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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: a new element being formed a chemical reaction an ionic bond between two covalent atoms 4. Which of the following is NOT an example of a chemical change? burnt toast torn paper sodium and water reacting cooking eggs in a pan Which of the following IS an example of a chemical change? 5. Walking your dog fireworks exploding a broken pencil taking out the trash 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 |