Preview

Determining the Number of Water Molecules in a Hydrate

Powerful Essays
Open Document
Open Document
723 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Determining the Number of Water Molecules in a Hydrate
Determining the Number of Water Molecules in a Hydrate

Results
Mass of empty beaker
55.11 g
Mass of beaker with hydrated copper (II) sulfate
58.13 g
Mass of hydrated copper (II) sulfate
3.02 g
Mass of beaker with dehydrated copper (II) sulfate (last weighing)
57.22 g
Mass of dehydrated copper (II) sulfate
2.18 g
Mass of dehydrated copper (II) sulfate (2nd weighing)
2.11 g

Questions
1. Calculate the value of “n”. Show your work. Include an example of ALL calculations involving solving for “n”.

3.02 g of hydrated copper sulfate is heated to drive off water. The dry sample has a mass of 2.11 g. What is the mole ratio between copper (II) sulfate, CuSO4, and water, H2O?

Mass of Hydrate 3.02 g
Mass of Dry Sample - 2.11g
Mass of Water 0.91 g

MM CuSO4= 63.55 + 32.07 + 4(16.00)= 159.62 g/mol
2.11 g CuSO4 (1 mol CuSO4 / 159.62 g) = 0.0132 mol CuSO4

MM H2O = 2(1.01) + 16.00= 18.02 g/mol
0.91 g H2O (1 mol H2O / 18.02 g) = 0.0505 mol H2O

0.0132 mol CuSO4 : 0.0505 mol H2O → divide through by 0.0132 to get CuSO4 ● 4 H2O n=4 In the formula for copper (II) sulfate there are five molecules of water per molecule of copper (II) sulfate. During the experiment there were some mistakes in the data because of human error. Scientists accidentally spilled the hydrated copper sulfate after the second measurement though it lost 0.07 g when it was only supposed to lose 0.02 g at maximum. This meant there was likely still more water in the sample. As is explained in question two below, when not all of the water is driven off there is a lower value of n. This may explain why the n value solved for in this experiment was four when the actual n value is five.

Each of the following errors affects the value of n. in each case, would the value of n increase or decrease? Explain.

2) Not all of the water is driven off.
If not all the water was driven off then the mass of the dehydrated compound would be more
Continue Reading
View Writing Issues

You May Also Find These Documents Helpful

  • Powerful Essays

    Gen Chem 2: Solubility Product Constant
    • 1473 Words
    • 6 Pages

    Gen Chem 2: Solubility Product Constant

    | [Solubility Product Constant] | Experiment 11 | | Molly McCabe | 4/18/2013 | | Data Tables: Part 1 and Part 2 Experimental Data: Standard | Calculated volume of copper sulfate in standards | Absorbance values | Blank | 0.0 mL | 0.0 | 1 | 1.25 mL | 0.094 | 2 | 3.75 mL | 0.065 | 3 | 2.50 mL | 0.099 | 4 | 3.50 mL | 0.129 | 5 | 5.00 mL | 0.187 | Collected Data | Test tube 1 | Test tube 2 | Test tube 3 | Test tube 4 | Test Tube 5 |…

    • 1473 Words
    • 6 Pages
    Powerful Essays
    Read More
  • Powerful Essays

    Percent Composition of Hydrates Essay Example
    • 971 Words
    • 4 Pages

    Percent Composition of Hydrates Essay Example

    4. Using the spatula add 3g of copper sulfate hydrate crystals to the crucible and determine the mass.…

    • 971 Words
    • 4 Pages
    Powerful Essays
    Read More
  • Satisfactory Essays

    How Many Moles Lab Report
    • 274 Words
    • 2 Pages

    How Many Moles Lab Report

    What is the mass of 0.75 moles of CuSO4 ? 9. How many atoms does 2.0 moles of He represent? 10. How many sodium ions are in 3.0 moles of NaCl?…

    • 274 Words
    • 2 Pages
    Satisfactory Essays
    Read More
  • Powerful Essays

    Chem Lab
    • 570 Words
    • 3 Pages

    Chem Lab

    2. Next, we measured our 80 ml of copper II sulfate and 20 ml of distilled water and combined them in a graduated cylinder.…

    • 570 Words
    • 3 Pages
    Powerful Essays
    Read More
  • Satisfactory Essays

    Lab of moles of iron and copper
    • 440 Words
    • 2 Pages

    Lab of moles of iron and copper

    3. a) 1.8 x 10-2 moles x 6.02x1023molecule x 1 atom = 1.1 x 1022 atoms of iron used…

    • 440 Words
    • 2 Pages
    Satisfactory Essays
    Read More
  • Satisfactory Essays

    Lab Report
    • 597 Words
    • 3 Pages

    Lab Report

    If one places a 1.0 M solution of glucose inside a bag and then places that bag into a beaker containing a 1.0 M solution of sucrose, the percent of mass lost in the bag is 10.5%. The solution in the bag is hypertonic while the solution in the beaker is hypertonic, which is why water moves from the bag to the beaker and the bag loses mass.…

    • 597 Words
    • 3 Pages
    Satisfactory Essays
    Read More
  • Good Essays

    Hydrate Lab
    • 500 Words
    • 2 Pages

    Hydrate Lab

    Hydrates are compound with a constant composition. Concepts of Law of Definite Proportions (hydrates remain in constant proportions) and Law of Conservation of Mass (this idea is used to determine the mass of water in the compound and, subsequently, the formula of the compound) are expressed in this experiment. In this experiment, the goal was to find the formula of copper sulfate pentahydrate by heating a sample of the blue compound in order to evaporate the water and receive the white-colored copper sulfate anhydrous. Using the mass of the original sample of copper sulfate pentahydrate subtracted by the new mass of the copper sulfate anhydrous, the mass of water lost is obtained and used to find the empirical formula. The expectation for…

