Answer:
B
Explanation:
Energy is released, when a gas changes to solid
Sodium Chloride is a compound.
Explanation:
Cadmium, nickel, chromium, and silver are sometimes used as protective platings. Metals have a wide range of corrosion resistance. The most active metals (i.e., those that tend to lose electrons easily)--such as magnesium and aluminum--corrode easily and are listed at the top of Table 2-1.
Answer:
Benzoic acid is the stronger acid
Explanation:
Weak acids do not dissociate completely in the solution. They exists in equilibrium with their respective ions in the solution.
The extent of dissociation of the acid furnising hydrogen ions can be determined by using dissociation constant of acid (
).
Thus for a weak acid, HA
The is:
![K_a= \frac{[A^-][H^+]}{[HA]}](https://tex.z-dn.net/?f=K_a%3D%20%5Cfrac%7B%5BA%5E-%5D%5BH%5E%2B%5D%7D%7B%5BHA%5D%7D)
The more the , the more the acid dissociates, the more the stronger is the acid.
Also,
is defined as the negative logarithm of .
So, more the , less is the and vice versa
All can be summed up as:
The less the value of , the more the is and the more the acid dissociates and the more the stronger is the acid.
Given,
of acetic acid = 54.7
of benzoic acid = 54.2
of benzoic acid < of acetic acid
So, benzoic acid is the stronger acid.
Answer:
89.34%
Explanation:
First, write a balanced reaction.
Mg3N2 + <u>6</u>H2O --> <u>3</u>Mg (OH)2 + <u>2</u>NH3
Next determine the moles of the known substance, or limiting reagent ( H2O)
n= m/MM
n ( H2O) = 4.33/(1.008×2)+16
n(H2O)= 0.2403
Use the mole ratio to find the moles of Mg(OH)2
0.2403 ÷2
n (Mg (OH)2) = 0.1202
Next, find the theoretical mass of Mg (OH)2 that should have been produced
m= n × MM
m= 0.1202 × (24.305 + (16×2) +(1.008 ×2))
=7.007g
To find percentage yield, divide the experimental amount by the theoretical amount and multiply by 100.
6.26/ 7.007 × 100
=89.34%
