NSS Chemistry Part 15 Analytical Chemistry (Structural Questions) HKCEE and HKAL Past Paper Questions 1. HKCEE 1994 Q8b A student carried out some tests on an ionic compound X which was a white solid. The results obtained were summarized in the following flow diagram: (i) Based on the above information‚ deduce the cation and anion present in X. (ii) Describe how the flame test on X can be carried out in the laboratory. (6 marks) 1 2. HKCEE 1995 Q2 In each of the following
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resting neuron? Your answer: There are less sodium leak channels than potassium leak channels‚ and more of the potassium channels are open. 4. Discuss the relative permeability of the membrane to Na+ and K+ in a resting neuron. Your answer: Membrane permeability to sodium is very low because there are only a few sodium leak channels. The membrane is more permeable to potassium because of the higher number of potassium leak channels. 5. Discuss how a change in Na+ or K+ conductance would
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Percent By Mass Solution Problems 1. What is the percent by mass of a solution made by dissolving 0.49 g of potassium sulfate in 12.70 g of water? 2. What is the percentage concentration of 75.0 g of ethanol dissolved in 500.0 g of water? 3. A chemist dissolves 3.50 g of potassium iodate and 6.23 g of potassium hydroxide in 805.05 g of water. What is the percentage concentration of each solute in the solution? 4. A student wants to make a 5.00 % solution of rubidium chloride
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the color of the flame. Test it again by observing the flame through two pieces of cobalt blue glass held together. Record the flame color with the cobalt blue glass on a separate line. You will observe the solution of sodium chloride mixed with potassium chloride without the cobalt blue glass and then again with the cobalt blue glass. Record the color of the flame seen not two separate lines.
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Results and discussion: I. a. How would you compare that relative reactivity of Na and k -Sodium and potassium react somewhat similar when reacting with water however they are slightly different. Sodium moves because of the hydrogen coming off of it and has a low melting point while potassium’s reaction is faster and enough heat is produced to set light to the hydrogen coming off of it. Each leaves a pink color hue in the water. Discuss the similarities and differences in the behavior of the metals
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the unknown elements is the same as one of the known elements‚ then they are the same element. Materials * Samples of the following metallic salts * calcium chloride * copper chloride * iron chloride * lithium chloride * potassium chloride * sodium chloride * strontium chloride * unknown 1 * unknown 2 * Bunsen burner and accessories * Safety goggles * Lab apron * Splints soaked overnight in distilled water * 250 mL. beaker full of distilled
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will produce a pure‚ intense color when present in moderate concentration. Fertilizer[edit] Potassium nitrate is mainly used in fertilizers‚ as a source of nitrogen and potassium – two of the macronutrients for plants. When used by itself‚ it has an NPK rating of 13-0-44. Oxidizer[edit] Potassium nitrate is an efficient oxidizer‚ producing a lilac-colored flame upon burning due to the presence of potassium. It is one of the three components of black powder‚ along with powdered charcoal (substantially
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concentration of Potassium Hydroxide affecting the temperature of water that it is dissolved in. One person stirred in the different concentrations of Potassium Hydroxide while the other measured the temperature as it rose after the pellets dissolved. At times it was difficult to ensure that the pellets were completely dissolved within the solution. Raw Data Table: The temperature of water after dissolving different concentrations of Potassium Hydroxide in it. Concentration of Potassium Hydroxide (g/ml)
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decomposing potassium chlorate using the reaction below. If 138.6 g of KClO3 is heated and decomposes completely‚ what mass of oxygen gas is produced? KClO3 (s) --> KCl (s) + O2 (g) [unbalanced] Answer to Practice Problem #1: 1. Balance your equation first. 2KClO3 (s) --> 2KCl (s) + 3O2 (g) [balanced] 2. Convert from grams to moles using molar mass. To get moles from grams of potassium chlorate (KClO3):
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Date Performed: July 30‚ 2012 EXPERIMENT NO. 10 COMPOSITION OF POTASSIUM CHLORIDE ABSTRACT The aim of the experiment was to look for the percentage composition of the elements present in the decomposition of potassium chlorate (KClO3) and to find out what the residue after heating was. After performing the experiment the researchers found out that there were about 66.14% of potassium chloride (KCl) in KClO3‚ and they also deducted that the residue was actually KCl. _____________________
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