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2 years ago

Complete the sentence

Chemistry

2 answers:

solmaris [256]2 years ago

5 0

Answer:

Explanation:

physical change

erica [24]2 years ago

5 0

The answer is Physical change.

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I need help, plz help me with this problem

Svetlanka [38]

Answer:

It's b

Explanation:

I had the same exact question

5 0

1 year ago

At 25 °C, how many dissociated OH– ions are there in 1243 mL of an aqueous solution whose pH is 2.07?

coldgirl [10]

<u>Answer:</u> The number of $OH^-$ ions dissociated are $8.57\times 10^{11}$

<u>Explanation:</u>

We are given:

pH = 2.07

Calculating the value of pOH by using equation, we get:

$2.07+pOH=14\\\\pOH=14-2.07=11.93$

To calculate hydroxide ion concentration, we use the equation to calculate pOH of the solution, which is:

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

We are given:

pOH = 11.93

Putting values in above equation, we get:

$11.93=-\log[OH^-]$

$[OH^-]=10^{-11.93}=1.17\times 10^{-12}M$

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Molarity of solution = $1.17\times 10^{-12}M$

Volume of solution = 1243 mL = 1.243 L (Conversion factor: 1 L = 1000 mL)

Putting values in above equation, we get:

$1.17\times 10^{-12}M=\frac{\text{Moles of }OH^-}{1.243L}\\\\\text{Moles of }OH^-=(1.17\times 10^{-12}mol/L\times 1.243L)=1.424\times 10^{-12}mol$

According to mole concept:

1 mole of a compound contains $6.022\times 10^{23}$ number of particles

So, $1.424\times 10^{-12}mol$ number of $OH^-$ will contain = $(1.424\times 10^{-12}\times 6.022\times 10^{23})=8.57\times 10^{11}$ number of ions

Hence, the number of $OH^-$ ions dissociated are $8.57\times 10^{11}$

3 0

2 years ago

The volume of a gas is reduced from 4 L to 0.5 L while the temperature is held constant. How does the gas pressure change?

liberstina [14]

Answer:

It increases by a factor of eight

Explanation:

When temperature is held constant, gas pressure changes according the volume, in undirectly proportion.

Volume increases → Pressure decreases

Volume decreases → Pressure increases

As volume gas, was reducted from 4L to 0.5L, it was reduced by 1/8, so the pressure gas was increased by a factor of eight.

5 0

2 years ago

The bonds between hydrogen and oxygen in a water molecule are classified as(1) polar covalent

klemol [59]

(1) Ploar covalent. is the answer.

6 0

2 years ago

Please help.

Anna35 [415]

Answer:

9429.9

Explanation:

periodt

4 0

2 years ago