moles of a substance?
1.2E24 particles
What is the molar mass of CaCl2?
110g/mol
How many moles are in 14L at STP?
0.625moles
As the number of shells increase, a) the atomic radius (increases/decreases) and b) the ionization energy (increases/decreases)
Find the empirical formula if:
K₂S₂O₃
How many moles of sodium are in Na3PO4?
3
How many moles of Cu are in 3.4g of Cu?
0.0535mol
How many L in 1mol of a 0.4M solution?
2.5L
Rank O, F, Na, and Mg in terms of atomic radius.
Na>Mg>O>F
Find the empirical formula if:
C₃H₆NO
How many atoms are in 0.003mol of He?
1.806E21 atoms He
How many grams of MgCl2 are in 0.004moles?
0.377g
What is the molarity of a solution with 3 moles in 300mL?
10M
Rank Ca, K, Se, and Br from highest to lowest ionization energy AND justify why.
Br>Se>Ca>K
Because shells are same but number of valence e- increases
What is the molecular formula of a compound with an empirical formula of CH4 if the molar mass is 64g/mol?
C4H16
How many atoms of O are in 0.28 moles of O2?
3.37E23 atoms O
How many atoms of N are in 3g of N2?
1.29E23atoms N
0.57M
Rank Rb, Sr, P, and F in terms of atomic radius and give reasons (2).
Rb>Sr>P>F
Because Rb and Sr have a higher number of shells, but Rb has a lower positive nuclear charge
A 4.30 g sample of hydrated cobalt(II) chloride (CoCl₂·xH₂O) until all the water of hydration is driven off. The mass of the remaining anhydrous CoCl₂ is found to be 2.35 g. Find the hydrate formula.
CoCl₂·6H₂O