1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
GaryK [48]
3 years ago
13

You are instructed to create 900. mL of a 0.29 M phosphate buffer with a pH of 7.8. You have phosphoric acid and the sodium salt

s NaH2PO4, Na2HPO4, and Na3PO4 available. (Enter all numerical answers to three significant figures.)
H3PO4(s) + H2O(l) <----> H3O+(aq) + H2PO4−(aq) Ka1 = 6.9 ✕ 10−3
H2PO4−(aq) + H2O(l) <----> H3O+(aq) + HPO42−(aq) Ka2 = 6.2 ✕ 10−8
HPO42−(aq) + H2O(l) <----> H3O+(aq) + PO43−(aq) Ka3 = 4.8 ✕ 10−13

Which of the available chemicals will you use for the acid component of your buffer?

A. H3PO4
B. NaH2PO4
C. Na2HPO4
D. Na3PO4

Which of the available chemicals will you use for the base component of your buffer?

A. H3PO4B. NaH2PO4C. Na2HPO4D. Na3PO4
Chemistry
1 answer:
Aleksandr [31]3 years ago
8 0

Answer:

B and C

Explanation:

When we have to do a buffer solution we always have to choose the reaction that has the <u>pKa closer to the desired pH value</u>. When we find the pKa values we will obtain:

pKa_1=-Log[6.9x10^-^3]=2.16

pKa_2=-Log[6.2x10^-^8]=7.20

pKa_3=-Log[4.8x10^-^13]=12.31

The closer value is pKa2 with a value of 7.2. Therefore we have to use the second reaction. In which  H_2PO_4^-^1 is the <u>acid</u> and HPO_4^-^2 is the <u>base</u>. Therefore the answer for the first question is B and the answer for the second question is C.

You might be interested in
Consider the following reversible reaction. 2H2O(g)&lt;—&gt;2H2(g)+O2(g) What is the equilibrium constant expression for the giv
masha68 [24]

The reaction: 2H2(g) + O2(g) → 2H2O(g), can be interpreted as: a. 2 moles of hydrogen gas reacts with 1 mole of oxygen gas to produce 2 moles of water.

7 0
3 years ago
Read 2 more answers
21. Apply Concepts Classify each reaction and balance the
adell [148]

The reactions are in order which includes combustion reaction, Hydration reaction, oxidation reaction, and displacement reaction.

a) A combustion reaction is a chemical reaction between a fuel and an oxidant where heat is released. The combustion reaction example is given below. It is a balanced chemical reaction.

2C₃H₆(g) + 9O₂(g) --------> 6CO₂(g) + 6H₂O(g)

b. A hydration reaction is a chemical reaction in which a molecule of water is added to another molecule. Here Aluminum oxide is added to water to form aluminum hydroxide.

4Al₂O3(s) + 6H₂O(l)------> 2Al(OH)3(s)

c. When a metal reacts with oxygen, the metal forms an oxide. Oxide is a compound of metal and oxygen. Here lithium metal reacts with oxygen to form lithium oxide.

2Li(s) + O₂(g)-----> Li₂O(s)

d. A displacement reaction is one in which a more reactive element displaces a less reactive element from a compound. Here Zinc is more reactive than silver, so silver was displaced to form Zinc Nitrate.

Zn(s) + 2AgNO₃(aq) -----> 2Ag(s) + Zn(NO₃)₂(aq)

To know more about reactions, click below:

brainly.com/question/11231920

         

#SPJ1

4 0
1 year ago
Three common gaseous compounds of nitrogen and oxygen of different elementary composition are known: (A) laughing gas containing
Ede4ka [16]

Answer:

Please find how these data prove the law of multiple proportions below

Explanation:

The law of multiple proportions was proposed by an English chemist called John Dalton. The law states that when two elements combine and to form more than one compound. The weights/masses of the second element in the two compounds, which combines with a fixed ratio of the first element, is in a simple whole number ratio.

In this question, Nitrogen is said to combine with oxygen to give three different compounds as follows:

A) laughing gas containing 63.65% nitrogen i.e. 0.6365g

This means that the mass of oxygen will be (1-0.6365) = 0.3635g

B) colorless gas containing 46.68% nitrogen i.e. 0.4668g

This means that the mass of oxygen will be 0.5332g

C) brown toxic gas containing 30.45% nitrogen i.e. 0.3045g

This means that the mass of oxygen will be 0.6955g

The ratios of oxygen in the three compounds is therefore:

0.3635: 0.5332: 0.6955

Divide this ratio by the smallest number (0.3635)

0.3635/0.3635 = 1

0.5332/0.3635 = 1.467

0.6955/0.3635 = 1.913

Multiply this ratio by 2, we have:

2: 2.9 : 3.8

Hence, the simple whole number ratio is 2:3:4.

This proves the law of multiple proportions that oxygen is in simple whole number ratio in the three different compounds.

4 0
3 years ago
How do you analyze chemical evidence?
Sever21 [200]
BIOLOGICAL & CHEMICAL EVIDENCE ANALYSIS
There are many different types of evidence that can be found at a crime scene. Physical evidence can be collected at the crime scene such as a murder weapon. Chemical evidence is any residue from liquids that such as poison and drugs. Biological evidence is when hair or skin from a persons body has been transferred to a physical surface and then be collected and tested.

This evidence can be used to find out what exactly happened at the scene of the crime, the history behind the crime and who was involved and could have committed it.

Our experts test and analyse many forms of evidence, which is vital when finding out the various incidences that happened at a crime scene.
3 0
3 years ago
Need help with Chemistry homework...
lesantik [10]

1. 3Fe + 202

2. 2Sr + 02

3. SN + 2NaOH

4. 2K + Br2

5. 2C8H18 + 25O2

6. 2Sb + 3I2

6 0
3 years ago
Other questions:
  • Consider the reaction between ozone and a metal cation, m2+, to form the metal oxide, mo2, and dioxygen: o3 + m2+(aq) + h2o(l) →
    8·2 answers
  • Explain why pure water has a very slight electrical conductivity.
    8·1 answer
  • 26)
    12·1 answer
  • Match the element with its number of valence electrons. Match Term Definition: Helium Aluminum Fluorine Sodium A) 1 B) 2 C) 3 D)
    9·2 answers
  • The Ka of a monoprotic weak acid is 0.00732. What is the percent ionization of a 0.123 M solution of this acid?
    12·1 answer
  • Which is a similarity between alcohol fermentation and aerobic respiration?<br>​
    9·2 answers
  • A person who studies genetics is called a geneticist. A geneticist would most likely be interested in learning about which of th
    6·2 answers
  • Nitrogen was heated from 17°C to 37°C. The original volume of nitrogen was 8.5 L. Find the new volume in liters assuming P and n
    9·1 answer
  • Be sure you have completed Table A by filling in the data. Write a caption for the table. Captions are 2-3 sentences describing
    9·2 answers
  • Hikers noticed that a sealed bag of potato chips puffs up when taken to the top of a mountain. suppose that at the valley floor
    5·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!