Pt.2 Chemistry CH1 Quest.

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Grandma just finished number14 and will go on to number 15. 15. How many significant figures are in each of the following? (A) 1.01g ans. 15. (A)3 significant figures---The 'zero' nested between two nonzero (and hence significant) digits is significant. (B) 200.0s ans. 15. (B) 4 significant figures--The final zero is after the decimal point; therefore, it is significant. The other 'zeros' are nested between significant digits and are therefore significant. (C) 0.0021m ans. 15. (C) 2 significant figures---All 'zeros' are just placeholders. (D)0.0230k ans. 15. (D) 3 significant figures---The first two 'zeros' are placeholders. The last 'zero is significant as it is to the right of the decimal and ends the number. 16. If the graphic representation (which is a hump showing exothermic or endothermic reactions showing the energy levels in a chemical reaction. (With this graph the reactants are on a higher position with an arrowed line inside the hump marked with an a in the middle reaching down to that reactant line halfway down inside touching the dotted straight line from the reactants line to the hump line coming down and across with a dotted line half way marking with a solid line the products straight outside of the hump drawn as a hump or curve down to form the product line An arrowed line with a little b in the middle goes from the top reactants line to the dotted products line. That dotted line is only halfway across instead of the full reactants line. This is the same for what the chapter shows. 16. asks If the graphic representation of the energy levels of the reactants and products in a chemical reaction look like this (Be sure to read again the difference's.) (A) there is an exothermic reaction (B) there is an endothermic reaction (C) the 'a' portion is the energy given off (D) the 'b' portion is called the activation energy ans. 16. (A) The reaction is exothermic because the reactants have a higher potential energy than the products. 17. The amount of mass per unit volume refers to the (A) density (B) specific weight (C) volume (D) weight ans. Density is defined as mass per unit volume. 18. A baking powder can carry the statement "ingredients corn starch, sodium bicarbonate, calcium hydrogen phosphate, and sodium aluminum sulfate." Therefore, this baking powder is (A) a compound (B) a mixture (C) a molecule (D) a mixture of elements (answer in next lesson)