The mass ca(Oh)2 needed to produce 1.5 l of 0.25 solution is calculated as follows
find moles
=moles = molarity x volume
moles is therefore = 1.5 x 0.25 = 0.375 moles
mass = moles x molar mass
0.375mol x 74.09 g/mol = 27.78 grams
Answer:
e. Mg₃N₂(s) + 6H₂O(l) → 3Mg(OH)₂(s) + 2NH₃(g)
Explanation:
All the following are oxidation–reduction reactions except:________
a. H₂(g) + F₂(g) → 2HF(g). Redox. H is oxidized and F is reduced.
b. Ca(s) + H₂(g) → CaH₂(s). Redox. Ca is oxidized and H is reduced.
c. 2K(s) + 2H₂O(l) → 2KOH(aq) + H₂(g). Redox. K is oxidized and H is reduced.
d. 6Li(s) + N₂(g) → 2Li₃N(s). Redox. Li is oxidized and N is reduced.
e. Mg₃N₂(s) + 6H₂O(l) → 3Mg(OH)₂(s) + 2NH₃(g). Not redox. All the elements have the same oxidation number
Air is a mixture of gases like nitrogen, oxygen and traces of other gases like argon and many others. To improve this experiment, the mixture should be separated into its components to avoid contamination. In order to achieve this, you can use the cryogenic process, which is a distillation process at very low temperatures. In this case, you can use pure nitrogen or pure oxygen for your experiment.
Answer:
The student failed to rinse the buret with KMnO₄ solution after rinsing it with distilled water.
Explanation:
In a titration, the equivalent moles of titrant must be the same than analyte. If the student calculates an amount of moles of H₂O₂ that is larger than the actual value:
The student failed to wear goggles <em>FALSE. </em>The use of goggles doesn't change the results in the lab but you must use it!
The student did not swirl the flask appropriately and therefore stopped short of the endpoint. <em>FALSE. </em>The stopped short of the endpoint would explain a lower concentration of the real value.
The student failed to rinse the buret with KMnO₄ solution after rinsing it with distilled water. <em>TRUE. </em>If you don't rinse the buret with KMnO₄ solution the concentration of this solution in the buret will be lower than real concentration doing you spend more titrant volume overestimating the amount of H₂O₂ moles.
The student added an extra 15 mL of distilled water to the H₂O₂ solution. <em>FALSE. </em>The addition of water doesn't change the amount of H₂O₂ moles in the solution.
I hope it helps!
Answer:
270
Explanation:
Once you add more mass to something the mass doesn’t go away you add more mass.
hope this helps!