Log in
Chemistry
0
answers
0
watching
252
views
16 Nov 2019

Chem 1 Experiment 7: Empirical Formulas. Please show calculations and how you got the solution, thanks

Watch
0
answers
0
watching
252
views

For unlimited access to Homework Help, a Homework+ subscription is required.

discord banner image
Join us on Discord
Chemistry Study Group
Join now

Related textbook solutions

Basic Chemistry
5 Edition,
Timberlake
ISBN: 9780134138046
Principles of Chemistry Molecular Approach
4th Edition,
Tro
ISBN: 9780134112831
Chemistry: Structure and Properties
2nd Edition,
Tro
ISBN: 9780134293936
Principles of Chemistry Molecular Approach
3rd Edition, 2014
Tro
ISBN: 9780321971944
Chemistry: A Molecular Approach
3rd Edition,
Tro
ISBN: 9780321809247
Chemistry: A Molecular Approach
5th Edition,
Tro
ISBN: 9780134874371
Principles of Chemistry: A Molecular Approach
4th Edition,
Tro
ISBN: 9780134895741
Chemistry: The Central Science
14th Edition, 2017
Brown
ISBN: 9780134414232

Related questions

Decomposition of Malachite

Here is what Malachite is Made Out Of

Malachite is a famous and very popular semi-precious stone. Its banded light and dark green bands are one-of-a-kind, and give it a unique ornamental quality unlike that of any other stone. The light and dark green bands are so distinctive that malachite may be one of the most easily recognized minerals by the general public. Malachite is popular in jewelry, especially Native American southwestern jewelry. The stones inlayed in silver make a nice alternative to traditional turquoise jewelry.

Malachite is a form of copper carbonate with the molecular formula Cu2CO3(OH)2. When heated to around 200 �C, malachite decomposes into copper (II) oxide (CuO) and other products.

Reaction Stoichiometry

The Law of Conservation of Mass states that matter can neither be created nor destroyed. Therefore, the number of atoms of each element on the reactants side must be same as the number of atoms on the products side. This quantitative study of chemical reactions is called stoichiometry. The substances in a balanced reaction are related to each other by stoichiometric molar ratios. For example, magnesium reacts with hydrochloric acid in a 1:2 stoichiometric ratio in the balanced equation below.

Mg(s) + 2HCl(aq) -> MgCl2(aq) + H2(g)

The molar ratios can be used as conversion factors to find the amount (in moles) of one substance given the amount of another. For example, given the number of moles of HCl, the amount of MgCl2 can be determined as shown below.

nMgCl2=nHCl x (1mol MgCl2) / (2mol HCL)

The molar ratios are used to determine the amount in moles. However, the amount of reactant or product is often measured in grams. Mass can be converted to moles and vice versa as shown below.

n = m / (MM)

m = n x MM

where n is the number of moles, m is the mass of the product in g, and MM is its molar mass in g/mol.

To observe the Law of Conservation of Mass, you can perform different types of chemical reactions. For example, you can use a decomposition reaction to observe one compound being broken down into two or more elements or new compounds. For this reaction to take place, you must break existing bonds within the starting compound. Different sources of energy such as heat, light, or electricity may be used. Through a decomposition reaction, you can observe that the atoms in the original compound are not destroyed but are rearranged to form simpler substances, such as elements or compounds.

About This Lab

In this lab, you will test if the relationship between malachite and copper (II) oxide is stoichiometric. To do this, you will heat a known mass of malachite to produce copper (II) oxide. You will then compare the amount of copper (II) oxide obtained experimentally with the amount of copper (II) oxide expected from the balanced equation for the decomposition reaction.

1.Take a crucible from the Containers shelf and place it on the workbench.

2.Take a balance from the Instruments shelf and place it on the workbench.

3.Move the crucible onto the balance. Record the mass of the empty crucible to the nearest 0.001g in your Lab Notes.

4.Move the crucible onto the workbench.

5.Take copper (II) carbonate hydroxide from the Materials shelf and add 10 g to the crucible.

6.Move the crucible onto the balance and record the mass of the crucible containing copper (II) carbonate hydroxide in your Lab Notes.

7.Take a Bunsen burner from the Instruments shelf and place it on the workbench.

8.Move the crucible onto the Bunsen burner.

9.Double-click on the crucible to open its properties. Select Show Contents and click OK. This gives you a cut-away view of the crucible's contents.

10.Turn the Bunsen burner on to low flame by clicking the knob at the bottom once. Clicking multiple times will increase the intensity of the flame until it is turned off.

11.Watch the crucible until the malachite fully decomposes. You will see a distinct color change.

