Theories, Problems, Solutions

Hot Water

Crazy Horse — Thu, 04 Aug 2005 14:00:00 -0400

How much energy is required (in Joules) when the temperature of 3.6 grams of liquid water increases by 4 °C ?

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Oxidation Reduction

Crazy Horse — Sat, 30 Jul 2005 16:28:00 -0400

Balance the following oxidation-reduction equation:

NaHSO₄ + Al + NaOH ---> Na₂S + Al₂O₃ + H₂O

Half Life

Crazy Horse — Tue, 26 Jul 2005 11:00:00 -0400

If an enriched radioactive isotope has a half-life of 8 minutes, what proportion would be left after 24 minutes?

(1) .083

(2) .125

(3) .166

(4) .25

(5) .5

Oxidation and Reduction

Crazy Horse — Sat, 16 Jul 2005 14:07:00 -0400

Balance the oxidation-reduction equation below:

Cr₂O₃ + Na₂CO₃ + KNO₃ ---> Na₂CrO₄ + CO₂ + KNO₂

Precipitate?

Crazy Horse — Sat, 09 Jul 2005 11:16:00 -0400

A mixture of water and AgCl is shaken until a saturated solution forms. Then the solid is filtered, and 100 mL of 0.03 M NaBr. is added to 100 mL of the filtrate. Should a precipitate form?

Balanced Equatioins

Crazy Horse — Thu, 07 Jul 2005 22:49:00 -0400

Write complete and balanced equatons for each of the following reactions:

(1) P₂O₅ + H₂O --->

(2) NaCl + AgNO₃ --->

(3) H₂SO₄ + NaOH (limited)

(4) FeCl₂ + AgNO₃ --->

Coordination Compunds

Crazy Horse — Thu, 07 Jul 2005 10:19:00 -0400

Sketch and name all the possible linkage and stereoisomers of the following coordination compunds:

(a) [Pt(NH₃)₂(SCN)₂]

(b) [Co(en)(H₂NCH₂CO₂)₂]CI

Carbon Combustion

Crazy Horse — Fri, 01 Jul 2005 11:55:00 -0400

The heat of combustion for 1m of carbon to carbon dioxide is -410 kJ. How many kJ of heat would escape from the combustion of 60.0 g of carbon?

(1) -65 kJ
(2) -1680 kJ
(3) -2050 kJ
(4) -135 kJ

Polar Bonds

Crazy Horse — Mon, 20 Jun 2005 09:15:00 -0400

Which of these formulas contains the most polar bond?

(1) H-Br
(2) H-Cl
(3) H-F
(4) H-I

Excited Electrons

Crazy Horse — Sat, 18 Jun 2005 06:46:00 -0400

Which electron configuration represents the electrons of an atom in an excited state:

(1) 2-8-1
(2) 2-8-6
(3) 2-8-17-6
(4) 2-8-18-5