Draw a structure of Beryllium Hydride.
Include:
Valence Electrons
The name of the molecular geometry shape
bent
Describe the difference between a limiting reactant and an excess reactant.
A limiting reactant is used up first when a reaction is completed. We can only make as much product as this reactant allows.
An excess reactant remains after a reaction is completed, and if we added more of the limiting reactant, more product could be made.
How many moles of Magnesium are in 3.01 x 1022 atoms of Magnesium?
0.05 moles
Describe the difference between reduction and oxidation.
Reduction is the gain of electrons from an oxidizing agent (this will become more negative than before)
Oxidation is the donation of electrons from a reducing agent (this will become less negative than before)
OR: reduction ends in a cation
oxidation ends in an anion
pH 6 or lower
dry texture
good electricity conductors in water
sour taste
most are corrosive
donate a proton
form conjugate bases in neutralization reactions
turn blue litmus paper red
no color / clear when phenolpthalein is added
Draw a structure of Triiodide.
Include:
Valence Electrons
The name of the molecular geometry shape
Explain what the term aqueous means.
a substance that contains water either as a solvent or some other medium
dissolved in solution with or of water
2 Al + 6 HBr --> 2AlBr3 + 3 H2
When 3.22 moles of Al reacts with 4.96 moles of HBr, how many moles of H2 can be formed?
2.48 moles of H2 can be formed.
Identify the acid, base, conjugate acid and conjugate base in the following neutralization reaction.
HCl + NaOH --> NaCl + H2O
HCl is the acid
NaOH is the base
NaCl is the conjugate base
H2O is the conjugate acid
Name 3 characteristics of bases.
turn red litmus paper blue
slippery texture
bitter taste
most are not corrosive
most do not conduct electricity well
form conjugate acids in neutralization reactions
turn pink with phenolphthalein
Draw a structure of Boron Trichloride.
Include:
Valence Electrons
The name of the molecular geometry shape
trigonal planar
From the following molecular equation, devise the net ionic equation.
Mg(NO3)2 (aq) + Na2CO3 (aq) -->
MgCO3 (s) + NaNO3 (aq)
Mg+2 (aq) + CO3-2 (aq) --> MgCO3 (s)
How many moles are there in 28 grams of Carbon Dioxide?
0.64 moles
In your own words, describe Hess's Law and its meaning or significance.
the energy change in an overall chemical reaction is equal to the sum of the energy changes in the individual reactions.
Give 2 examples of an endothermic reaction and 2 examples of an exothermic reaction.
All 4 examples must be accurate in order to get points.
Endothermic: ice melting, instant cold pack, photosynthesis, baking bread, etc.
Exothermic: ice freezing, instant heat pack, cellular respiration, nuclear fission, etc.
Draw a structure of Nitrogen Trihydride.
Include:
Valence Electrons
The name of the molecular geometry shape
trigonal pyramidal
Calculate the percent yield of a reaction if the theoretical yield is 10.5 grams of NaCl and the actual yield is 6.79 grams of NaCl.
Is the value you calculated considered to be a good percent yield? Describe why or why not.
About 65% yield
This is "mediocre". Percent yield measures how efficient or successful a reaction is. If we could make 10.5 grams of product and we only made 6.79 grams of product, there must have been some errors that occurred.
A 63.5 g sample of an unidentified metal absorbs 355 J of heat when its temperature changes by 4.56 C. Calculate the specific heat capacity of the metal.
1.23 J/gC
Find the value of the missing variable:
A student must use 225 mL of hot water in a lab procedure in order to raise the temperature of that 225 mL of water from 20 C to 100 C.
q = 75,240 Joules
q is heat energy
What is Avogadro's Number? (give the value and units)
What does it represent?
Both must be correct for points!
6.022 x 1023 atoms/molecules/particles
It represents the number of atoms/molecules/particles in one mole of any substance
Draw a structure of Methane (CH4)
Include:
Valence Electrons
The name of the molecular geometry shape
tetrahedral
When 8.00 grams of Pb(C2H3O2)2 are heated, 1.14 grams of water are driven off. Find the chemical formula for the hydrate.
Pb(C2H3O2)2 . 3H2O
750.0 g of water that was just boiled (heated to 100.0 C) loses 78.45 kJ of heat as it cools. What is the final temperature of the water?
75 C
Identify the oxidizing agent, reducing agent, reduced product and oxidized producct in the following chemical equation:
2Cs + Br2 --> 2CsBr
this is not a redox reaction!
Neptunium-237 undergoes 3 alpha decays and 2 beta decays. Write the nuclear equation to show the decay series as well as the element it becomes.
225/89 Ac