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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 Make up matter on earth and in space Represented by a chemical symbol 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 |