d. fading a pair of jeans 3. What is 0.500 inches expressed in cm in the proper
ID: 568064 • Letter: D
Question
d. fading a pair of jeans 3. What is 0.500 inches expressed in cm in the proper number of significant figures? a. 1.969x10 1 cm b. 1.27 cm c. 1.270 cm d. 1 cm e. None of the previous answers. 4. Which of the following quantity varies in ions? a. Number of neutrons b. Number of electrons c. Number of protons d. All of the above can change e. None of the previous answers. 5. What is an endothermic reaction? a. One that absorbs heat b. One that requires a high temperature c. One that requires at a low temperature d. One that releases heat e. None of the above describes an endothermic reaction.Explanation / Answer
1. 12 inches= 1 ft, 1 ft=0.3048m, 1m =100cm
hence 12 inches= 0.3048m= 30.48 cm
0.5 inches =0.5*30.48/12= 1.27 cm ( b is correct)
2. when an atom becomes an ion, electrons are going to get added or removed depending upon whether the atom is electronegative or electropositive. So there will be change in electrons.
3. Endo thermic reaction is one where heat is absorbed during the course of reaction. so a is correct. In case of endothermic reactions, when temperature is increased, to compensate for the effect of temperature, the reaction proceeds forward. So endothermic direction is preferred.
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