Which of the following statements is one of the postulates in Dalton’s atomic theory?
a. All compounds are composed of multiple elements combined together.
b. Atoms of one element cannot be changed into another element through a chemical reaction.
c. Atoms of one element can be changed into atoms of another element through a chemical reaction.
d. Atoms of different elements can physically mix together
Answers: 1
Chemistry, 22.06.2019 06:40
Which statement correctly describes metallic bonds? a. they form when certain atoms lose electrons and other atoms gain electrons. b. they involve an attraction between anions and cations. they always involvpoth a metal and a nonmetal. d. they can only form between atoms of the same element. e. they form because electrons can move freely between atoms.
Answers: 3
Chemistry, 22.06.2019 07:30
The scheme below is from a series of reactions that are part of a synthesis of vitamin a. answer the following questions with reference to this scheme. (i) what is "reagent a"? (ii) draw a step-by-step mechanism which explains the formation of compound c from compound b (iii) which reagents would you use to form compound e from compounds c and d (reagents b and c)? for each reagent suggested above in (ii) explain the role of the reagent in the reaction to (iv) form compound e. you may wish to do this by drawing a mechanism. 1. addition of reagent a но reagent a 2. н,о" thо oh нон-с compound a. compound b. compound c .ch-оh 1. reagent b "сно 2. reagent c сh oh compound e. compound d.
Answers: 2
Chemistry, 22.06.2019 12:00
1. if you have a gas at 127 degrees c, what is it's absolute temperature (kelvin)? a. 200kb. 300kc. 400kd. 500k2. if you had a gas whose absolute temperature measured 45 k, what is that temperature in celsius? a. -228 cb. -300 cc. 125 cd. 112 c
Answers: 2
Chemistry, 22.06.2019 12:00
Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.
Answers: 2
Which of the following statements is one of the postulates in Dalton’s atomic theory?
a. All compo...
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