    • 500 Words
    • 2 Pages
    Good Essays
    Read More
  • Good Essays

    Let's Get Started with Copper
    • 663 Words
    • 3 Pages

    Let's Get Started with Copper

    Calculate the moles of copper, this is the mass of copper (in g) divided by the atomic mass of copper, (63.5 g/mol)…

    • 663 Words
    • 3 Pages
    Good Essays
    Read More
  • Powerful Essays

    Hydrate Composition
    • 1334 Words
    • 6 Pages

    Hydrate Composition

    Hydrates are chemical compounds that contain discrete water molecules as part of their crystalline structure. Water is bound in most hydrates in definite, stoichiometric proportions, and the number of water molecules bound per metal ion is often characteristic of a particular metal ion. Many hydrated salts can be transformed to the anhydrous (without water) compound by application of heat. In this experiment, we determine the empirical formula of copper (II) sulfate – CuSO4.…

    • 1334 Words
    • 6 Pages
    Powerful Essays
    Read More
  • Good Essays

    Caloric Content of Food
    • 650 Words
    • 3 Pages

    Caloric Content of Food

    After organizing all the equipment necessary to perform the lab correctly and safety, I placed the empty beaker on to the scale and recorded the weight. Then I filled the beaker with 50 ml of water and measured it and recorded my results. I then place the beaker onto the burner stand. I took the temperature of the water before heating it up. I first started with the marshmallow. I put the marshmallow onto the fork and measured its weight. Then I lit the marshmallow on fire and place it under the beaker. After the flame was extinguished I measure the temperature of the water and recorded it. I then place the remains of the marshmallow and fork onto the scale and recorded my findings. I proceeded to do the same thing with a walnut and then with a potato trip and recording the results of each.…

    • 650 Words
    • 3 Pages
    Good Essays
    Read More
  • Good Essays

    Vanadium Niobium Tantalum
    • 2456 Words
    • 10 Pages

    Vanadium Niobium Tantalum

    Vanadium, pronounced veh-NAY-di-em, atomic symbol V, and atomic number associated with this transition metal is 23. The atomic weight of Vanadium is 50.942 grams per one mole. The electron configuration is 1S2 2S2 2P6 3S2 3P6 4S2 3D3 and the noble gas notation is [Ar] 4S2 3D3.…

    • 2456 Words
    • 10 Pages
    Good Essays
    Read More
  • Good Essays

    Hydrate Formula
    • 528 Words
    • 3 Pages

    Hydrate Formula

    This is supported by the experimental data collected from the experiment. From our data, it can be easily calculated that the mass of the lost water was .96g and the anhydrous salt left behind massed at 1.49g. Using this information it can be determine the moles of each substance (.96g/18.02g=.053 moles of water, and 1.49g/159.62=.00933 moles of anhydrous salt). This is possible to calculate due to the scientific understanding that the mass of an element in grams divided by its average atomic mass will calculate the moles it’s equivalent to. After calculating the moles of each, the ratio .053 moles of water to .00933 moles of anhydrous salt is formed. Then, by dividing the moles of water by the moles of anhydrous salt a ratio between the two will be formed. This is because of a scientific principle that when dividing the moles of one molecule by another will result in a proportion of moles of one element to 1 mole of the other. The calculation produces 5.6806 moles of water/1 mole of anhydrous salt and after rounding to the nearest whole number the ratio 6 moles of water to 1 mole of anhydrous salt forms. Last, when plugged into the chemical formula of the hydrate (copper (ii) sulfate), the result is 1CuSO46H2O, which is the formula of the…

    • 528 Words
    • 3 Pages
    Good Essays
    Read More
  • Better Essays

    Hydrate Lab
    • 970 Words
    • 4 Pages

    Hydrate Lab

    The lab in which we conducted last Tuesday was an analysis of a hydrate and what happens to it when it is heated. A hydrate is a crystalline compound which water molecules are chemically bound to it. In the lab, we were to analyze the difference in grams of the hydrate and the anhydrate. An anhydrate is the crystalline compound without the water molecules bound to it. During our lab, we were to heat up the crucible, the crucible with hydrate, and the crucible with an anhydrous and write down each weight, then repeat. Once we completed that task then we were to find the number of moles of water lost, the number of moles of anhydrous copper sulfate, percent comp of water in the hydrated copper sulfate, the mole ratio of moles of water and moles of anhydrous copper sulfate. Once this is all done, we found our percent error and compared it to the exact value.…

    • 970 Words
    • 4 Pages
    Better Essays
    Read More
  • Better Essays

    Experiment: Percent Water in a Hydrated Salt
    • 1013 Words
    • 5 Pages

    Experiment: Percent Water in a Hydrated Salt

    The purpose of this experiment was to determine the percent by mass in a hydrated salt, as well as to learn to handle laboratory apparatus without touching it. The hydrated salt, calcium carbonate, was heated with high temperature to release water molecules. Gravimetric analysis was used in this experiment to determine the percent by mass of water in a hydrated salt. The hypothesis of this experiment was accepted on the basis that the percent by mass of volatile water in the hydrated salt would be fewer than 30%. The percent by mass was determined by the mass of water loss devised by the mass of hydrated salt multiplied by total capacity (100%).…

    • 1013 Words
    • 5 Pages
    Better Essays
    Read More
  • Satisfactory Essays

    Chemistry
    • 641 Words
    • 3 Pages

    Chemistry

    When the Fe(s) was completely consumed, the precipitated Cu had a mass of 3.2 grams. Did the student’s result on this experiment verify the mole ratio of Fe(s) to Cu as predicted by the equation?…

    • 641 Words
    • 3 Pages
    Satisfactory Essays
    Read More

Related Topics