12.Move the crucible onto the workbench to cool.

13.Turn off your Bunsen burner.

14.Weigh the crucible with its contents and record the mass to the nearest 0.001 g in your Lab Notes.

Clear your station.

Lab Notes:

Numbers below refer to numbers in the above “About this Lab”

3. Empty crucible = 88 g

5. Added 10 g of Copper (II) carbonate hydroxide to crucible

6. Crucible with Copper (II) carbonate hydroxide = 98 g

11. to Black

14. after heating crucible with its contents = 95.195

Questions I have answered:

How many grams of malachite did you add to the crucible? 10g

How many grams of product were in the crucible after heating? 7.195

By how much did the mass of the crucible's contents change after heating? -2.805

The molar mass of malachite is 221.1 g/mol. How many moles of malachite were present before the reaction? 0.04523 mol

The product remaining in the crucible after heating is copper (II) oxide. The molar mass of copper (II) oxide is 79.55 g/mol. How many moles of copper (II) oxide were produced during the reaction?

0.0945 mol

Please answer the following:

Q1 a. Which of the following represents the balanced chemical equation for this reaction?

Cu2CO3(OH)2=2CuO+H2O

Cu2CO3(OH)2=CuO+CO2

Cu2CO3(OH)2=2CuO+H2O+CO2

Cu2CO3(OH)2=CuO+H2O+CO2

b. Based on the number of moles of malachite that you started with, how many grams of water were produced? The molar mass of water is 18.0153 g/mol. Choose the closest answer.

1.815 g 0.8148 g 1.630 g 1.982 g

c. Based on the number of moles of malachite that you started with, how many moles of CO2were produced? Choose the closest answer.

1.000 mol 0.04523 mol 0.9000 mol 0.09045 mol

d. Based on the number of moles of malachite that you started with, how many grams of CO2were produced? The molar mass of CO2 is 44.01 g/mol. Choose the closest answer.

1.991 g 0.4401 g 0.04523 g 3.981 g

Q2a. Based on the number of grams of CO2 and H2O produced during the reaction, does this compensate for the observed loss of mass?

A. No, because this violates the law of conservation of mass

B. yes, this compensates for the mass lost in the reaction

C. No, because more copper oxide was produced

D. No because mass is conserved

b. You observed that the products in the crucible weigh less than the reactants that you added. How is this possible?

A. Mass was lost due to experimental error

B. The Malachite absorbed CO2 from the air

C. CO2 and H2O were released as gases

D. Mass was converted to energy

c. What kind of a reaction took place upon heating?

A. decomposition

B. single displacement

C. synthesis

D. Double displacement

d. Baking soda is used as a leavening agent in baking. When heated, baking soda undergoes a decomposition reaction to form carbon dioxide. Given the data below, which of the following reactions occurs during baking? The molar mass of baking soda is 84.007 g/mol and the molar mass of carbon dioxide is 44.01 g/mol.

Mass of empty crucible (g) = 55.000

mass of crucible with baking soda (g) = 57.000

mass of crucible and contents after the reaction (g) =56.260

A. 2NaHCO3= 2Na+2CO2 +H2O

B. 2NaHCO3 = Na2O + 2CO2 +H2O

C. NaHCO3 = NaOH +CO2

D. 2NaHCO3 = Na2CO3 + CO2 +H2O

CHM111

Q1. Which of the following contains the MOST atoms? You shouldn't need to do a calculation here.

A) 10.0 g Ne

B) 10.0 g He

C) 10.0 g Ar

D) 10.0 g Kr

E) 10.0 g Mg

Q2. How many atoms are present in 0.23 moles of Calcium?

Q3. How many atoms are present in 5.6 mg of Silicon?

Q4. How many grams of iodine do 5.6 x 1025 atoms of iodine represent?

Q5. Balance the following Chemical Equations:

_____ CaC2(s) + _____H2O(l) ? _____ Ca(OH)2(aq) + _____ C2H2(g)

_____ P4O10 + _____ H2O? ______ H3PO4

___ C3H8O3 + ___ O2 ? ___ CO2 + ___ H2O

_____ C4H10(l) + _____ O2(g) ? _____ CO2(g) + _____ H2O(g)

___ Al + ___ N2 ? ___ Al2N3

___ NaN3 ? ___ Na + ___ N2

___ C3H5N3O9 ? ___ CO2 + ___ N2 + ___ H2O + ___ O2

Q6. Calculate the percent composition of each element in Al(NO3)3

Q7. A 65.0 g sample of a pure compound containing only Nickel, Oxygen and Carbon is found to contain 22.36 g Nickel and 18.27 g Carbon. What is the empirical formula of compound?

