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3 years ago

An organic chemistry student is experimentally determining the

Chemistry

1 answer:

MakcuM [25]3 years ago

4 0

Answer:

85.6 °C

Explanation:

Precision in scientific measurements refers to how close together the results of a repeated scientific measurement is. In this particular case where the melting point of fluorenone is being determined, precision refers to how close together the values from repeated measurements of the melting point of fluorenone is.

If we look at the values, the only one that is not close to others is 85.6 °C. Hence, if we remove this particular value, the data can be regarded as being precise.

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A buffer solution contains a weak acid, HA , and its conjugate base, A − . The buffer solution has a pH of 5.76 , and the weak a

ludmilkaskok [199]

Answer:

The relationship is expressed as follows: $K_{a} = \frac{[H+][A-]}{[HA]}$

Explanation:

Most acidic substances are weak acids and are therefore only partially ionized in acqeous solution. We cab use the equilibrium constant for the ionization of acid to express the extent to which the weak acid ionizes. If we represent a general weak acid as HA, we can write the equation for its ionization reaction like this:

$K_{a} = \frac{[H+][A-]}{[HA]}$

To calculate the pH of a weak acid, we use the equilibrium concentration of the reacted species and product.

Take for example:

HA → H + A⁻

where A id the conjugate base.

Knowing that x amount of acid reacts, we can solve like this:

HA → H + A⁻

H+ = antilog (pH)

thus, the pH of the acid is equals to H+ (initial) - H+ (equilibrium) ≈ H+ (initial)

4 0

4 years ago

Could someone please care to explain what the answer is

polet [3.4K]

Calculate the percentage composition of Ca(MnO4)2.

Firstly, we see how many atoms are there for each element in the formula.

Ca= 1 atom

Mn= 2 atoms

O= 8 atoms

Next, we are going to consult our periodic table for the atomic mass of each element.

Ca= 40

Mn= 55

O= 16

Then, we have to find the molar mass for the compound..

Here is the formula for calculating molar mass of an element:

Molar Mass= ( no. of atoms of the element × atomic mass of the element)

Now, we have to calculate the atomic mass of the compound. So using the molar mass formula for an element, we calculate the molar mass for each element then we sum up their molar masses to get the compounds molar mass.

Molar mass (Ca)= 1× 40

(Ca)= 40

Molar mass (Mn)=2×55

(Mn)= 110

Molar mass (O)= 8×16

(O)= 128

Now: Molar mass( compound)= (Ca)+(Mn)+(O)

= 40+ 110 128

= 278

This is everything we need to calculate our percentage composition for each element..

* The example says to find the percentage composition for Ca. So we only find for Ca, Which is already done using the formula and the answer is 14.39%.

To prove that your answer is correct, find the percentage composition for Mn and O as well. Then you add up their percentage compositions.

If you do and you get 100 as your answer, then your percentage compositions are correct.

Why don't you try finding the percentage composition for Mn and O, then add up all the three percentage compositions. If you 100 as their sum, then your percentage composition for each of the elements are correct.

6 0

3 years ago

Scientific knowledge can withstand the test of time because A. exceptions can be made regarding scientific laws. B. it is open t

Iteru [2.4K]

B. It is open to change as new evidence or data is discovered. If scientists discover new evidence, they must modify their theories to conform with the new data.

A. is incorrect. Scientific laws are so well established that there can be no exceptions.

C. is incorrect. A scientific theory is the collective judgement of scientists as to the best explanation for a phenomenon. A new observation may require modification of the theory.

D. is incorrect. Advancements in technology can provide new evidence that requires new explanations.

5 0

3 years ago

Read 2 more answers

Anna took a large, jagged rock down to the river near her home and placed it in the water where the water was moving very fast.

kupik [55]

Answer:

Explanation:

8 0

3 years ago

Why do.we need inactive ingredients?

mel-nik [20]

Answer:

Inactive ingredients are components of a drug product that do not increase or affect the therapeutic action of the active ingredient, which is usually the active drug. Inactive ingredients are added during the manufacturing process of pharmaceutical products such as tablets, capsules, suppositories, and injections

3 0

4 years ago