Select the correct answer.

Which coefficients will balance the following reaction:

valentina_108 [34]

Answer:

C ) 2, 1, 2

Explanation:

The given reaction is synthesis reaction in which lithium and bromine react to form lithium bromide.

Chemical equation:

Li + Br₂ → LiBr

Balanced chemical equation:

2Li + Br₂ → 2LiBr

Step 1:

Li + Br₂ → LiBr

left hand side Right hand side

Li = 1 Li = 1

Br = 2 Br = 1

Step 2:

Li + Br₂ → 2LiBr

left hand side Right hand side

Li = 1 Li = 2

Br = 2 Br = 2

Step 3:

2Li + Br₂ → 2LiBr

left hand side Right hand side

Li = 2 Li = 2

Br = 2 Br = 2

3 0

3 years ago

Concentrated hydrochloric acid, HCl, comes with an approximate molar concentration of 12.1 M. If you are instructed to prepare 3

Semmy [17]

Answer:

28.20 mL of the stock solution.

Explanation:

Data obtained from the question include the following:

Molarity of stock solution (M1) = 12.1 M

Volume of diluted solution (V2) = 350.0 mL

Molarity of diluted solution (M2) = 0.975 M

Volume of stock solution needed (V1) =..?

The volume of stock solution needed can be obtained by using the dilution formula as shown below:

M1V1 = M2V2

12.1 x V1 = 0.975 x 350

Divide both side by 12.1

V1 = (0.975 x 350)/12.1

V1 = 28.20 mL.

Therefore, 28.20 mL of the stock solution will be needed to prepare 350.0 mL of 0.975 M HCl solution.

6 0

3 years ago

In which example does entropy increase?

nikklg [1K]

Explanation:

Entropy -

In a system, the randomness is measured by the term entropy .

Randomness basically refers as a form of energy that can not be used for any work.

The change in entropy is given by amount heat per change in temperature.

<u>entropy increases as the randomness increase , </u>

and ,

<u>entropy decrease as the randomness decreases . </u>

I. A piece of fruit freezes in liquid nitrogen.

randomness decreases , and so entropy decrease .

II. Librarians put library books back onto shelves at the end of the day.

randomness decreases , and so entropy decrease .

III. Liquid nitrogen boils in a beaker at room temperature.

change in state from less random liquid to gas , randomness increases , hence entropy increases

IV. Dry ice sublimes .

change in state from less random solid to gas , randomness increases , hence entropy increases .

V. A balloon collapses as its contents cool in liquid nitrogen .

cooling process , reduces the randomness , hence , entropy decreases .

5 0

4 years ago

The following compound has been found effective in treating pain and inflammation (J. Med Chem. 2007, 4222). Which sequence corr

love history [14]

<h3><u>Full Question:</u></h3>

The following compound has been found effective in treating pain and inflammation (J. Med. Chem. 2007, 4222). Which sequence correctly ranks each carbonyl group in order of increasing reactivity toward nucleophilic addition?

A) 1 < 2 < 3

B) 2 < 3 < 1

C) 3 < 1 < 2

D) 1 < 3 < 2

<h3><u>Answer: </u></h3>

The rate of nucleophilic attack of carbonyl compounds is 2<3 <1.

Option B

<h3><u>Explanation. </u></h3>

Nucleophilic attack is explained as the attack of an electron rich radical to a carbonyl compound like aldehyde or a ketone. A nucleophile has a high electron density, so it searches for a electropositive atom where it can donate a portion of its electron density and become stable.

A carbonyl compound is a $sp^2$ hybridized carbon atom with a double bonded oxygen atom in it. The oxygen atom pulls a huge portion of electron density from carbon being very electropositive.

In a ketone, there are two factors that make it less likely to undergo a nucleophilic attack than aldehyde. Firstly, the steric hindrance of two carbon groups being attached with the carbonyl carbon makes it harder for the nucleophile to approach. Secondly, the electron push by the carbon groups attached makes the carbonyl carbon a bit less electropositive than the aldehyde one. So aldehydes are more reactive towards a nucleophilic addition reaction.

7 0

3 years ago

Which of these statements best describes physical properties?

balu736 [363]

The correct answer would be D: Physical properties can be observed without changing the identity of a substance

5 0

2 years ago