The Periodic Table of Elements is a table that scientists use to show the elements (atoms) that are found in specific molecules. Each rectangle box in the table represents a different element.
The top number is the atomic or proton number and the bottom number is the relative atomic mass (which used to be called the ‘atomic weight'.)
Each element has an atomic number that is listed at the top of each box. The letter or letters that are listed in each box are the element's symbol.
For example, the first element listed in the table below is H (Hydrogen) with atomic number 1. The final part listed is the atomic mass or weight. For H (Hydrogen), the atomic mass is 1.008. If we rounded 1.008 to the nearest hundredth it would be 1.01.
Scientists or biotechnicians often need to use the Periodic Table of Elements to calculate molecular weight. Molecular weight is the total weight of all the elements in a molecule. A molecule is often made of many elements.
For example, the amu (atomic mass units) of the NaCl molecule is 58.4 amu. This is found by adding the atomic mass of each element in the NaCl molecule. Na weighs 23 (rounded 22.99 to 23) amu and Cl weighs 35.5 amu (rounded 35.45 to 35.5). The total is found by adding the atomic weight of both elements together: 23 + 35.5 = 58.5 amu.
Make Solutions:
One of the most important skills that an employee of a biotechnology laboratory must learn is how to prepare solutions. A solution is a combination of two or more materials. One of the materials must be a solute, which means it is being dissolved or broken up in a solvent. A solvent is the substance that the solute dissolves
For example, when you dissolve salt into water, the salt is the solute and the water is the solvent. Most molecules dissolve in water easily, but some are not easily dissolved in water.
If a solute is solid, it is measured on a scale or balance. A balance or scale measures the mass (weight) in grams (g) of the material. Some laboratories will measure in milligrams (mg) when doing research. Other labs who are in production of a solution will measure in kilograms (kg) because they are making large quantities of the same solution
The amount of solution that a lab technician needs to make determines the amount of solute that needs to be added to a solvent. A concentration is the proportion of solute to solvent. Concentrated solutions are common and most people are familiar with them
For example, laundry detergent can be bought in a concentrated solution. This means that less detergent needs to be measured out for each load of laundry because the solution is more concentrated.
Concentrated laundry detergent has a higher ratio of molecules to solvent than what is present in diluted, normal laundry detergent. Another advantage to using concentrated laundry detergent is that it comes in a smaller container than the regular version.
The concentration of a solution can be measured in a variety of ways. The three most common ways to measure the concentration is percentage of mass/volume, mass/volume in grams, and molarity.
Molarity is the method of measuring a concentration that will be focused on. Molarity is the measurement of concentration in a solution that signifies the number of moles of a solute in a liter of solution. One mole is equal to the molecular weight in grams of a substance. As in the previous exercise, molecular weight is found through adding the atomic mass of each element through the Periodic Table of Elements
For example, one mole of NaCl weighs 58.5 g. This is found by finding the atomic mass of Na and Cl on the Periodic Table. Na has an atomic mass of 23 (22.99 rounded to 23) and Cl has an atomic mass of 35.5 (35.45 rounded to 35.5).
Examples:
Now to solidify the meaning of a mole, how much do 2 moles of NaCl weigh? To find the answer, add the atomic mass of each element .
23 amu (Na) + 35.5 (Cl) = 58.5 g x 2 moles = 117 g.
How much does .5 mole of NaCl weigh? The molecular weight of NaCl is 58.5 g.
To find the answer: .5 mole x 58.5 g = 29.25 g.
Another way to find the answer to this question is this: 58.5 g x 1/2 = 29.25 g
Each element has an atomic number that is listed at the top of each box. The letter or letters that are listed in each box are the element's symbol.
For example, the first element listed in the table below is H (Hydrogen) with atomic number 1. The final part listed is the atomic mass or weight. For H (Hydrogen), the atomic mass is 1.008. If we rounded 1.008 to the nearest hundredth it would be 1.01.
Scientists or biotechnicians often need to use the Periodic Table of Elements to calculate molecular weight. Molecular weight is the total weight of all the elements in a molecule. A molecule is often made of many elements.
For example, the amu (atomic mass units) of the NaCl molecule is 58.4 amu. This is found by adding the atomic mass of each element in the NaCl molecule. Na weighs 23 (rounded 22.99 to 23) amu and Cl weighs 35.5 amu (rounded 35.45 to 35.5). The total is found by adding the atomic weight of both elements together: 23 + 35.5 = 58.5 amu.
Make Solutions:
One of the most important skills that an employee of a biotechnology laboratory must learn is how to prepare solutions. A solution is a combination of two or more materials. One of the materials must be a solute, which means it is being dissolved or broken up in a solvent. A solvent is the substance that the solute dissolves
For example, when you dissolve salt into water, the salt is the solute and the water is the solvent. Most molecules dissolve in water easily, but some are not easily dissolved in water.
If a solute is solid, it is measured on a scale or balance. A balance or scale measures the mass (weight) in grams (g) of the material. Some laboratories will measure in milligrams (mg) when doing research. Other labs who are in production of a solution will measure in kilograms (kg) because they are making large quantities of the same solution
The amount of solution that a lab technician needs to make determines the amount of solute that needs to be added to a solvent. A concentration is the proportion of solute to solvent. Concentrated solutions are common and most people are familiar with them
For example, laundry detergent can be bought in a concentrated solution. This means that less detergent needs to be measured out for each load of laundry because the solution is more concentrated.
Concentrated laundry detergent has a higher ratio of molecules to solvent than what is present in diluted, normal laundry detergent. Another advantage to using concentrated laundry detergent is that it comes in a smaller container than the regular version.
The concentration of a solution can be measured in a variety of ways. The three most common ways to measure the concentration is percentage of mass/volume, mass/volume in grams, and molarity.
Molarity is the method of measuring a concentration that will be focused on. Molarity is the measurement of concentration in a solution that signifies the number of moles of a solute in a liter of solution. One mole is equal to the molecular weight in grams of a substance. As in the previous exercise, molecular weight is found through adding the atomic mass of each element through the Periodic Table of Elements
For example, one mole of NaCl weighs 58.5 g. This is found by finding the atomic mass of Na and Cl on the Periodic Table. Na has an atomic mass of 23 (22.99 rounded to 23) and Cl has an atomic mass of 35.5 (35.45 rounded to 35.5).
Examples:
Now to solidify the meaning of a mole, how much do 2 moles of NaCl weigh? To find the answer, add the atomic mass of each element .
23 amu (Na) + 35.5 (Cl) = 58.5 g x 2 moles = 117 g.
How much does .5 mole of NaCl weigh? The molecular weight of NaCl is 58.5 g.
To find the answer: .5 mole x 58.5 g = 29.25 g.
Another way to find the answer to this question is this: 58.5 g x 1/2 = 29.25 g
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