A. The bonds between the individual monomers of a polymer are broken by the addition of water molecules.
Two electron pairs is the answer
Answer:
Answer in explanation
Explanation:
a. Boron , element 5
Helium has 2 electrons, add to the other 3 to give 5.
Other group members are : Aluminum Al, Gallium Ga, Indium In , Thallium Tl and Nihonium Nh
b. Sulphur, element 16
Neon is 10 , add other 6 electrons to make 16
Other group members are: Oxygen O, selenium Se , Tellurium Te and Polonium Po
c. Lanthanum, element 57
Xenon is 54, add the other 3 electrons to give 57.
Other elements in group : Scandium Sc , Yttrium Y , Actinium Ac, Lutetium Lu and/or Lawrencium Lr
A reaction in which heat is evolved is an exothermic reaction while a reaction in which heat is absorbed is an endothermic reaction.
In the first case; Na2CO3 + H2SO4, we can see that this is an acid - base reaction therefore it is a neutralization reaction. Since the tube was hot after reaction, heat is given off so it is exothermic.
In the second case; NaOH + H2SO4, we can see that this is an acid - base reaction therefore it is a neutralization reaction. We are told that the tube is not hot but we don't know the initial temperature of the tube or if it was colder than it's initial temperature so we can not make any inference regarding whether the reaction is endothermic or exothermic.
Lastly, the reaction, NaCl + HC2H5OH does not occur so we mark "no reaction". We are told that the tube is not hot but we don't know the initial temperature of the tube or if it was colder than it's initial temperature so we can not make any inference regarding whether the reaction is endothermic or exothermic.
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It is 14, plug it in or use inverse equations. Since they're vertical angles they are the same value. 41 = 2x+13, 28 = 2x (subtract 13), 14 = x (divide by 2).
