CHM101A Anions Cationsand Ionic Reactions Severson PDF

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CHM 101A Anions, Cations, and Ionic Reactions Final Report Student Name

Erik Severson

Student ID

160930

Lesson

Anions, Cations, and Ionic Reactions

Institution

National University

Session

CHM 101A - 25511

Course

CHM 101A

Instructor

Mary Ann Dwyer

Test Your Knowledge 1. Label each element with the charge of the ion that it tends to form.

1

+2

3

+1

2

-2

4

+3

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2. Match each term with the best description.

Elements with similar chemical properties are found in a(n)

1

on

Group

the periodic table.

An element that is malleable and ductile is likely to be a(n)

2

Metal

When an atom loses electrons, it forms a positively-charged particle called a(n) 3

Cation

4

Ion

.

is the term used for any charged particle.

Positive

Metals tend to form ions with a(n)

5

Anions are particles with a(n)

Negative

6

charge.

charge.

3. Label the components of the double displacement reaction.

1

Ionic Compounds

2

Cations and Anions

3

Solid and Salt

Exploration 1. A cation is an element that _____ one or more electrons to form _____ ions. loses; positive loses; negative gains; positive gains; negative

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.

2. Group 2 on the periodic table of elements includes alkaline earth metals that readily form ions with a _____ charge. +1 +2 +4 -1 -2 -4

3. A hallmark of many ionic compounds is their ability to dissolve in water through a process called _____. anion mixing cation mixing hydration humidification reactivation

4. Ionic compounds are chemical compounds in which the anion and cation are held together by strong electrostatic attractions in a lattice structure. True False

5. A double displacement reaction occurs when _____. two anions form an ionic bond the reactants, a salt and a solid, share ions the anions and cations of ionic compounds switch places hydration replaces two cations

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6. In an ionic reaction, spectator ions are not involved in the production of _____. a precipitate a gas water All of the above

7. Confirmation tests are _____. qualitative tests to identify anions and cations in unknowns quantitative tests to identify anions and cations in unknowns always performed with hydrochloric acid

Exercise 1 1. What was the identity of the anion in Unknown #103? Explain how you used the observations recorded in Data Table 1 to reach this conclusion. The identity of the anion in Unknown #103 is carbonate. The reaction in data table 1 of both 103 and carbonate were identical with each other.

2. What was the identity of the anion in Unknown #104? Explain how you used the observations recorded in Data Table 1 to reach this conclusion. Identity of anion in #104 is sulfide. The data recorded in data table 1 for #104 matched the data for sulfide, indicating the same reaction occurred and sulfide was the chemical in common.

3. Write the chemical equation for the ionic reaction between Na2 S and AgNO3 . AgNO3 + Na2S = Ag2S + NaNO3

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4. Write the chemical equation for ionic reaction between NaBr and AgNO3 . AGNO3 + NABR = NANO3 + AGBR

Date Table 1: Anion Confirmation Tests

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Chemical

Anion

NaBr

Bromide

Na2 CO3

Carbonate

NaCl

Chloride

NaI

Iodide

Na2 SO4

Sulfate

Na2 S

Sulfide

Unknown #103

CO2 3

Unknown #104

S2

Chemical

Observations: Addition of AgNO3

NaBr

White and cloudy

Na2 CO3

Outside was white and cloudy and inside was clear

NaCl

Clear on top and white/cloudy on bottom

NaI

Very dark in the middle, with a cloudy/lighter color around it

Na2 SO4

Clear

Na2 S

Brown in the middle and began to seperate

Unknown #103

Small white/cloudy particles

Unknown #104

Brown in the middle and clear around the outsides

Chemical

Observations: Addition of HCl

NaBr

Still white and cloudy

Na2 CO3

White and cloudy, but bubbled up

NaCl

Still clear on top and white/cloudy on bottom

NaI

It began to seperate

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Na2 SO4

Turned white and cloudy

Na2 S

The brown separates further from the clear

Unknown #103

Bubbles emerge and it became white and cloudy

Unknown #104

Brown seperated and vanished

Exercise 2 1. What was the identity of the cation in Unknown #105? Explain how you used the observations recorded in Data Table 2 to reach this conclusion. The identity of the cation in #105 is copper. Due to the fact during the flame observations it burned the same color as the unknown substance.

