Answer: A barrier should be created to overcome the atmosphere of the Venus, while launching spacecraft to Venus.
Explanation:
The atmosphere of Venus consists of 96.5% carbon dioxide, other composition includes nitrogen and other gases in trace amounts. The large amount of carbon dioxide in the atmosphere can extinguish the missile of the launcher of spacecraft thus it will become difficult in launch of spacecraft to the Venus.
Döbereiner grouped the known elements into <em>triads</em> (sets of three) so that
• The <em>atomic mass of the middle element</em> was approximately the average of the other two
• The <em>chemical properties of the middle element</em> were between those of the other two
• The <em>physical properties of the middle element</em> were between those of the other two
One example of a triad is Li – Na – K.
(a) Atomic mass of Na = 23.0 u
Average atomic mass of Li and K = (6.9 u + 39.1 u)/2 = 46.0 u/2 = 23.0 u
(b) Li reacts slowly with water. Na reacts rapidly. Potassium reacts violently.
(c) Melting point of Na = 371 °C.
Average melting point of Li and K = (454 °C + 330 °C)/2 = 784 °C/2
= 392 °C
Hello this answer isn't copied like the other one.
The answer is 85 calories.
Hope this helps.
Have a great day
:D
The given question is incomplete. The complete question is:
In the chemical reaction: , with 8 grams of and 16 grams of and the reaction goes to completion, what is the excess reactant and how much of that would remain?
A) 6 grams of
B) 7 grams of
C) 8 grams of
D) 12 grams of
E) 14 grams of
Answer: A) 6 grams of 
Explanation:
To calculate the moles :
According to stoichiometry :
1 moles of 
require 2 moles of
Thus 0.5 moles of will require=
of
Thus is the limiting reagent as it limits the formation of product and is the excess reagent.
(4.0-1.0) = 3.0 moles of are left unreacted
Mass of remained=
Thus 6.0 g of will remain.
