A certain liquid has a density of 2.67 g/ cm3. what is the mass of 30.5 ml of this liquid? (

A 600.0 mL sample of 0.20 MHF is titrated with 0.10 MNaOH. Determine the pH of the solution after the addition of 600.0 mL of Na

Leona [35]

Answer: pH=12.69

Explanation:

${\text{Moles of HF}=Molarity\times {\text{Volume of solution in liters}}$

${\text{Moles of HF}=0.20M\times 0.6L=0.12 moles$

$HF\rightarrow H^++F^-$

Initial 0.12 0 0

Eqm 0.12-x x x

$K_a=\frac{[H^+][F^-]}{[HF]}$

$3.5\times 10^{-4}=\frac{x^2}{0.12-x}$

(neglecting small value of x in comparison to 0.12)

$x=4.2\times 10^{-5}$

Moles of $H^+=4.2\times 10^{-5}$

$NaOH\rightarrow Na^++OH^-$

${\text{Molesof NaOH}}=Molarity\times {\text{Volume of solution in liters}}$

${\text{Moles of NaOH}}=0.10M\times 0.6L=0.06 moles$

0.06 moles of NaOH will give 0.06 moles of $[OH^-]$

Now $4.2\times 10^{-5}$ moles of $OH^-$ will be neutralized by $4.2\times 10^{-5}$ moles of $H^+$ and $(0.06-4.2\times 10^{-5})=0.059$ moles of $OH^-$ will be left.

Molarity of $OH^-=\frac{0.059moles}{1.2L}=0.049M$

$pOH=-\log[OH^-]=-\log[0.049]=1.31$

pH = 14 - pOH= 14 - 1.31 = 12.69

5 0

2 years ago

Write the electron configurations for the following ions:

Ket [755]

Answer:

Co²⁺ : 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁷

Sn²⁺ : 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰

Zr⁴⁺ : 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶

Ag⁺ : 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 4d¹⁰

S²⁻ : 1s² 2s² 2p⁶ 3s² 3p⁶

Explanation:

Cobalt (Co): atomic number 27

The electronic configuration of Co in ground state:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁷

The electronic configuration of Co in +2 oxidation state (Co²⁺) :

1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁷

Tin (Sn): atomic number 50

The electronic configuration of Sn in ground state:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p²

The electronic configuration of Sn in +2 oxidation state (Sn²⁺) :

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰

Zirconium (Zr): atomic number 40

The electronic configuration of Zr in ground state:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d²

The electronic configuration of Zr in +4 oxidation state (Zr⁴⁺) :

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶

Silver (Ag): atomic number 47

The electronic configuration of Ag in ground state:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s¹ 4d¹⁰

The electronic configuration of Ag in +1 oxidation state (Ag⁺) :

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 4d¹⁰

Sulphur (S): atomic number 16

The electronic configuration of S in ground state:

1s² 2s² 2p⁶ 3s² 3p⁴

The electronic configuration of S in -2 oxidation state (S²⁻) :

1s² 2s² 2p⁶ 3s² 3p⁶

8 0

2 years ago

Read 2 more answers

How many moles of chromium metal equal 7.52 × 1022 atoms Cr?

grigory [225]

Answer:

0.125 mole

Explanation:

From Avogadro's hypothesis, we discovered that 1 mole of any substance contains 6.02x10^23 atoms.

The statement above suggests that 1 mole of chromium contains 6.02x10^23 atoms.

Now, if 1mole of of chromium contains 6.02x10^23 atoms,

Then Xmol of chromium contains 7.52x10^22 atoms i.e

Xmol of chromium = 7.52x10^22/6.02x10^23

Xmol of chromium = 0.125 mole

Therefore, 0.125 mole of chromium contains 7.52x10^22 atoms

8 0

2 years ago

The Lewis structure for CO2 has a central The Lewis structure for C O 2 has a central blank atom attached to blank atoms.

kirza4 [7]

Answer:

See the explanation

Explanation:

1) The Lewis structure for $CO_2$ has a central Carbon atom attached to Oxygen atoms.

In the $CO_2$ we will have a structure: O=C=O the central atom "carbon" we will have 2 sigma bonds and 2 pi bonds, therefore, we have an Sp hybridization. For O we have 1 pi and 1 sigma bond, therefore, we have an Sp2 hybridization.

2) These atoms are held together by double bonds.

Again in the structure of $CO_2$ : O=C=O we only have double bonds.

3. Carbon dioxide has a Carbon dioxide has a Linear electron geometry.

Due to the double bonds we have to have a linear structure because in this geometry the atoms will be further apart from each other.

4. The carbon atom is Sp hybridized.

We will have for carbon 2 pi bonds, so we will have an Sp hybridization.

5. Carbon dioxide has two Carbon dioxide has two C(p) - O(p) π bonds and two C(sp) - O(Sp2) σ bonds.

(See figures)

Figure 1: Carbon hybridization

Figure 2: Oxygen hybridization

6 0

2 years ago

In a particular mass of kau(cn)2, there are 6.66 × 1020 atoms of gold. What is the total number of atoms in this sample?

Vinvika [58]

Total number of atoms in the sample is the sum of number of atoms of all the elements present in the sample.

Number of gold, $Au$ atoms in $KAu(CN)_2$ = $6.66\times 10^{20}$ atoms (given)

From the formula of compound that is $KAu(CN)_2$ it is clear that the number of potassium and gold are same whereas those of carbon and nitrogen are 2 times of them.

So, the number of atoms of each element is:

Number of potassium, $K$ atoms in $KAu(CN)_2$ = $6.66\times 10^{20}$ atoms

Number of carbon, $C$ atoms in $KAu(CN)_2$ = $2\times6.66\times 10^{20}$ atoms = $13.32\times 10^{20}$

Number of nitrogen, $N$ atoms in $KAu(CN)_2$ = $2\times6.66\times 10^{20}$ atoms = $13.32\times 10^{20}$

Total number of atoms in $KAu(CN)_2$ = Number of gold, $Au$ atoms+Number of potassium, $K$ atoms +Number of carbon, $C$ atoms + Number of nitrogen, $N$ atoms

Total number of atoms in $KAu(CN)_2$ = $6.66\times 10^{20}+6.66\times 10^{20}+13.32\times 10^{20}+13.32\times 10^{20}$

Total number of atoms in $KAu(CN)_2$ = $39.96\times 10^{20}$ atoms

Hence, the total number of atoms in $KAu(CN)_2$ is $3.996\times 10^{21}$ atoms.

7 0

2 years ago