STAAR Day Review

Rearranging Atoms

100

What is true of all chemical reactions?

• Atoms rearrange themselves to form new molecules.
• Reactants combine together to form a single new product.
• Atoms change to other atoms and form new molecules.
• Energy is released to the surrounding.
• All of the above.

Atoms rearrange themselves to form new molecules. 

200

What is an acid?

What is the difference between a strong acid and a weak acid?

An acid contains a H⁺ that can easily come apart in water.

Strong acids come apart completely in water, weak acids do not. 

300

What arethe chemical formulae for the following compounds?

Calcium oxide

Iron(III) fluoride

Nickel(II) nitride

CaO

FeF₃

Ni₃N₂

400

Balance the following reaction and determine what type of reaction it is:

__C₆H₆(aq) + __O₂(g) -> __CO₂(g) + __H₂O(g)

Reaction Type: ______________________________

2C₆H₆(aq) + 15O₂(g) -> 12CO₂(g) + 6H₂O(g)

Combustion

500

Write out the following neutralization reaction:

Hydrobromic acid reacts with magnesium hydroxide

2HBr(aq) + Mg(OH)₂(s) -> 2H₂O(l) + MgBr₂(aq)

Stoichiometry

100

In the following reaction, what's the molar ratio between oxygen and carbon dioxide?

4C₂H₃Br₃ + 11O₂ → 8CO₂ + 6H₂O + 6Br₂

11 mol O₂ /8 mol CO₂

200

If 1 mol of each reactant is allowed to react in the following manner, which would be the limiting reactant?

                 2SO₂(g) + O₂ -> 2SO₃(g)

SO₂

More of it is consumed, so it will run out first. 

300

How many mol of H₂O are produced when 20.0 mol of O₂ react according to the following reaction:

4C₂H₃Br₃ + 11O₂ → 8CO₂ + 6H₂O + 6Br₂

10.9 mol

400

A patient has 7.35 mg of zinc in her 6.34 L of blood. What is this patient's blood-zinc levels in mM?

0.0177 mM

500

What mass of sulfur dioxide was consumed if 12.4 g of sulfur trioxide forms in the following reaction with excess oxygen?

       2SO₂(g)       +        O₂        ->       2SO₃(g)

  64.058 g/mol      31.998 g/mol       80.057 g/mol

9.92 g

Into and Around the Atom

100

How many valence electrons do the following atoms have:

Carbon

Potassium

Sulfur

Carbon   4

Potassium    1

Sulfur    6

200

How many orbits does a calcium atom have?

Four orbits!

It's in the fourth period

300

What is the variable for wavelength? How does the wavelength of a photon change with:

increasing frequency

increasing energy

λ

In both cases, wavelength decreases!

400

Draw the Lewis structure of AsO₂^-.

 

500

Order these atoms by increasing atomic radii:

Cl^-     Ar      K⁺

Opposite!

K⁺      Ar      Cl^-

(More electrons means more repulsion, and thus larger)

Nuclear Chemistry

100

What is radioactivity? 

(Your answer must include the two most important points!)

A spontaneous change of the nucleus that releases energy.

200

Why is ionizing radiation so dangerous?

It can take an electron off of water's atoms and cause it to be super reactive, which is harmful to the body!

300

Write the equation for the following particle undergoing beta decay:

²³⁹₉₃ Np

²³⁹₉₃Np -> ⁰_-1e + ²³⁹₉₄Pu

400

A radioactive 300.0-g sample of zirconium has a half-life of 13.5 minutes. How much of this sample is left after 30.0 minutes?

N_t = N₀e^-kt

64.3 g

500

How much energy is released per mole in the following fusion reaction:

²₁H + ³₁H -> ⁴₂He + ¹₁n

²₁H = 2.01410 amu

³₁H = 3.01605 amu

⁴₂He = 4.00260

¹₁n = 1.00866

5.03015 amu -> 5.01126

Change of 0.01889

1.71 x 10¹² J

Semester One

100

What was the plum-pudding model of the atom? What was the experiment that disproved this model?

The plum-pudding model stated that atoms have an evenly distributed mass rather than a dense mass in the center (nucleus). The gold foil experiment shows that particles bounce of the atom, thus proving there is a dense center. 

200

Which of the following points about Dalton’s Atomic theory is false?

• Everything is made up of tiny particles called atoms.
• Atoms cannot be created, destroyed, or subdivided.
• All atoms of a given element are identical to each other in all properties.
• Atoms can never change into atoms of other elements.

Atoms can never change into atoms of other elements.

Nuclear chemistry shows us that this can happen!

300

A molecule was found to have an empirical formula of NH₃. Which of the following cannot be the molar mass of this compound?

• 34.1 g/mol
• 85.2 g/mol
• 93.7 g/mol
• 136.2 g/mol

93.7 g/mol

400

How many molecules are in 174.0 g of the compound Fe₂Cl₃? 

4.806 x 10²³

500

500.0 g of zinc is heated by 3.40 kJ. If the sample starts at 4.00°C, what is the final temperature of the sample? Theat specific heat of zinc is 0.387 J/g*K

21.57^OC