3. 1.3 An apparently empty test tube is submerged, mouth downward in water. Only a small volume of water rises into the tube, which is actually filled with invisible matter –air.
6. A solid can be either crystalline or amorphous . Which one it is depends on the internal arrangement of the particles that constitute the solid. Solid Amorphous Solid Crystalline Solid Particles lack a regular internal arrangement Particles exist in regular, repeating three-dimensional geometric patterns . Glass, plastics, gels Diamond, metals, salts
23. Example Sugar and fine white sand. The amount of sugar relative to sand can be varied. The sugar and sand each retain their own properties. Heterogeneous Mixture A heterogeneous mixture consists of 2 or more phases.
26. Mixture of iron and sulfur Compound of iron and sulfur Formula Has no definite formula: consists of Fe and S. FeS Composition Contains Fe and S in any proportion by mass. 63.5% Fe and 36.5% S by mass. Separation Fe and S can be separated by physical means. Fe and S can be separated only by chemical change.
27.
28. 1.6 Classification of matter: A pure substance is always homogeneous in composition, whereas a mixture always contains two or more substances and may be either homogeneous or heterogeneous.
66. In a chemical change new substances are formed that have different properties and composition from the original material.
67. Heating a copper wire in a Bunsen burner causes the copper to lose its original appearance and become a black material. Formation of Copper(II) Oxide Heating a copper wire in a Bunsen burner causes the copper to lose its original appearance and become a black material. The black material is a new substance called copper(II) oxide. Copper is 100% copper by mass. Copper (II) oxide is: 79.94% copper by mass 20.1% oxygen by mass. The formation of copper(II) oxide from copper and oxygen is a chemical change. The copper (II) oxide is a new substance with properties that are different from copper.
68. Formation of Copper(II) Oxide Copper(II) oxide is made up of Cu 2+ and O 2- 4.2 Neither Cu nor O 2 contains Cu 2+ or O 2- A chemical change has occurred.
69. Water is decomposed into hydrogen and oxygen by passing electricity through it. Decomposition of Water The composition and physical appearance of hydrogen and oxygen are different from water. The hydrogen explodes with a pop upon the addition of a burning splint. The oxygen causes the flame of a burning splint to intensify. They are both colorless gases. But the burning splint is extinguished when placed into the water sample.
96. An Example of the Difference Between Heat and Temperature A form of energy associated with small particles of matter. A measure of the intensity of heat, or of how hot or cold a system is.
97. Twice as much heat energy is required to raise the temperature of 200 g of water 10 o C as compared to 100 g of water. 200 g water 20 o C A 100 g water 20 o C B heat beakers temperature rises 10 o C 100 g water 30 o C 200 g water 30 o C 4184 J 8368 J
100. 4.3 H 2 + O 2 have higher potential energy than H 2 O Electrolysis of Water Burning of Hydrogen in Air energy is given off energy is absorbed higher potential energy lower potential energy
101. Law of Conservation of Energy Energy can be neither created nor destroyed, though it can be transformed from one form of energy to another form of energy.