Hydrated Crystals

HASPI Medical Chemistry Lab Draft

Background/Introduction

Magnesiusm In The Body

Magnesium (Mg) is a mineral that is present in large amounts in the human body. It is a very important cofactor in more than 300 chemical reactions that keep the body working properly, including but not limited to:

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Hydrated Crystals, HASPI Medical Chemistry Lab DRAFT

  • Protein synthesis
  • Muscle contraction
  • Brain and nerve function
  • Blood glucose control
  • Blood pressure regulation
  • Energy production
  • Structural development of bones
  • DNA and RNA synthesis
  • Neutralizing stomach acid and peristalsis in the intestines

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Hydrated Crystals, HASPI Medical Chemistry Lab DRAFT

Table 1: Recommended Dietary Allowances for Magnesium
AGE / MALE / FEMALE / PREGNANCY / LACTATION
Birth – 6 months / 30 mg / 30 mg
7-12 months / 75 mg / 75 mg
1-3 years / 80 mg / 80 mg
4-8 years / 130 mg / 130 mg
9-13 years / 240 mg / 240 mg
14-18 years / 410 mg / 360 mg / 400 mg / 360 mg
19-30 years / 400 mg / 310 mg / 350 mg / 310 mg
31-50 years / 420 mg / 320 mg / 360 mg / 320 mg
51+ years / 420 mg / 320 mg

The average person’s body contains about 25 grams of magnesium, with 50-60% stored in the bones. People get magnesium through their diet and levels are largely controlled by the kidneys. On average, about 120mg of magnesium is excreted into urine each day.

Dietary Intake of Magnesium

Magnesium is widely distributed in plant and animal foods and beverages. Nuts, seed, whole grains, and vegetables like broccoli, squash, and spinach are good sources of magnesium. In general, foods that are high in fiber are high in magnesium. Other sources include dairy products, meats, chocolate, and coffee. Sometimes magnesium supplements are needed if magnesium levels are too low and are readily available in a variety of forms. Table 1 outlines the Federal Drug

Administration’s Recommended Dietary Allowances for magnesium by age and gender.

Magnesiusm and Health

Magnesium deficiency due to low dietary intake is uncommon but risks include habitually low intake or excessive losses of magnesium due to certain health conditions, chronic alcoholism, and/or the use of certain medications. Signs of magnesium deficiency can be as mild as a loss of appetite, nausea, vomiting, and fatigue. In more severe cases individuals may experience numbness and tingling, uncontrolled muscle contractions and cramps, seizures, personality changes, abnormal heart rhythms, and hypocalcaemia or hypokalemia (low levels of calcium and potassium due to a disruption in mineral homeostasis).

Research has shown that magnesium deficiencies might be involved in cardiovascular disease, type 2 diabetes, osteoporosis, and migraine headaches. While more well-designed, large trials are needed for more evidence, some studies suggest that magnesium supplementation can cause a small decrease in blood pressure among hypertension patients and reduce the risk of stroke. Likewise, diets with higher amounts of magnesium are associated with significantly lower risks of diabetes, osteoporosis, and chronic migraine headaches.

Too much magnesium is not a big health risk because properly functioning kidneys eliminate excess amounts in urine. However, high doses of magnesium from dietary supplements or medication can result in diarrhea and abdominal discomfort. Magnesium toxicity in the body usually only occurs when individuals consume upwards of 5,000 mg/day, which is more than ten times the FDA’s recommended daily allowance.

Magnesiusm in Medications and Treatments

Magnesium sulfate (MgSO4), also known as Epsom Salt, is one of many magnesium containing compounds that can be used for medical treatment. Magnesium sulfate can be prescribed for many reasons and can be bought at the local grocery store for a number of home remedies. If taken orally, magnesium sulfate holds on to water in the large intestine, preventing the body from reabsorbing fluids. This will cause the bowels to evacuate and can help someone who has constipation.

Magnesium also depresses the central nervous system, blocking nerve signals in the muscle. Soaking in a bathtub of warm water and Epsom Salt can help alleviate body aches and pains. If prescribed by a doctor, other magnesium containing compounds can help stop seizures by limiting muscle movements.

Magnesium can also be used for treating attention deficit-hyperactivity disorder (ADHD, anxiety, chronic fatigue, Lyme disease, fibromyalgia, and if applied topically it can be used to treat infected skin ulcers and speed up wound healing.

Hyrdrated Crystals

HASPI Medical Chemistry Lab # A

Scenario

A water molecule has a strong dipole, which means it has partial charges on either end. This is due to the asymmetric structure of water and the uneven electronegativity between hydrogen and water. Because of these partial charges, water is very attracted to ions.

This attraction is the reason that ionic substances dissolve and dissociate in water. The water surrounds the ions so that it can move around in the solution. In some cases, the water and the ions are so strongly attracted that when the water is evaporated from the solution some of the water molecules are trapped within the crystals that form. This happens in specific ratios for the chemicals that form hydrates.

