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3 years ago

How many molecules of liquid methanol are in 10.00 mL of methanol, given its density is 0.7918 g/mL?

1 answer:

7 0

$d=0,7918\frac{g}{mL}\\ V=10mL \ \ \ \ \ \ \ \ \ \ \ m=dV=0,7918\frac{g}{mL}*10mL=7,918g\\\\ 6,02*10^{23} \ \ \ \ \ \ \ \Rightarrow \ \ \ \ 32g\\ N_{x} \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \Rightarrow \ \ \ \ 7,918g\\\\ N_{x}=\frac{6,02*10^{23}*7,918g}{32g}\approx1,49*10^{23}$

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Hydrocyanic acid, HCN, is a weak acid. (a) Write the chemical equation for the dissociation of HCN in water. (b) Identify the Br

12345 [234]

Answer: a) $HCN(aq.)+H_2O\rightleftharoons H_3O^+(aq.)+CN^-(aq.)$

b) $HCN$ : acid $CN^-$ :conjugate base.

And, $H_2O$ : base $H_3O^+$ : conjugate acid.

c) $HCN(aq.)+NaOH(aq)\rightleftharoons NaCN(aq.)+H_2O(l)$

d) $NaCN(aq)\rightarrow Na^+(aq.)+CN^-(aq)$

e) $NaCN(aq)+HCl(aq)\rightarrow NaCl(aq.)+HCN(aq)$

Explanation:

a) Weak acid is defined as the acid which does not completely dissociates when dissolved in water. They have high pH. These releases $H^+$ ions in their aqueous states.

The equation for the dissociation of $HCN$ acid is given by:

$HCN(aq.)+H_2O\rightleftharoons H_3O^+(aq.)+CN^-(aq.)$

b) According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.

For the given chemical equation:

$HCN$ is loosing a proton, thus it is considered as an acid and after losing a proton, it forms $CN^-$ which is a conjugate base.

And, $H_2O$ is gaining a proton, thus it is considered as a base and after gaining a proton, it forms $H_3O^+$ which is a conjugate acid.

c) Neutralization reaction is a reaction in which an acid reacts with base to produce salt and water.

$HCN(aq.)+NaOH(aq)\rightarrow NaCN(aq.)+H_2O(l)$

d) The chemical equation for dissociation of $NaCN$ in water.

$NaCN(aq)\rightarrow Na^+(aq.)+CN^-(aq)$

e) The chemical equation for the reaction of $NaCN$ and $HCI$

$NaCN(aq)+HCl(aq)\rightarrow NaCl(aq.)+HCN(aq)$

4 0

3 years ago

WILL GIVE BRAINLIEST ANSWER

OleMash [197]

The correct Answer based on my calculations is C

7 0

3 years ago

Read 2 more answers

what is the order of decreasing bond length for a C-C bond composed of the following molecular orbitals?I. sp^3 - sp^3II. sp^2 -

skelet666 [1.2K]

Answer:

The decreasing order of bond length in the carbon - carbon bonds will be:

$C-C>C=C>C\equiv C$

Explanation:

Bond length is defined as average distance between two nuclei of bonded atoms in a molecule.Bond length is inversely proportional to the number of bonds present between two atoms.

$\text{Bond length} \propto \frac{1}{\text{Number of bonds}}$ ...[1]

Bond energy is defied as amount of energy required to break apart the bond of 1 mole of molecule into their individual atom. Bond energy is directly proportional to the number of bonds present between two atoms.

$\text{Bond Energy} \propto \text{Number of bonds}$ ..[2]