Q8. Determine the Empirical formula and Molecular formula of a compound that contains: 65.4% C, 9.15% H and 25.4% N by mass and has a molar mass of 220 g/mol.

Q9. Oxygen gas can be produced by the decomposition of KClO3

2KClO3 (s) ? 2 KCl + 3 O2 (g)

How many grams of O2 can be produced from 1.625 g of KClO3?

Q10. Consider the following balanced reaction: 2 Fe (s) + Al2O3 (s) ® 2 Al (s) + Fe2O3 (s)

If 6.25 moles of Fe react with 2.50 moles of Al2O3

Which reactant is the limiting reagent?

How many grams of Al are produced?

Q11. Consider the reaction for the manufacture of Aluminum sulfate:

2 AlCl3 (aq) + 3 H2SO4 (aq) ? Al2(SO4)3(aq) + 6 HCl (aq)

If 15.0 g of AlCl3was mixed with 25.0 g of H2SO4, which reactant is the limiting reagent?

Calculate the theoretical yield of Al2(SO4)3.

If only 18.63 g of Al2(SO4)3 was produced, what is the percent yield of Al2(SO4)3?

Q13. How many grams of Nickel (II) chloride are needed to prepare 100.0 ml of 0.125 M solution?

Q14. What volume of 0.125 M KMnO4 (aq) solution can be prepared from 12.623 g of KMnO4?

Having trouble with thse questions. Please answer all questions correctly. Will provide a thumbs up.

1.Which of these equations is the balanced reaction between nitrous acid solution and solidmagnesium hydroxide ?

A.2NH3(aq) + MgOH (s) Mg(NH4)2(aq) + 2 H2O(l)

B.2HNO2(aq) + Mg(OH)2(s) Mg(NO2)2(aq) + 2 H2O(l)

C.2HNO3(aq) + Mg(OH)2(s) Mg(NO3)2(aq) + 2 H2O(l)

D.2HNO2(aq) + MgOH (s) Mg(NO3)2(s) + 2H2O(l)

2.Balance the following chemical equation:

C3H7OH(l) + O2(g)CO2(g) + H2O(g)

a. C3H7OH(l) + 4 O2(g)3 CO2(g) + 4 H2O(g)

b.2 C3H7OH(l) + 9 O2(g)6 CO2(g) + 8 H2O(g)

c.C3H7OH(l) + 5 O2(g)3 CO2(g) + 4 H2O(g)

d.C3H7OH(l) + O2(g)CO2(g) + H2O(g)

3.Which species would be considered a spectator ion based on the following equation?

Ba2+ + 2NO3− + 2Na+ + SO42- → BaSO4(s) + 2NO3− + 2Na+

SO42-

2NO3−

Ba2+

BaSO4

4.Barium sulfate is often ingested to aid in the diagnosis of GI tract disorders. The equation for its production is Ba2+ + SO42- → BaSO4(s). What type of equation is this?

A full equation

A net ionic equation

A total ionic equation

An oxidation-reduction equation

5.Which species is being reduced in this reaction?

CuO(s) + H2(g) Cu(s) + H2O(g)

H2O

CuO

Cu

H2

6.Which of the following is an oxidizing agent?

H2

NH3

O2

H2O

7.The following chemical equation,

HC2H3O2(aq) + KOH(aq) KC2H3O2(aq) + H2O(l),

is an example of a(n) _______ reaction.

a.oxidation-reduction and acid-base

b.acid-base

c.precipitation

d.oxidation-reduction and precipitation

e.oxidation-reduction

8.What substance is oxidized in the following reaction?

4HCl + MnO2 → Cl2 + 2H2O + MnCl2

a.Mn in MnO2

b.O in MnO2

c.Cl in HCl

d.H in HCl

9.What is the reducing agent in the following reaction?

4HCl + MnO2 → Cl2 + 2H2O + MnCl2

Cl2

MnCl2

HCl

MnO2

10.All redox reactions involve oxygen.

True

False

11.The term formula weight can be used with respect to which of the following?

A.ionic compounds

B.covalent compounds

C.both a and b

D.neither a nor b

12.What is the molecular weight of ibuprofen, C13H18O2?

A.206.3 amu

B.377.7 amu

C.29.0 amu

D.289.4 amu

13.The mass of an atom of 12C is exactly 12 atomic mass units. Which of the following describes a mole of 12C atoms?

A.a sample which weighs exactly 12 atomic mass units

B.a sample which contains 6.02 × 1023 atoms of 12C

C.both a and b

D.neither a nor b

14.The mass of an atom of 12C is exactly 12 atomic mass units. Which of the following describes a mole of 12C atoms?