In this lab we are going to work with Magnesium Sulfate Hydrate, a crystal made of MgSO4 and water. Your goal is to find the number of water molecules for each magnesium sulfate in the system.

Removing water from the system requires energy, which makes the removal of water an endothermic reaction. For many hydrates you can merely heat them for a period of time in order to force out the water. Once you have removed the water we call these an anhydrate, a term used for the compound once the water is removed. This also means that if you add water it is an exothermic process, where the energy is released as water is re-integrated into the crystalline structure.

Materials

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Hydrated Crystals, HASPI Medical Chemistry Lab DRAFT

Safety Goggles

Bunsen Burner

Ring Stand

Clay Triangle

Forceps

Crucible

Digital Scale

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Hydrated Crystals, HASPI Medical Chemistry Lab DRAFT

Procedure/Directions

Your lab team will be giving tasks, or directions, to perform on the left. Record your questions, observations, or required response to each task on the right.

Task / Response
1 / Obtain the necessary materials provided by your instructor.
Set up your Bunsen burner, stand, and clay triangle.
Be sure to keep your work area neat and organized. Wear safety goggles at all times at your work station and secure all long hair and loose clothing.
2 / Find the mass of your crucible and cover. Record your measurement. / Mass of crucible & cover:
______g
3 / Find the mass of your crucible, cover, and magnesium sulfate sample. Record your measurement.
Using your measurement in step 2, calculate the mass of just your magnesium sulfate hydrate sample. / Mass of crucible, cover & sample:
______g
Mass of hydrate sample:
______g
4 / Carefully place your crucible, cover and sample on the clay triangle and heat over a Bunsen burner for 10 minutes. Mark the time you start the heating process and calculate the time you need to remove your sample from the heat.
While heating your sample, you may work on another assignment given to you by your instructor. Be mindful of you Bunsen burner and work area. / Heat Start Time: ______
Heat End Time: ______
5 / Turn off your Bunsen burner and let your crucible, cover, and sample cool down for 20 minutes. Mark the time you turned off the Bunsen burner and the time it is safe to handle the crucible.
While cooling your sample, you may work on another assignment given to you by your instructor. Be mindful of you Bunsen burner and work area. / Cooling Start Time: ______
Cooling End Time: ______
6 / Once your crucible is cool enough to handle, find the mass of the crucible, cover and heated sample. Record your measurement.
Since you already know the mass of crucible and cover (step 2), calculate the mass of the heated, anhydrous sample. / Mass of crucible, cover & heated sample:
______g
Mass of crucible & cover:
______g
Mass of anhydrous sample:
______g
7 / Using the data you gathered in step 3 and step 6, calculate the amount of H2O in your sample. Remember to use the correct number of significant figures. / Mass of hydrate sample (Step 3):
______g
Mass of anhydrous sample (Step 6):
______g
Mass of H2O:
______g
8 / Calculate the moles of H2O present in your original MgSO4•XH2Ohydrate sample.
Remember to use the correct number of significant figures.
9 / Calculate the moles of anhydrous MgSO4 present in your sample.
Remember to use the correct number of significant figures.
10 / Derive an empirical formula (ratio between H2O and anhydrous MgSO4) for your original hydrated sample. Use the moles calculated in steps 8 and 9. This ratio becomes the coefficients in your compound. / ____MgSO4•____H2O
11 / Calculate the percent of water in a perfect sample of magnesium sulfate. Use the formula:
MgSO4• 7H2O
12 / Calculate the percent of water in the magnesium sulfate sample from your lab results. Use the formula you calculated in step 10 based on your mole ratio)
13 / Calculate your percent of error based on results of steps 11 and 12. Use your final% answers and plug in to % error formula

Analysis & Interpretation

Summarize your data into the following data table:

Measurements / Magnesium Sulfate
Crucible, cover & sample / g
Crucible and cover / g
Hydratedsample / g
Crucible, cover & heated sample / g
Crucible and cover / g
Anhydrous sample / g
H20 in sample / g
Moles of H20 in sample / mol
Moles of anhydroussample / mol
Empirical Formula / ____MgSO4 • ____ H2O

Connections & Applications

As per NGSS/CCSS incorporate extensions that allow teachers/students to choose outside activities recommended by the standards.

Goal of having a minimum of 3 options for every lab activity, but more can be included.May include:

  • Critical thinking question(s) requiring research
  • Medical case study related and/or reinforcing concept
  • Investigating a phenomena
  • Designing an experiment
  • Developing and/or building a model
  • Creating a multimedia or visual display to convey a concept
  • Conduct a research project (correctly citing text is crucial)
  • Constructing an oral or written presentation/argument (correctly citing text is crucial)
  • Collecting data and construction graphical representations
  • Assess accuracy and credibility of a scientific publication
  • Mathematical computations

Resources and References

List of references

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Hydrated Crystals, HASPI Medical Chemistry Lab DRAFT