What is the older name for lanthanides and actinides?

Determine the pH of the following base solutions. (Assume that all solutions are at 25°C and the ion-product constant of water,

alexira [117]

Answer:

a) The pH of the solution is 12.13.

b) The pH of the solution is 12.17.

Explanation:

Ionic product of water = $K_w=1.01\times 10^-{14}$

$K_w=[H^+][OH^-]$

$1.01\times 10^-{14}=[H^+][OH^-]$

Taking negative logarithm on both sides:

$-\log[1.01\times 10^-{14}]=(-\log [H^+])+(-\log [OH^-])$

The pH is the negative logarithm of hydrogen ion concentration in solution.

The pOH is the negative logarithm of hydroxide ion concentration in solution.

$13.99=pH+pOH$

a) $1.39\times 10^{-2} M$ of NaOH.

Concentration of hydroxide ions:

$NaOH(aq)\rightarrow Na^+(aq)+OH^-(aq)$

So, $[OH^-]=1\times [NaOH]=1\times 1.39\times 10^{-2} M=1.39\times 10^{-2} M$

$pOH=-\log[1.39\times 10^{-2} M]=1.86$

$13.99=pH+pOH$

$13.99=pH+1.86$

pH=13.99-1.86=12.13

b) $0.0051 M$ of NaOH.

Concentration of hydroxide ions:

$Al(OH)_3(aq)\rightarrow Al^{3+}(aq)+3OH^-(aq)$

So, $[OH^-]=3\times [Al(OH)_3]=3\times 0.0051 M=0.0153 M$

$pOH=-\log[0.0153 M]=1.82$

$13.99=pH+pOH$

$13.99=pH+1.82$

pH=13.99-1.82=12.17

6 0

3 years ago

A chemist wants to find Kc for the following reaction at 709 K:2NH3(g) + 3 I2 (g) ----> 6HI(g) + N2(g)

irakobra [83]

Answer:

422455.41

Explanation:

Corrected from source,

Given that:-

$N2(g) + 3 H2(g)\rightarrow 2NH3(g) \ Kc_1 = 0.314$

The equilibrium constant for the reverse reaction will be the reciprocal of the initial reaction.

The value of equilibrium constant the reaction

$2NH3(g)\rightarrow N2(g) + 3 H2(g)$

is:

$Kc_{1}'=\frac{1}{0.314}$

$H2(g) + I2(g)\rightarrow 2 HI(g)\ Kc_2 = 51$

If the equation is multiplied by a factor of '3', the equilibrium constant of the reverse reaction will be the cube of the equilibrium constant of initial reaction.

The value of equilibrium constant the reaction

$3H2(g) + 3I2(g)\rightarrow 6 HI(g)$

is:

$Kc_{2}'={51}^3$

Adding both the reactions we get the final reaction. So, the equilibrium constants must be multiplied.

The value of equilibrium constant the reaction

$2NH3(g) + 3I2(g)\rightarrow 6 HI(g) + N2(g)$

is:

$Kc'=\frac{1}{0.314}\times {51}^3$ = 422455.41

3 0

3 years ago

What is the coordination number for atoms that pack within the diamond cubic crystal structure?.

irga5000 [103]

Coordination numbers are defined for the crystalline structures that tell about the numbers of atoms bonded to the central atom. The coordination number of a diamond is 4.

<h3>What is a coordination number?</h3>

A coordination number has been defining the number of the ions, atoms, and molecules that are bonded to the central atom of the crystalline compound or a complex.

The diamond has 8 carbon atoms in its one unit and its coordination number is 4 as its lattice type is face-centered cubic that has carbons at the corners and face center of the structure. One carbon contributes 1/8 hence and the faces center contributes 1/2.

Therefore, the diamond has a coordination number of 4.

Learn more about coordination numbers, here:

brainly.com/question/27289242

#SPJ4

6 0

1 year ago

During the war where did African-Americans receive the best treatment?

Sindrei [870]

Hope this helps. Sorry of it is long

Answer: military

African Americans received the best treatment in the military during war. Making up about 3/4 of the military, African American soldiers proved their efficiency and ability to serve the country, thus receiving more respect from society than if they were to work in more "common" jobs, for example in a factory. However, while they received the best treatment in the military during the war, African Americans still faced segregation within the units of the military, an important fact to note.

7 0

3 years ago

ELEMENTS ARE CLASSIFIED AS METALS, NONMETALS, AND METALLOIDS. USE THE PERIODIC TABLE AND IDENTIFY TWO OF EACH CLASSIFICATION.

alekssr [168]

Answer:

Elements are classified into- metals – Nonmetals- Metalloids – Noble gases. State which of A, B, C, D is a:

1) Metallic element

2) Non-metallic element

3) Metalloid

4) Noble gas.

A) Is non-malleable, non-ductile and a poor conductor of electricity

B) Has lustre, is malleable and ductile and a good conductor of electricity

C) Is unreactive and inert and present in traces in air

D) Shows properties of both metals and nonmetals

Explanation:

3 0

2 years ago