Name the following ionic compounds: Be3P2

What feature of single nucleotides provides the energy needed for polymerization when nucleic acids are formed?

lukranit [14]

When the phosphate groups of the single nucleotides combine to form the backbone of the nucleic acid, energy is released. This energy is used for polymerization.

4 0

3 years ago

Which of these do NOT show malleability a) Iron b) Sulfur c) Copper d) Aluminum

olganol [36]

Answer:Sulfur

Hope this helps!

Explanation:

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3 years ago

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A husband and a wife have two sons one boy has a straight thumb while the other has a bent thumb what causes the difference

Usimov [2.4K]

Answer:

Double/Triple joints

Explanation:

Double/Triple joints is when you can move a body part (thumb) farther than normal. (I think)

3 0

3 years ago

A sample of 9.27 g9.27 g of solid calcium hydroxide is added to 38.5 mL38.5 mL of 0.500 M0.500 M aqueous hydrochloric acid. Writ

navik [9.2K]

Answer: The excess reagent for the given chemical reaction is calcium hydroxide and the amount left after the completion of reaction is 0.115375 moles. The amount of calcium chloride formed in the reaction is 1.068 grams.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ....(1)

For calcium hydroxide:

Given mass of calcium hydroxide = 9.27 g

Molar mass of calcium hydroxide = 74.093 g/mol

Putting values in above equation, we get:

$\text{Moles of calcium hydroxide}=\frac{9.27g}{74.093g/mol}=0.125mol$

To calculate the moles of a solute, we use the equation:

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

We are given:

Volume of hydrochloric acid = 38.5mL = 0.0385 L (Conversion factor: 1 L = 1000 mL)

Molarity of the solution = 0.500 moles/ L

Putting values in above equation, we get:

$0.500mol/L=\frac{\text{Moles of hydrochloric acid}}{0.0385L}\\\\\text{Moles of hydrochloric acid}=0.01925mol$

For the given chemical equation:

$2HCl(aq.)+Ca(OH)_2(s)\rightarrow CaCl_2(s)+2H_2O(l)$

Here, the solid salt is calcium chloride.

By Stoichiometry of the reaction:

2 moles of hydrochloric acid reacts with 1 mole of calcium hydroxide.

So, 0.01925 moles of hydrochloric acid will react with = $\frac{1}{2}\times 0.01925=0.009625moles$ of calcium hydroxide.

As, given amount of calcium hydroxide is more than the required amount. So, it is considered as an excess reagent.

Thus, hydrochloric acid is considered as a limiting reagent because it limits the formation of product.

Amount of excess reagent (calcium hydroxide) left = 0.125 - 0.01925 = 0.115375 moles

By Stoichiometry of the reaction:

2 moles of hydrochloric acid produces 1 mole of calcium chloride.

So, 0.01925 moles of hydrochloric acid will produce = $\frac{1}{2}\times 0.01925=0.009625moles$ of calcium chloride.

Now, calculating the mass of calcium chloride from equation 1, we get:

Molar mass of calcium chloride = 110.98 g/mol

Moles of calcium chloride = 0.009625 moles

Putting values in equation 1, we get:

$0.009625mol=\frac{\text{Mass of calcium chloride}}{110.98g/mol}\\\\\text{Mass of calcium chloride}=1.068g$

Hence, the excess reagent for the given chemical reaction is calcium hydroxide and the amount left after the completion of reaction is 0.115375 moles. The amount of calcium chloride formed in the reaction is 1.068 grams.

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3 years ago

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12. Which compound can act as both a BrønstedLowry

oksian1 [2.3K]

1) The compound which can act as a Bronsted-Lowry acid and a Bronsted-Lowry base is definitely water - H2O. Remember that water is amphoteric which means it can either accept protons or donate them, so it is the most proper option among other represented. Here are examples of both base and acid with water : HCl+H20=H30+Cl ; NH3+H2O=NH4+OH

2) The acids in this equilibrium reaction CN– + H2O HCN + OH. Acid species always donate H+ to the species with which they react. In the second option you can see how H2O donates an H+ to CN-. If the reaction gets reversed we will obtain HCN that donates an H+ to OH that shows that it is an acid.

3) The products of self-ionization of water are OH⁻ and H₃O⁺. Self-ionization is an ionization reaction during which H2O deprotonates its hydrogen atoms to become a hydroxide ion -- OH−. After this process OH- protonates another water molecule forming H3O+.

4) The type of solution which is one with a pH of 8 is acidic. Here is a little table that can be a prompt for you if you ever come across such tasks - ph : 7 is neutral. pH lower than 7 are acidic, and pH higher than 7 basic ones.

5) The acid dissociation constant for an acid dissolved in water is equal to the equilibrium constant. I consider this option correct because we can obtan Kw only when dealing with Kb, and we can conclude that the hydrolysis constant of the conujugate base.

6) A 0.12 M solution of an acid that ionizes only slightly in solution would be termed dilute and weak. You can determine it depending on its concentration. Such value as 0.12M usually defined as a dilute solution of a weak acid due to the fact that acid represents its partial ionization which is a direct characteristic of a weak acid.

7) To solve this task we should appeal to Henry's law that says the solubility of a gaz is proportional to its partial pressure. And according to this we can understand that 202kPa is the half of 404kPa which means that the needed solubility must be divided by 2 7.5/2=3.75 g/L and that's all.

8) I think that the most important points which best show how the addition of a solute affects the boiling point, the freezing
point, and the vapor pressure of the solvent are : BOILING: additional attractive forces can only exist between solute and solvent and in order to boil they must be overcome for the solution;we should add KE to overcome the forces. FREEZING : to freeze we have to withdrawn KE as the solute particles are surrounded by solvent molecules. VAPOR : WHen solvent shells are being formed the solute particles reduces the number of solvent particles that have sufficient KE to vaporize.

9) $[H+][OH-]= Kw = 1.0 * 10^-14$
$[H+]= Kw/ [OH-]= 1.0x 10^-14 / 1 x 10^-11 =1 x 10^-3 mol/L 

pH = - log [H+]= - log 1 x 10^-3 = 3$
Since we got Ph of 3 in a result we can define solution as an acidic one, as I mentioned before.

10) Since the formula of the given acid is HA it undergoes like that : HA<=> H+ + A- .
ka = [H][A] / [HA].
Now we have only [H+] and to go further you need to write electroneutrality equation for the reaction :
[H+] = [OH-] + [A-] (since [H]>>>[OH]), then
[H+] = [A-]
Then mass balance equation :
Ct = 0.5M = [A-] + [HA]
[HA] = 0.5 - [A-] = 0.5 - [H+]
Finally here is what we have done and get :
$ka = [H]^2 / (0.5 - [H+]) 
$
$ka = 0.0001*0.0001/(0.5-0.0001) = 2.00x10^-8$

11) The main points that are common for acids : they form Hydrogen ions when dissloved in water, - Ex. Vinegar and Lemon, Ph >7, they have Increased hydrogen ions (H+). The facts about bases : they reduce the concentration of hydgoren ions in a solution which is opposite to asids,- Ex. Antiacid,and Ammonia ,Ph valuse above 7, they form hydrogen (OH-).
- The common points of both acids and bases : Hydrogen ions ,
both not neutral and water based.

5 0

3 years ago