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A 6.0 grams of NaOH is dissolved in distilled water to make 1.60 - liters of solution. What is the pH of the NaOH solution?
AW Na = 23 g/mol ; AW O = 16 g/mol ; AW H = 1 g/mol
11. Why is it not practical to use stainless steel to build structures such as bridges that are prone to corrosion?
a) Stainless steel will corrode quickly if the protective coating is broken.
b) The chromium used in stainless is too expensive.
c) Stainless steel is not strong enough.
d) The carbon used to make stainless steel is too expensive.
12. A galvanized nail is coated with what metal?
a) tin
b) chromium
c) aluminum
d) zinc
13. In the Factors that Affect Corrosion Lab what was the purpose of the layer of oil on top of the liquid in some of the experimental set-ups?
a) to coat the steel wool with a protective layer of oil
b) to prevent the water from evaporating
c) to prevent oxygen from dissolving in the water di to mix with the water to create an electrolyte solution for he redox reaction
14 Generally which of the following factors decreases the rate of iron corrosion?
a) the presence of salt
b) contact with a more reactive metal
c) acidic conditions
d) mechanical stress, such as bending
Which of the following types of batteries can be recharged?
a) alkaline dry cells
b) zinc chloride
c) nickel-cadmium (Ni-Cad)
d) mercury button battery
8. Hydrogen fuel cells:
a) are recharged by plugging them into an electrical outlet.
b) are recharged by filling the cell up with fuel, similar to filling up a gas tank.
c) cannot be recharged.
d) are recharged by using electricity to reverse the chemical reactions that occurred in the cell.
9. The following substance(s) must be present for the corrosion of iron to occur.
a) oxygen and carbon dioxide
b) water and carbon dioxide
c) oxygen and water
d) oxygen 1
0. In the redox reaction of the corrosion of iron which substance is reduced?
a) iron
c) iron(III) oxide
d) water
The cathode is:
a) the negative electrode where reduction takes place.
b) the positive electrode where reduction takes place.
c) the negative electrode where oxidation takes place.
d) the positive electrode where oxidation takes place.
5. In a Daniell cell with a zinc anode the positive charge that builds up in the zinc half- cell compartment is neutralized by:
a) positive ions migrating towards the anode. negative ions migrating towards the cathode.
c) negative ions migrating towards the anode.
d) positive zinc ions, Zn2*, being reduced to produce zinc atoms.
6. During electroplating the metal object to be plated is usually:
a) made the anode in the electrochemical cell.
b) the electrolyte is the electrochemical cell.
c) made the cathode in the electrochemical cell.
d) oxidized.
Explain why H+ and OH- have exceptionally high ionic mobility in Aqueous media. Show schematically.
What are the Names of alkenes groups
Equation to who the reaction of hex-1-ene to hexane with bromine water
Calculate Eºcell for the reactions below to be determine which are spontaneous as written:
a. Co(s) + H+(aq) → Co+2(aq) + H2(g)
b. Mn+2(aq) + Co+3(aq) → MnO2(s) + Co+2(aq) [acidic]
c. Ag(s) + Cu+2(aq) → Ag+(aq) + Cu(s)
9. By mass, a compound contains 28.9% potassium, 23.7% sulfur and the remainder is oxygen. What is the empirical formula of this compound?
10. The percent compositions are given for 2 antibiotics below. Find the empirical formula for each one:
a. 40.87% carbon, 3.72% hydrogen, 8.67% nitrogen, 24.77% oxygen and 21.98% chlorine.
b. 41.86% carbon, 4.65% hydrogen, 16.28% nitrogen, 18.60% oxygen and 18.60% sulfur.
11. Caffeine consists of 49.5% carbon, 5.15% hydrogen and 28.9% nitrogen and the rest is oxygen.
a. What is the empirical formula?
b. Given the molar mass of caffeine is 195g/mol, what is the molecular formula?
12. An ester is a compound with a pleasant odour. One of the esters was analyzed and the data is found below:
How many moles of sodium sulphite are in the 2.67g?
2. How many molecules of potassium acetate are in 4.55mol?
3. What is the mass of 1.76 x 1024 molecules of calcium phosphide?
4. a. How many molecules of aluminum hydroxide are in 2.45 mol?
b. How many atoms of oxygen are in 2.45mol of aluminum hydroxide?
5. What is the %mass of hydrogen in ammonium sulphate?
6. What is the % composition of dinitrogen tetrachloride?
7. What is the empirical formula of a compound made from 60% magnesium and 40% oxygen?
8. What is the empirical formula of a molecule whose percent composition is 21.6% sodium, 33.3% chlorine, and 45.1% oxygen?