A.a sample which contains 6.02 × 1023 atoms of 12C

B.a sample which weighs exactly 12.011 grams

C.both a and b

D.neither a nor b

15.What is the molar mass of water, H2O?

A.18.02 g

B.18.02 amu

C.17.01 g

D.17.01 amu

16.What is the molar mass of glucose, C6H12O6?

A.180.2 amu

B.180.2 g

C.60.05 amu

D.60.05 g

17.In the reaction 2H2O → 2H2 + O2, 2.0 mol water will produce how many grams of O2?

32

64

16

36

18.In the reaction 2CH4 + O2 → 2CO + 4H2, how many molecules of CO will be produced by the complete reaction of 1.60 grams of CH4?

3.01 × 1022

2.00

12.0 × 1023

6.02 × 1022

19.Suppose 2.43 g of magnesium is reacted with 3.20 g of oxygen: 2Mg + O2 → 2MgO. How many grams of MgO will be produced?

1.27

4.03

5.63

8.06

20.Which of the following conversion factors would allow one to calculate the amount of PbI2produced from a given amount of NaI in the following unbalanced reaction?

Pb(NO3)2 + Nal → Pbl2 + NaNO3

a.

b.

c.

d.

21.The unbalanced equation for the reduction of copper(I) sulfide with oxygen is given below. What mass of copper is produced from the reduction of 7.50 g Cu2S?

Cu2S(s) + O2(g) Cu(s) + SO2(g)

18.8 g

5.99 g

1.50 g

9.39 g

2.99 g

22.How many grams of aluminum oxide are produced by the complete reaction of 19.8 g aluminum with excess oxygen?

10.5 g aluminum oxide

37.4 g aluminum oxide

49.9 g aluminum oxide

74.8 g aluminum oxide

23.If 5 grams of CO and 5 grams of O2 are combined according to the reaction, which is the limiting reagent?

2CO + O2 → 2CO2

O2

CO and O2

CO2

CO

24.In an industrial process, nitrogen is reacted with hydrogen to produce ammonia. The percent yield of this particular process is 26%. How much hydrogen is needed to produce 4.8 kg ammonia?

1.5 kg

7.0 kg

0.85 kg

3.3 kg

25.A percentage yield greater than 100% has been reported in a scientific paper you are assigned to read. What would be a reasonable explanation for this?

a. The product was measured more than once.

b. It must be a typographical error since yields can't exceed 100%.

c. A lack of training of the professor who published the study.

d. Small measurement errors could have caused this to occur.

26.In an industrial process, nitrogen is reacted with hydrogen to produce ammonia. The percent yield of this particular process is 24.8%. How much hydrogen is needed to produce 3.7 kg ammonia?

1.8 kg

1.2 kg

4.4 kg

12 kg

2.7 kg

27.The following reaction has a percent yield of 90.5%. How many grams of carbon dioxide are produced from 78.5 g calcium carbonate via this reaction?

2 HNO3(aq) + CaCO3(aq) Ca(NO3)2(aq) + H2O(l) + CO2(g)

34.5 g

21.6 g

38.1 g

31.2 g

28.When gas molecules dissolve in liquids to form a saturated system, the process is usually

exothermic.

endothermic.

independent of the nature of the liquid.

temperature independent.

29.The reaction below would be considered.

CaCO3 + heat → CaO + CO2

an exothermic combination.

an exothermic decomposition.

an endothermic combination.

an endothermic decomposition.

30.The combustion of one mole of propane, C3H8, releases 531 kcal. How much heat is released by the combustion of 1.20 moles of propane?

A.584 kcal

B.690 kcal

C.443 kcal

D.637 kcal

31.The combustion of one mole of propane, C3H8, releases 531 kcal. How much heat is released by the combustion of 4.40 g of propane?

A.531 kcal

B.5.31 × 104 kcal

C.53.1 kcal

D.5.31 × 103 kcal

32.Metabolism of one mole of glucose, C6H12O6, releases 670 kcal. How much heat is released by the combustion of 0.300 moles of glucose?

A.201 kcal

B.2.41 × 103 kcal

C.186 kcal

D.2.23 × 103 kcal

33.Metabolism of one mole of glucose, C6H12O6, releases 6.70 × 102 kcal. How much heat is released by the combustion of 50.0 g of glucose?

A.201 kcal

B.2.41 × 103 kcal

C.186 kcal

D.2.23 × 103 kcal

Weekly leaderboard

Home
Homework Help 3,900,000
Chemistry 830,000
Start filling in the gaps now
Log in