Answer:
conclusion
Explanation:
it can't be a hypothesis since tests are carried out to verify so it is not a theory
an introduction to an experiment only gives the basis of what we are investigating therefore nothing has been proven and the question is still unanswered
Answer:
Option D.
Explanation:
First we convert the given reactant masses into moles, using their respective molar masses:
- 4.00 g H₂ ÷ 2 g/mol = 2 mol H₂
- 6.20 g P₄ ÷ 124 g/mol = 0.05 mol P₄
0.05 moles of P₄ would react completely with (6*0.05) 0.3 moles of H₂. There are more H₂ moles than required, meaning H₂ is in excess and P₄ is the limiting reactant.
Now we<u> calculate how many PH₃ moles could be formed</u>, using the <em>number of moles of the limiting reactant</em>:
- 0.05 mol P₄ *
= 0.2 mol PH₃
Finally we <u>convert 0.2 mol PH₃ into grams</u>, using its <em>molar mass</em>:
- 0.2 mol PH₃ * 34 g/mol = 6.8 g
So the correct answer is option D.
Answer: The best way to promote the process are:
--> Add a bit of solid as a seed crystal.
--> Scratch the bottom of the flask gently with a stirring rod.
Explanation:
A crystal growth is seen is SUPERSATURATED solutions which contains more solute than it can normally dissolve at that given temperature. It is usually very UNSTABLE and capable of releasing the excess solute if disturbed, either by shaking or seeding with a tiny crystals.
Crystallization can be used for the separation of two salts with different solubilities as well as for purification of a soluble salt that contains insoluble solid impurities. Recrystallization improves the validity of the process. Crystallization can be initiated by:
--> Scratching the bottom of the flask gently with a stirring rod: scratching initiates crystallization by providing energy from the high-frequency vibrations.
--> Adding a bit of solid as a seed crystal: Seed crystals create a nucleation site where crystals can begin growth.
Kilo: a prefix used on metric units to indicate a multiple of 1000. For example 1kg = 1000 g
