Dimensional Analysis #5

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Transcript Dimensional Analysis #5

Chapter 5

Units

 Measures the drug in terms of action 

No symbol for units

Sample problems - Answers

 Express the unit dosage in numerals and symbols: 1.

A.

Three hundred and fifty thousand units.

350,000 units 2.

A.

Twenty-five hundred units.

25,000 units 3.

A.

Sixty units.

60 units

Percentage (%) measures

 Percentage means parts per hundred.

 No space between the # and the %  1% not 1 % 

The greater the percentage strength, the stronger the solution

or ointment.

Sample Question

 Which is stronger, a 3% solution or a 6% solution?

A.

3% B.

6%

Which of the following is the correct abbreviation for “units”?

A.

Un B.

U C.

UN D.

Ut E.

None of the above

Percentage (%) measures

 In solution, percent represents the number of grams of drug per 100 mL of solution.

 100 mL of a 1% solution will contain 1 g of drug

Sample Questions

 100 mL of a 1% solution will contain how many grams of drug?

 1 g  100 mL of a 2.5% solution will contain how many grams of drug?

 2.5 g  100 mL of a 10% solution will contain how many grams of drug?

 10 g

100 mL of a 5% solution will contain how many grams of drug?

A.1 g B. 5 g C. 10 g D.100 g E. None of the above

But what if it is not 100 mL Mrs. Keele?

Convert % to fraction

 To change percentage to fraction ÷ by 100  5% = 5 ÷ 100 = 0.05

What is the fraction of 7%

A.

70 B.

7 C.

0.7

D.

0.07

E.

0.007

What is the fraction of 60%

A.

60 B.

6 C.

0.6

D.

0.06

E.

None of the above

100 mL of a 5% solution will contain how many grams of drug?

100 𝑚𝐿 × 5% 5% = 5 ÷ 100 = 0.05

g/mL 100 × 0.05 = 5𝑔

250 mL of a 5% solution will contain how many grams of drug?

 250𝑚𝐿 × 5% =  5% = 5 ÷ 100 = 0.05

g/mL  250 × 0.05 = 12.5𝑔

325 mL of a 6% solution will contain how many grams of drug?

A.18.5 g B. 6 g C. 16.25 g D.19.5 g E. None of the above

120 mL of a 5.4% solution will contain how many grams of drug?

A.

6.45 g B.

64.5 g C.

645 g D.

None of the above E.

I’m so lost I have no idea!

260 mL of a 3% solution will contain how many grams of drug?

A.

0.78 g B.

7.8 g C.

78 g D.

780 g E.

None of the above

Milliequivalent (mEq) measures

 Number of grams of drug contained in 1 mL of a solution  Who cares?

 Not you  What do I need to know  -mEq = milliequivalent

Sample Questions:  Express the milliequivalent dosages in numbers and symbols: 1.

Fifteen milliequivalents A.

15 mEq 2.

Twenty-five milliequivalents 3.

A.

25 mEq Forty-two milliequivalents A.

42 mEq

Ratio Measures

 Parts of drug per parts of solution  1:500  1 part drug to 500 parts solution  1:20  1 part drug to 20 parts solution  A solution that is 1 part drug and 10 parts solution is written:  1:10

 If I take 1 bottle of alcohol & add it to 2 bottles of soda   1:2 ratio  How drunk would one glass of this spiked punch make you?

 If I take 1 bottle of alcohol & add it to 5 bottles of soda   1:5 ratio  How drunk would one glass of this spiked punch make you?

 Which would make you more drunk 1:2 or 1:5?

Ratio Measures

 The less solution a drug is dissolved in, the stronger the solution.

 A ratio of 1:2 is much stronger than 1:5  A ration of 1:5 is much stronger than a 1:500

Identify the strongest solution:

 A) 1:20  B) 1:200  C) 1:2

Identify the strongest solution:

 A) 1:50  B) 1:20  C) 1:100

Identify the strongest solution:

 A) 1:1000  B) 1:4000  C) 1:3000

Household & Apothecary measures  Ounce  Abbreviation: oz

Household & Apothecary measures  Ounce  Metric equivalent: 30 mL  1 oz = 30 mL  How many milliliters in 3 oz?

 90 mL  30𝑚𝐿 1𝑜𝑧 × 3𝑜𝑧 = 90 mL

Household & Apothecary measures  Tablespoon  Abbreviation: T, TBS, Tbsp  Metric equivalent: 15 mL  1 Tbsp. = 15 mL  How many milliliters in 3 Tbsp?

 45 mL (3 x 15 = 45) 15𝑚𝐿  1𝑇𝑏𝑠𝑝.

× 3𝑇𝑏𝑠𝑝

= 45mL

Household & Apothecary measures  Teaspoon  Abbreviation: t, TSP, tsp  Metric equivalent: 5 mL  So 1 tsp = 5 mL  How many milliliters in 3 tsp?

 15 mL (3 tsp x 5 mL = 15 mL)

Household & Apothecary measures  Drop  Abbreviation: gtt (gtts)  Metric equivalent: 1 mL  So 1 gtt = 1 mL  How many milliliters in 3 gtts?

 3 mL (3 x 1 = 3)

Household & Apothecary measures  Grain  Abbreviation: gr  Metric equivalent: 60 mg  1 gr = 60 mg  How many milligrams in 3 gr?

 180 mg (3 x 60 = 180)  (For grains see page 306 of your text book)

How many mL in 5 teaspoons?

A.

5 mL B.

10 mL C.

15 mL D.

25 mL E.

None of the above

How many mL in 25 drops?

A.

25 mL B.

50 mL C.

75 mL D.

100 mL E.

None of the above

The doctor says to give 2 oz, but you only have a mL cup. How much do you give in mL?

A.

2 mL B.

15 mL C.

30 mL D.

60 mL E.

None of the above

How many milligrams in 3 grains?

A.

50 mg B.

100 mg C.

150 mg D.

200 mg E.

None of the above

How many milliliters in 1 tablespoon?

A.

5 mL B.

10 mL C.

15 mL D.

25 mL E.

None of the above

True / False: A 40% solution is stronger than a 30% solution.

A.

True B.

False

True / False: A 5% ointment is stronger than a 2% ointment.

A.

True B.

False

True / False: 100mL of a 3% solution will contain 30 grams of drug.

A.

True B.

False

2.8 mL of a 5.7% solution will contain how many grams of drug? (Round to the nearest tenth) A.

B.

C.

D.

E.

2.8 g 5.7 g 0.1 g 0.2 g None of the above