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
tamaranim1 [39]
3 years ago
6

What mass of solid sodium formate (of MW 68.01) must be added to 150 mL of 0.42 mol/L formic acid (HCOOH) to make a buffer solu-

tion having a pH of 3.74? Ka = 0.00018 for HCOOH.
Answer in units of g.
Chemistry
1 answer:
Sergio [31]3 years ago
4 0

Answer:

We need 4.28 grams of sodium formate

Explanation:

<u>Step 1:</u> Data given

MW of sodium formate = 68.01 g/mol

Volume of 0.42 mol/L formic acid = 150 mL = 0.150 L

pH = 3.74

Ka = 0.00018

<u>Step 2:</u> Calculate [base)

3.74 = -log(0.00018) + log [base]/[acid]

0 = log [base]/[acid]

0 = log [base] / 0.42

10^0 = 1 = [base]/0.42 M

[base] = 0.42 M

<u>Step 3:</u> Calculate moles of sodium formate:

Moles sodium formate = molarity * volume

Moles of sodium formate = 0.42 M * 0.150 L = 0.063 moles

<u>Step 4:</u> Calculate mass of sodium formate:

Mass sodium formate = moles sodium formate * Molar mass sodium formate

Mass sodium formate = 0.063 mol * 68.01 g/mol

Mass sodium formate = 4.28 grams

We need 4.28 grams of sodium formate

You might be interested in
What is the specific latent heat of a fussion for a substance that takes 550 kj to melt 14 kg at 262 k?
Lina20 [59]

The latent heat is correlated with energy as follows:

Q = mL

550 * 103 = 14 * 103 * L

L = 39.285 J /g

Thus, latent heat of the substance is 39.285 j /g

7 0
3 years ago
Need asap! Step-by-step pls: Determine the empirical formula: 32.37% Na, 22.58% S, 45.05% O​
Ludmilka [50]

1) divide each percentage by the relative atomic mass of the element

2) divide all results by the smallest number

3)multiply by a whole number to get the simplest whole number ratio (if necessary)

that is to say:

Na                                   S                            O

32.37÷23                 22.58÷32                45.05÷16

= 1.407                       = 0.7056               = 2.816       (to 4 significant figures)

the smallest number here is 0.7056 so:

1.407÷0.7056        0.7056÷0.7056       2.816÷0.7056

=1.99 approx.2                   = 1                   3.99 approx. 4

here there is no need to carry out step 3 as ratio obtained is already a simplest whole number  ratio

so empirical formula is: Na₂SO₄

8 0
3 years ago
Give examples of five polymers that are manufactured using technological processes​
matrenka [14]
Plastics, paints, rubber, foams, adhesives, sealants, varnishes and many more.
4 0
3 years ago
There are three isotopes of X element (X):
Nutka1998 [239]

Answer:

Average atomic mass = 17.5 amu.

Explanation:

Given data:

X-17 isotope = atomic mass17.2 amu, abundance:78.99%

X-18isotope =  atomic mass 18.1 amu, abundance 10.00%

X-19isotope = atomic mass:19.1 amu, abundance: 11.01%

Average atomic mass of X = ?

Solution:

Average atomic mass  = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) + (abundance of 3rd isotope × its atomic mass)  / 100

Average atomic mass  = (78.99×17.2)+(10.00×18.1) +(11.01+ 19.1) /100

Average atomic mass =  1358.628 + 181 +210.291 / 100

Average atomic mass  = 1749.919 / 100

Average atomic mass = 17.5 amu.

8 0
2 years ago
Determine all values of hh and k for which the system has no solution
solniwko [45]
Explain more so i could answer it!!
6 0
2 years ago
Other questions:
  • HClO4+P4O10=H3PO4+Cl2O7 how do you balance this?
    11·1 answer
  • Addition of dns at the end of the incubation period stopped the reaction by denaturing sucrase. explain why it is important to d
    15·2 answers
  • What kind of bonding is found in Fe2O3?​
    9·1 answer
  • A 1.0mol sample of which of the following compounds has the greatest mass?
    9·1 answer
  • 3. A scientific investigation typically begins when a scientist makes observations that lead to the formation of a (n) _________
    10·1 answer
  • For each event stated below, indicate how the concentration of each species in the chemical equation then change to reach equili
    6·1 answer
  • How many electrons does an aluminum ion have?<br> a. 10<br> b. 13<br> c. 14<br> d. 16
    12·2 answers
  • Determine the rate of a reaction that follows the rate law:
    13·2 answers
  • Thermal energy from the sun travels to earth as waves
    9·2 answers
  • Would the size of an item affect whether or not it is flammable?
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!