CHEM 14A Lecture Notes - Universal Indicator, Ph Meter, Logarithm

7 views1 pages

turquoisemoose666

7 Dec 2020

School

UCLA

Department

Chemistry and Biochemistry

Course

CHEM 14A

Professor

Dr.Laurence Lavelle

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Ph: the negative logarithm (to the base 10) of the hydronium ion activity. The negative sign in the definition of ph means that the higher the concentration of. The ph of a basic solution is greater than 7. The ph of a neutral solution is equal to 7. The ph of an acidic solution is less than 7. The range is 0 to 14, but values outside this range is possible. The approximate value of the ph of an aqueous solution can be determined very quickly by using a strip of universal indicator paper. Most precise measurements are made with a ph meter . To convert a ph value into a concentration of h3o+ ions, reverse the sign of the ph and then take its antilogarithm. To summarize, the ph scale is used to report the molar concentration of h3o1 ions: ph.

Related Questions

pH operates off of a ___________ scale.

The autoionization constant of water is abbreviated ________.

The molar concentration of hydronium in pure water at 25ÂºC has been measured to be ________.

The relationship between hydronium and hydroxide in any dilute aqueous solution is represented by _________.

The p in pH stands for _________.

The relationship between pH and pOH is ___________.

The pH value of a 1 M solution of strong acid would be _________.

Neutral pH is ________.

An indicator is typically a ____________ acid or base.

The pOH value of a 1 M solution of strong acid would be _________.

Choose the answer below:

A. Ka = [H3O+][OH-]

B. 1x10-14

C. Kw = [H3O+][OH-]

D. 14

E. - log

F. Ka

G. 1.0x10-7 M

H. Kw

I. log

J. 7

K. 0

L. strong

M. natural log

N. 14 = pH + pOH

O. weak

An aqueous solution of 0.080 M KCN is made. At equilibrium this solution will be?

Basic

Neutral

Acidic

Suppose you need to calculate the pH of an aqueous KCN solution. How many of these statements should you be thinking about in advance?

pH should be < 7

don't forget pH = 14 - pOH

pH should be > 7

The mass action equation will be set equal to Ka

I need an ICE table and a Kb or Kw/Ka

pH = -log[x]

-log[x] = pOH not pH

What reaction would you use in an ICE table to calculate the pH of a KCN solution? CN- + H2O â HCN + H3O+

CN- + H2O â HCN + OH-

H+ + OH- â H2O

KCN (s) â K+ + CN-

What is the pH of a 0.080 M KCN solution.

The Ka for HCN is 8.0Ã10-10

QUESTION 1

Which of the following substances is most acidic?

		Cowâs milk - pH 6.6
		Apple juice - pH 3.0
		Tomato juice - pH 4.5
		Distilled water - pH 7.0

2 points

QUESTION 2

A buffer is a substance that converts:

Alkaline solutions to neutral solutions.

Acidic solutions to alkaline solutions.

Strong bases or acids to weak bases or acids.

Acidic solutions to neutral solutions.

QUESTION 3

How does a solution of pH 7 compare to a solution of pH 10?

		pH 7 has more OH^- ions
		pH 7 is more basic
		pH 7 has a higher pH
		pH 7 has more H⁺ ions

2 points

QUESTION 4

According to the Arrhenius Theory of acids and bases, a base is:

A substance that decrease the amount of hydroxide ions present.

A substance that increases the amount of hydroxide ions present when it is dissolved in water.

A substance that increase the amount of hydrogen ions present.

A substance that increases the amount of hydrogen ions present when it is dissolved in water.

QUESTION 5

Which of the following are true regarding acid-base titrations?

		They are used to determine the concentration of an unknown acid or base.
		The acid or the base must be a standard solution with a known concentration
		The standard solution is titrated into the chemical with the unknown concentration.
		All of the above are true regarding acid-base titrations.

2 points

QUESTION 6

Which of the following is not an example of a neutralization reaction?

HCl + NaOH NaCl +H₂O

2 NaOH + H₂CO₃ Na₂CO₃ +2 H₂O

H₂SO₄ + 2 NH₄OH (NH₄)₂SO₄ + 2 H₂O

2 AgNO₃ + Zn 2Ag +Zn(NO₃)₂

QUESTION 7

Which acid base theory defines an acid as a proton donor and a base as a proton acceptor?

		Arrhenius Theory
		Bronsted-Lowery Theory
		Conjugate Pairs Theory
		Lewis Theory

2 points

QUESTION 8

The Arrhenius Theory states that acid-base reactions create a solution composed of a water and a salt. This is because mixing an acidic and basic solution together yields:

A neutral solution

A solution with a pH at or near 7

Both A and B are correct

QUESTION 9

Which of the following correctly defines a standard solution?

		A solution which always has the same molecular geometry.
		A solution in which the concentration is precisely known.
		A solution in which the volume is precisely known.
		A solution which always has different levels of solutes and solvents.

2 points

QUESTION 10

Acids naturally present in food are generally safe to eat because they are usually:

		Concentrated
		Dilute
		Weak
		Strong

None of the above are correct

CHEM 14A Lecture Notes - Universal Indicator, Ph Meter, Logarithm

Document Summary

Get access

Related textbook solutions

Chemistry: Structure and Properties

Basic Chemistry

Principles of Chemistry Molecular Approach

Chemistry: Structure and Properties

Principles of Chemistry Molecular Approach

Chemistry: A Molecular Approach

Chemistry: A Molecular Approach

Principles of Chemistry: A Molecular Approach

Chemistry: The Central Science

Related Documents

CHEM 14A Chapter Notes - Chapter 12: Acid Dissociation Constant, Hydronium, Ph Meter

CHEM 14A Lecture Notes - Lecture 14: Sodium Bicarbonate, Sodium Hydroxide, Gastric Acid

CHEM 14A Chapter Notes - Chapter J.1: Chemical Formula, Svante Arrhenius, Organic Acid

Related Questions