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2 years ago

Question 2(Multiple Choice Worth 4 points)

Chemistry

2 answers:

densk [106]2 years ago

6 0

Answer:

B. Construct a hypothesis

julsineya [31]2 years ago

6 0

Answer:

The correct answer will be option-C.

Explanation:

A scientific method is the systematic approach to understand and explain the natural events and phenomenon.

The method begins with making the observations which could lead to the formation of a scientific question. Background research is done based on which a predicted hypothesis is proposed which could be tested through the scientific experiments.

In the given question, student makes an observation on the basis of which he formulate a question. He do not review the background research on the question and directly formulates the hypothesis and follow other steps.

Since his method lacks the background research therefore, option-C is the correct answer.

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Compare and contrast the sun's rotation to that of the Earth

zimovet [89]

The Sun, like most other astronomical objects (planets, asteroids, galaxies, etc.), rotates on its axis. Unlike Earth and other solid objects, the entire Sun doesn't rotate at the same rate. ... The Sun's rotation rate decreases with increasing latitude, so that its rotation rate is slowest near its poles.

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3 years ago

What gas is produced when calcium metal is dropped in water

topjm [15]

Hydrogen gas

Calcium + Water. In the following demonstration, a chunk of calcium metal is dropped into a beaker of distilled water. After a second or so, the calcium metal begins to bubble vigorously as it reacts with the water, producing hydrogen gas, and a cloudy white precipitate of calcium hydroxide.

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2 years ago

Combination reactions always:

DerKrebs [107]

Answer:

require oxygen

Explanation:

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2 years ago

If 200 g of benzoyl peroxide are used with 38 Kg of PTFE monomer, calculate the expected molecular weight of the polymer if (i)

den301095 [7]

Explanation:

The molecular weight of benzoyl peroxide is 242.23 g/mol.

Therefore, number of moles present in 200 g of benzoyl peroxide are as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{200 g}{242.23 g/mol}$

= 0.825 mol

Molecular weight of PTFE is 100 g/mol.Hence, calculate the number of moles of PTFE in 38 kg as follows.

As 1 kg = 1000 g. So, 38 kg = 38000 g.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{38000 g}{100 g/mol}$

= 380 mol

As it is given that the initiator is 15% active. So, actual number of moles of benzoyl peroxide are as follows.

$0.15 \times 0.826$

= 0.124 mol

For combination, 1 mol of benzoyl peroxide produces 1 chain. Therefore, degree of polymerization will be calculated as follows.

DP = $\frac{380 mol}{0.124 mol}$

= 3065.33 mol

Average molecular weight of monomer is as follows.

$\frac{0.124}{0.124 + 380} \times MW_{benzoyl} + \frac{380}{0.124 + 380} \times MW_{PTFE}$

= 100.05 g/mol

Therefore, calculate the expected molecular weight of polymer as follows.

$3065.33 \times 100.05 g/mol$

= 306675.23 g/mol

Hence, for disproportion 1 mole benzoyl peroxide produces 2 chains.

DP = $\frac{2 \times 380}{0.124}$

= 6129.03

Therefore, calculate the expected polymer weight as follows.

$6129.03 \times 100.05$

= 613209.68 g/mol

Thus, we can conclude that the the expected polymer weight is 613209.68 g/mol.

6 0

3 years ago

How will you known that you have reached the equivalence point when titrating the NaOH solution with HCl?

Nitella [24]

Answer:

When the solution (with phenolphthalein) changes to colorless

Explanation:

When titrating with HCl is common to add phenolphthalein as an acid-base indicator.

Phenolphthalein is pink or fucsia when added into a basic solution. On the other hand when it is in acid solutions, is colorless.

So, when titrating, the NaOH solution will be initialy pink due to the phenolphthalein and when reaching the equivalence point, that color will fade out into colorless. This is how you know you hace reached the equivalent point.

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2 years ago