Physical properties and chemical properties – Experiment 5

Performance objectives To observe the appearance of several metals and nonmetals. To determine the boiling points of methanol and an unknown liquid. To determine whether a solid is soluble or insoluble in water. To determine whether a liquid is soluble or insoluble in water. To determine whether a substance is undergoing a physical or chemical change. To gain experience in determining a boiling point and observing test tube reactions.

discussion The classification of matter according to its physical and chemical properties. A heterogeneous mixture has physical and chemical properties that vary within the sample. A homogeneous mixture has constant properties although the properties can very from sample to sample. A pure substance is either an element or a compound – all substances have constant And predictable properties.

Discussion A physical property makes reference to the characteristic of matter that can be observed without changing the composition of the substance. A chemical property reference matter’s property that can change during chemical reactions. In this experiment, physical change of matter will be observed for substances that will undergo change of state, a temporary change of color, or a simple change in volume when two solutions are added together. Chemical change will be observed when substances react to release gas, undergo permanent change in color, or forms an insoluble substance when two solutions are added together.

Equipment Ring stand 250-mL beaker Wire gauze Evaporating dish 400-mL beaker Test tube brush 16 x 150 mm test tube Test tube holder Boiling chips Wash bottle with dist. water 110 deg. C thermometer Split cork 13 x 100 mm test tubes (6) and rack Crucible tongs

chemicals Small vials with samples of cobalt, hydrogen, magnesium , neon, oxygen, silicon, sulfur, tin, zinc Methyl alcohol, CH3OH Boiling point unknown Copper (II) sulfate, solid crystals, CuSO4 Sucrose, solid crystals C12H22O11 Amyl alcohol, C5H11OH Copper wire, heavy gauge Cu Iodine, solid crystals I2

Chemicals Ammonium bicarbonate, solid NH4HCO3 Potassium bicarbonate, solid KHCO3 Sodium carbonate solution, 0.5 M Na2CO3 Sodium sulfate solution, 0.1 M Na2SO4 Dilute hydrochloric acid, 6 M HCl Calcium nitrate solution, 0.1 M Ca(NO3)2 Copper(II) nitrate solution, 0.1 M Cu(NO3)2 Ammonium hydroxide solution, 6 M NH4OH

Procedure Physical Properties Physical State and Color Observe vials of the following elements and record your observations in the Data Table. Classify the element as a metal, a nonmetal, or a semimetal. cobalt (g) silicon hydrogen (h) sulfur magnesium (i) tin manganese (j) zinc neon oxygen

procedure 2. Boiling Point (a) Place a 400-mL beaker on a wire gauze, and support it on a ring stand. Add 300 mL of distilled water to the beaker, bring to a boil, and shut off the burner.

Procedure 2. Boiling Point (a) Put about 20 drops of methyl alcohol into a 16 x 150 mm test tube. Add a boiling chip and place the tube in the beaker of hot water.

Procedure 2. Boiling Point (a) Suspend a thermometer about 1 cm above the liquid. After the alcohol begins to boil in the test tube, record the boiling point temperature (+/- 0.5 deg. C) when alcohol drips from the tip of the thermometer every few seconds (Fig 5.2).

procedure 3. Solubility of a Solid in Water Add 20 drops of distilled water in two test tubes. Place a crystal of copper sulfate in one test tube, and a crystal of sucrose ( sugar ) in the other. Shake the test tubes briefly to dissolve the crystals. State whether each solid is soluble or insoluble in water.

procedure 4. Solubility of a Liquid in Water Add 20 drops of distilled water in two test tubes. Add a few drops of methyl alcohol to one test tube, and amyl alcohol to the other. Shake the test tubes briefly to mix the liquids. State whether each liquid is soluble or insoluble in water.

Procedure B. Chemical Properties Reactions of Element (a) Inspect a 5-cm piece of copper wire. Hold the wire with crucible tongs, and heat the wire until it glows red. Allow the wire to cool and inspect once again. Classify your observation as a physical change or chemical change.

procedure B. Chemical Properties (b) Place a few small crystals of iodine in a dry 250-mL beaker. Cover the breaker with an evaporating dish and place ice in the dish (Figure 5.3). Support the beaker on a ring stand, and heat the iodine slowly.

Procedure B. Chemical Properties (b) Notice the vaporization of the iodine crystals and the vapor deposits on the bottom of the evaporating dish. Classify your observation as a physical change or chemical.

Procedure 2. Reactions of Compounds Put a pea-sized portion of ammonium bicarbonate into a dry test tube. Heat the test tube gently as illustrated in Figure 1.1, and note any changes including odor. Classify your observation as either a physical change or chemical change.

procedure 2. Reaction of Compounds (b) Put a pea-sized portion of potassium bicarbonate into a dry test tube. Heat the test tube gently as shown in Figure 1.1 , and record any changes. Classify your observation as either a physical change or chemical change.

procedure 3. Reactions of Solutions Put 20 drops of sodium carbonate into a test tube and 20 drops of sodium sulfate in a separate test tube. Add several drops of dilute hydrochloric acid to each test tube, and record any changes. Classify your observation as a physical change or chemical change.

procedure 3. Reactions of Solutions (b) Put 20 drops of calcium nitrate into a test tube and 20 drops of copper(II)nitrate in a separate test tube. Add several drops of dilute ammonium hydroxide to each test tube, and not any changes. Classify your observation as a physical change or chemical change.