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Yuri [45]
2 years ago
5

Please write a essay and pick one prompt and at least half a page long thank you!

Chemistry
1 answer:
MArishka [77]2 years ago
3 0
Changes in matter occur every day. There are two types of ways matter can be altered; physically and chemically. Physical changes do not change the composition of the matter while chemical changes occur when one or more substances turn into a completely new substance. Physical changes can be seen through an altering of the substances physical property. A substances physical property is observed and measured without changing the composition of the subject. Descriptive words that would help to identify a substance’s physical property include hard, soft, brittle, flexible, heavy, and light just to name a few. Let’s say you’re eating, throughout the day your stomach starts to growl that is what happens when your stomach is digesting your food. Digestion is an example of chemical change. Chemical change happens every day and more than half the time we don’t realize it whether it’s metal starting to rust, or our food starting to rot. Physical change can happen when your popsicle starts to melt, or your water starting starting to boil. These are examples of physical change.
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50.00 mL of 0.10 M HNO 2 (nitrous acid, K a = 4.5 × 10 −4) is titrated with a 0.10 M KOH solution. After 25.00 mL of the KOH sol
boyakko [2]

Answer:

b. 3.35

Explanation:

To calculate the pH of a solution containing both acid and its salt (produced as a result of titration) we need to use Henderson’s equation i.e.

pH = pKa + log ([salt]/[acid])     (Eq. 01)

Where  

pKa = -log(Ka)        (Eq. 02)

[salt] = Molar concentration of salt produced as a result of titration

[acid] = Molar concentration of acid left in the solution after titration

Let’s now calculate the molar concentration of HNO2 and KOH considering following chemical reaction:

HNO2 + KOH ⇆ H2O + KNO2    (Eq. 03)

This shows that 01 mole of HNO2 and 01 mole of KOH are required to produce 01 mole of KNO2 (salt). And if any one of them (HNO2 and KOH) is present in lower amount then that will be considered the limiting reactant and amount of salt produced will be in accordance to that reactant.

Moles of HNO2 in 50 mL of 0.01 M HNO2 solution = 50/1000x0.01 = 0.005 Moles

Moles of KOH in 25 mL of 0.01 M KOH solution = 25/1000x0.01 = 0.0025 Moles

As it can be seen that we have 0.0025 Moles of KOH therefore considering Eq. 03 we can see that 0.0025 Moles of KOH will react with only 0.0025 Moles of HNO2 and will produce 0.0025 Moles of KNO2.

Therefore

Amount of salt produced i.e [salt] = 0.0025 moles       (Eq. 04)

Amount of acid left in the solution [acid] = 0.005 - 0.0025 = 0.0025 moles (Eq.05)

Putting the values in (Eq. 01) from (Eq.02), (Eq. 04) and (Eq. 05) we will get the following expression:

pH= -log(4.5x10 -4) + log (0.0025/0.0025)

Solving above we get  

pH = 3.35

5 0
3 years ago
The names and chemical formulae of some chemical compounds are written in the first two columns of the table below. Each compoun
charle [14.2K]

Answer:

See below  

Explanation:

<u>          Name         </u>  <u>Formula </u>      <u>       Major species     </u> <u>  </u>        

Zinc iodide              ZnI₂            H₂O(ℓ),  I⁻(aq), Zn²⁺(aq),  

Nitrogen(I) oxide     N₂O           H₂O(ℓ),  N₂O(aq)

Sodium nitrite         NaNO₂      H₂O(ℓ),  Na⁺(aq), NO₂⁻(aq)

Glucose                   C₆H₁₂O₆    H₂O(ℓ),  C₆H₁₂O₆(aq)

Nickel(II) iodide       NiI₂            H₂O(ℓ),  I⁻(aq), Ni²⁺(aq)

  • Glucose and nitrogen(I) oxide are covalent compounds. They do not dissociate in solution.
  • The compounds containing metals are ionic. They produce ions in solution.
  • ZnI₂ and NiI₂ produce twice as many iodide ions as metal ions.
6 0
3 years ago
15. Which sample of argon gas has the same number of atoms as a 100.-milliliter sample of helium gas at 1.0 atm and 300. K? A) 5
OLga [1]

The sample of argon gas that has the same number of atoms as a 100 milliliter sample of helium gas at 1.0 atm and 300 is 100. mL at 1.0 atm and 300. K

The correct option is D.

<h3>What is the number of moles of gases in the given samples?</h3>

The number of moles of gases in each of the given samples of gas is found below using the ideal gas equation.

The ideal gas equation is: PV/RT = n

where;

  • P is pressure
  • V is volume
  • n is number of moles of gas
  • T is temperature of gas
  • R is molar gas constant = 0.082 atm.L/mol/K

Moles of gas in the given helium gas sample:

P = 1.0 atm, V = 100 mL or 0.1 L, T = 300 K

n =  1 * 0.1 / 0.082 * 300

n = 0.00406 moles

For the argon gas sample:

A. n =  1 * 0.05 / 0.082 * 300

n = 0.00203 moles

B. n =  0.5 * 0.05 / 0.082 * 300

n = 0.00102 moles

C. n =  0.5 * 0.1 / 0.082 * 300

n = 0.00203 moles

D. n =  1 * 0.1 / 0.082 * 300

n = 0.00406 moles

Learn more about ideal gas equation at: brainly.com/question/24236411

#SPJ1

8 0
1 year ago
HELP ASAP will give BRAINLIEST!
katovenus [111]

Answer:

Newton's 1st law,

Explanation:

5 0
3 years ago
Which is the correct Lewis structure for carbon monoxide?
LuckyWell [14K]
<span>The Lewis structure for CO has 10 valence electrons. For the CO Lewis structure you'll need a triple bond between the Carbon and Oxygen atoms in order to satisfy the octets of each atom while still using the 10 valence electrons available for the CO molecule.</span>
7 0
2 years ago
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