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2 years ago

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Potassium forms ions with a charge of +1 (K+). Iodine forms ions with a charge of -1. Selenium forms ions with a charge of -2 (S

e2-). Imagine that Potassium ions and Selenide ions combine to form Potassium Selenide. What numbers would be in the place of X and Y in: KXSeY

1 answer:

olga55 [171]2 years ago

5 0

It is given that the charge on potassium is +1 i.e. Potassium is a cation, K⁺ and the charge on selenium is given as -2, i.e. selenium is an anion, Se²⁻

The two ions are shown to combine to form a molecule: KXSeY where X and Y correspond to the proportions in which the two atoms combine.

Since the molecule is neutral, the positive and negative charges need to be balanced. This is possible only if 2 units of K⁺ combines with 1 unit of Se²⁻.

Therefore, the formula would be K₂Se

X = 2 and Y = 1

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Which of the following possess the greatest concentration of hydroxide ions?

jek_recluse [69]

Answer : The correct option is (d) a solution of 0.10 M NaOH

Explanation :

<u>(a) a solution of pH 3.0</u>

First we have to calculate the pOH.

$pH+pOH=14\\\\pOH=14-pH\\\\pOH=14-3.0=11$

Now we have to calculate the $OH^-$ concentration.

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

$11=-\log [OH^-]$

$[OH^-]=1.0\times 10^{-11}M$

Thus, the $OH^-$ concentration is, $1.0\times 10^{-11}M$

<u>(b) a solution of 0.10 M $NH_3$ </u>

As we know that 1 mole of $NH_3$ is a weak base. So, in a solution it will not dissociates completely.

So, the $OH^-$ concentration will be less than 0.10 M

<u>(c) a solution with a pOH of 12.</u>

We have to calculate the $OH^-$ concentration.

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

$12=-\log [OH^-]$

$[OH^-]=1.0\times 10^{-12}M$

Thus, the $OH^-$ concentration is, $1.0\times 10^{-12}M$

<u>(d) a solution of 0.10 M NaOH</u>

As we know that $NaOH$ is a strong base. So, it dissociates to give $Na^+$ ion and $OH^-$ ion.

So, 0.10 M of $NaOH$ in a solution dissociates to give 0.10 M of $Na^+$ ion and 0.10 M of $OH^-$ ion.

Thus, the $OH^-$ concentration is, 0.10 M

<u>(e) a $1\times 10^{-4}M$ solution of $HNO_2$ </u>

As we know that 1 mole of $HNO_2$ in a solution dissociates to give 1 mole of $H^+$ ion and 1 mole of $NO_2^-$ ion.

So, $1\times 10^{-4}M$ of $HNO_2$ in a solution dissociates to give $1\times 10^{-4}M$ of $H^+$ ion and $1\times 10^{-4}M$ of $NO_2^-$ ion.

The concentration of $H^+$ ion is $1\times 10^{-4}M$

First we have to calculate the pH.

$pH=-\log [H^+]$

$pH=-\log (1.0\times 10^{-4})$

$pH=4$

Now we have to calculate the pOH.

$pH+pOH=14\\\\pOH=14-pH\\\\pOH=14-4=10$

Now we have to calculate the $OH^-$ concentration.

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

$10=-\log [OH^-]$

$[OH^-]=1.0\times 10^{-10}M$

Thus, the $OH^-$ concentration is, $1.0\times 10^{-10}M$

From this we conclude that, a solution of 0.10 M NaOH possess the greatest concentration of hydroxide ions.

Hence, the correct option is (d)

3 0

3 years ago

What is the density of an object that has a mass of 28.1g and a volume of 96.2mL? Select the correct answer below: 0.292g/mL 270

kakasveta [241]

Answer:

0.292 g/mL.

Explanation:

From the question given above, the following data were obtained:

Mass of object = 28.1 g

Volume of object = 96.2 mL

Density of object =..?

Density of an object is simply defined as the mass of the object per unit volume of the object. Mathematically, it can be expressed as:

Density = mass / volume

With the above formula, we can obtain the density of the object as follow:

Mass of object = 28.1 g

Volume of object = 96.2 mL

Density of object =..?

Density = mass / volume

Density = 28.1 / 96.2

Density of object = 0.292 g/mL

Thus the density of the object is 0.292 g/mL

3 0

3 years ago

Match each type of learning to the correct definition.

andreev551 [17]

Answer:

conditioning

trial-and-error learning

insight learning

imprinting

the process of associating a stimulus with a good or bad outcome

the process of using prior knowledge to solve a problem

a bond to a individual or object shortly after birth or hatching

the process of performing a behavior more and more skillf

Explanation:

3 0

3 years ago

Which of these equations is balanced? a. H2SO4 + 2Al → Al2(SO4)3 + H2 b. 2KCl + Pb(NO3)2 → 2KNO3 + PbCl2

Lapatulllka [165]

The answer is B, you just check if it is the same on the left and right side

A:
Left side - Right side
2xH - 2xH
1xS - 3xS
4xO - 12xO
2xAl - 2xAl

Therefore A is not correct

B:
Left side - right side
2xK - 2xK
1xCl - 1xCl
1xPb - 1xPb
2xN - 2xN
6xO - 6xO

B is therefore correct as both sides add up

6 0

3 years ago

Read 2 more answers

Which indicator has to be used in order to get an emerald green color at a pH of 9?

Sphinxa [80]

I think it would be B maybe

8 0

2 years ago