Answer:
51.3% Ca 48.7% F
Explanation:
MM CaF2 = 40.1+2x19 = 78.1 g/mol
MM Ca = 40.1 g/mol
MM F = 19 g/mol
% Ca = (40.1/78.1) x 100 = 51.3% Ca
% F = 100-51.3 = 48.7% F
Answer:
Substances which are non heat-resistant and volatile organic liquid with flammable vapor.
Explanation:
Bunsen Burner are used as a source of fire in the laboratory for heating up substances. Extra care however should be taken during heating in order to prevent fire or other forms of accidents.
Heating of mind heat resistant substances should be frowned at as the substances may get heated up and melt thereby exposing the liquid substances which may be flammable to fire thereby causing fire outbreak.
Heating of volatile organic liquid with flammable vapor should also be discouraged to prevent fire accidents.
Correct Answer: Option g: <span>adding salt to water lowers its freezing point
Reason:
Freezing point is a colligative property. When a non-volatile solution is present in solution, it's freezing point decreases. This is referred as depression in freezing point (</span>ΔTf<span>). Extent of lowering in freezing point is dependent on number of particles present in system. Mathematically it is expressed as:
</span>ΔTf = Kf X m
<span>
where, m = molality of solution
Kf = cryoscopic constant.
Hence, a</span><span>dding salt to water lowers the freezing point of solution.</span>
C. Model. It's a graphical model that displays one or more weather elements.
Answer:
pH = 2.46
Explanation:
Hello there!
In this case, since this neutralization reaction may be assumed to occur in a 1:1 mole ratio between the base and the strong acid, it is possible to write the following moles and volume-concentrations relationship for the equivalence point:
Whereas the moles of the salt are computed as shown below:
So we can divide those moles by the total volume (0.021L+0.0066L=0.0276L) to obtain the concentration of the final salt:
![[salt]=0.01428mol/0.0276L=0.517M](https://tex.z-dn.net/?f=%5Bsalt%5D%3D0.01428mol%2F0.0276L%3D0.517M)
Now, we need to keep in mind that this is an acidic salt since the base is weak and the acid strong, so the determinant ionization is:
Whose equilibrium expression is:
![Ka=\frac{[C_6H_5NH_2][H_3O^+]}{C_6H_5NH_3^+}](https://tex.z-dn.net/?f=Ka%3D%5Cfrac%7B%5BC_6H_5NH_2%5D%5BH_3O%5E%2B%5D%7D%7BC_6H_5NH_3%5E%2B%7D)
Now, since the Kb of C6H5NH2 is 4.3 x 10^-10, its Ka is 2.326x10^-5 (Kw/Kb), we can also write:
Whereas x is:
Which also equals the concentration of hydrogen ions; therefore, the pH at the equivalence point is:
Regards!