2. If you were asked to confirm the identity of an unknown chemical such as lithium sulfide (Li 2 S), describe the tests that you would use to confirm the identity. Use your results in both Exercise 1 and Exercise 2 to describe the observations in both the cation and anion tests that would allow the unknown to be confirmed as lithium sulfide. I personally would follow the procedure used for this lab and place the unknown chemical into a well and then add AgNO3 and HCl. Then I would record my observations to find the anion. Then after that perform the flame cation test. The data taken from both of these tests should be able to tell me the identity of the unknown chemical.

Data Table 2: Cation Flame Tests

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Chemical

Cation

Observations: Flame Test

KI

Potassium

Light Pink

CaCl 2

Calcium

Red

LiOH

Lithium

Fuchsia

NaCl

Sodium

Orange

Cu(NO3)2

Copper

Teal

Unknown #105

Copper

Teal

Unknown #106 Unknown #107

Data Table 3: Complete Chemical Identification

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Chemical

Cation

Unknown #105

Copper

Unknown #106

Potassium

Unknown #107

Calcium

Chemical

Anion Test Observations

Unknown #105

No Change

Unknown #106

Dark in the middle and fades out fast

Unknown #107

Turns white/cloudy

Chemical

Anion

Unknown #105

(CO2)3

Unknown #106

I

Unknown #107

Cl

Chemical

Complete Chemical Name and Formula

Unknown #105

Copper(II) Nitrate Cu(NO3)2

Unknown #106

Potassium Iodide, Kl

Unknown #107

Calcium Chloride, CaCL2

Competency Review 1. When an element _____ one or more electrons, it becomes a negatively charged particle called a(n) _____. gains; anion gains; cation loses; anion loses; cation

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2. A bromide ion has a charge of _____. -2 -1 0 +1 +2

3. Group 1 of the periodic table of elements includes alkali metals that readily form ions with a _____ charge. -2 -1 0 +1 +2

4. A double displacement reaction can generate products, including a precipitate, a gas, or a salt and water. True False

5. In an ionic compound, the _____ is listed first, followed by the _____. cation; anion anion; cation salt; water water; salt

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6. In the compound NaCl, chlorine is the _____. anion cation spectator ion

7. When NaI and AgNO3 are mixed, _____. no reaction occurs a reaction occurs, as indicated by a precipitate

8. How might a scientist identify the anion of an unknown substance? Perform flame tests. Perform a series of reactions with known substances and compare these to reactions with the unknown. Write formulas for chemical compounds and label the charges of the anions and cations.

9. How might a scientist identify the cation of an unknown substance? Perform flame tests. Perform a series of reactions with known substances and compare these to reactions with the unknown. Write formulas for chemical compounds and label the charges of the anions and cations.

10. An effective way to identify the anion and cation of an unknown ionic compound is to perfom confirmation tests using both flame tests and known reactions. True False

Extension Questions

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1. A solution containing an ionic compound is subjected to the anion and cation confirmation tests performed in this experiment, providing the following results: Addition of silver nitrate: a bright yellow precipitate formed. Flame test: a purple color was observed. Identify the ionic compound and write the chemical reaction that occurs when the ionic compound interacts with the silver nitrate. Identify the spectator ions. The spectator ions in this are K+ and NO-3, since these ions do not involve any reaction.

It is given that a bright yellow precipitate is formed when the substances given reacts with silver nitrate. Silver nitrate reacts with anion iodide (I-) to form a yellow precipitate. In the flame test if we get a purple color then the cation MUST be Potassium (K+). If we combine the cation and anion we will get the compound as Potassium Iodide (KI)

K+ + I- + Ag+ + NO3- ---> KNO3 + AgI (S)

The Silver and Iodide ions combine to form a precipitate and POtassium and nitrate ions are acting as spectator ions, which do not involve reaction.

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