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1.Mrs. Davis was doing an experiment. She mixed two substances together in a flask and noticed that the beaker became very cold. Cold enough to form ice crystals on the outside of the beaker. Mrs. Davis concluded that: No type of reaction occurred This may be evidence of a chemical reaction A physical change occurred He just discovered how freezers work 2. Mrs. Ruble was doing a demonstration in class. She began boiling a beaker of water on a hot plate. Over a period of 5 minutes, students observed steam rising from the beaker and the level of water in the beaker had reduced from 200mL to 100mL. This is evidence of: a chemical change no change has occurred a change in the state of matter there's no way to know what has occurred 3.During a lab experiment, two students observed a faint glow in the beaker. Their substance began to change color and there was a slight odor detected.They concluded that they had just observed: an ionic bond between two covalent atoms a chemical reaction a new element being formed 4. Which of the following is NOT an example of a chemical change? sodium and water reacting cooking eggs in a pan burnt toast torn paper Which of the following IS an example of a chemical change? 5. fireworks exploding a broken pencil taking out the trash Cutting down a tree 6.To write a chemical symbol, the first letter is capitalized and any other letters are lowercase. True False Only in chemical formulas 7.How many chemical symbols (elements) are represented in the following formula: AgHNCaOPbCu 1 7 11 4 8. True or False Nails rusting is an example of a chemical change.
True False 9. Which of the following is NOT true about elements? They are pure substances Are made from other substances Represented by a chemical symbol Make up matter on earth and in space Which chemical reaction lab is being described? 10. Ammonium thyocianate and barium hydroxide were added together in a flask. A stopper was placed on top of the flask and the two chemicals were mixed together. As they mixed, the two solids became a liquid, produced a gas, and became very cold. The title of this lab was: Freezer Flask The Barium Hydroxide Change Chemical Reactions with White Flakey Solids Chemical Reactions with Cold Liquids 11.Mrs. Ruble made some Kool-aid. As she mixed the Kool-aid, she noticed the water changed color from clear to red. Mrs. Ruble concludes that: the water has changed into a brand new substance. a chemical reaction happened a chemical reaction did NOT happen since the color change was expected, and there were no otherchanges observed 12. Density is calculated by using the formula: __________ ÷ __________ = density pounds, inches length, width mass, volume watts, hour |