a) The recommended daily allowance (RDA) of the trace metal magnesium is 410 mg/day for males. Express this quantity in ?g/s. Express this quantity in b) For adults, the RDA of the amino acid lysine is 12 mg per kg of body weight. How many grams per day should a 75 kg adult receive?. c) A typical multivitamin tablet can contain 2.0 mg of vitamin (riboflavin), and the RDA is 0.0030 g/day. How many such tablets should a person take each day to get the proper amount of this vitamin, assuming that he gets none from any other sources?
d.) The RDA for the trace element selenium is 0.000070 g/day . Express this dose in mg/day .
a) To convert from mg/day to µg/s, we will use the following conversions:
1 mg = 1000 µg
1 day = 24 * 60 * 60 s
Therefore, to convert 410 mg/day to µg/s:
Step 1: Convert mg to µg
410 mg/day * 1000 µg/mg = 410000 µg/day
Step 2: Convert µg/day to µg/s
410000 µg/day / (24 * 60 * 60 s) = 4.75 µg/s
So, the recommended daily allowance (RDA) of magnesium for males is 4.75 µg/s.
b) To calculate the grams per day for a 75 kg adult with an RDA of 12 mg per kg of body weight:
Step 1: Calculate the total amount needed for a 75 kg adult
12 mg/kg * 75 kg = 900 mg
Step 2: Convert mg to grams
900 mg = 0.9 grams
So, a 75 kg adult should receive 0.9 grams of lysine per day.
c) To determine how many multivitamin tablets a person should take each day to get the proper amount of riboflavin (vitamin B2):
Step 1: Convert the RDA of riboflavin to mg/day
0.0030 g/day * 1000 mg/g = 3.0 mg/day
Step 2: Divide the RDA by the amount of riboflavin in each tablet
3.0 mg/day / 2.0 mg/tablet = 1.5 tablets
Therefore, a person should take 1.5 tablets of the multivitamin each day to get the proper amount of riboflavin.
d) To convert the RDA for selenium from grams per day to mg per day:
Step 1: Convert g to mg
0.000070 g/day * 1000 mg/g = 0.07 mg/day
So, the RDA for selenium is 0.07 mg/day.
a) To convert mg/day to µg/s, we need to convert milligrams (mg) to micrograms (µg) and days to seconds.
1 mg = 1000 µg (since 1 milligram is equal to 1000 micrograms)
1 day = 24 hours × 60 minutes × 60 seconds = 86400 seconds (since 1 day has 24 hours, 60 minutes per hour, and 60 seconds per minute)
Therefore,
410 mg/day = 410 × 1000 µg/day = 410,000 µg/day
To convert to µg/s, we divide by the number of seconds in a day:
410,000 µg/day ÷ 86400 seconds/day = 4.745 µg/s (approximately)
b) To calculate the grams per day for a 75 kg adult based on the RDA per kg of body weight, we multiply the RDA value by the weight in kilograms.
RDA of lysine = 12 mg per kg of body weight
Weight of adult = 75 kg
Grams per day = (12 mg/kg) × 75 kg
= 900 mg
= 0.9 g (since 1 gram is equal to 1000 milligrams)
An adult weighing 75 kg should receive 0.9 grams (or 900 mg) of lysine per day.
c) To calculate how many vitamin tablets are needed to reach the RDA, we divide the RDA by the quantity of the vitamin in each tablet.
RDA of vitamin (riboflavin) = 0.0030 g/day
Vitamin content per tablet = 2.0 mg = 0.0020 g (since 1 gram is equal to 1000 milligrams)
Number of tablets per day = RDA ÷ Vitamin content per tablet
= 0.0030 g/day ÷ 0.0020 g/tablet
= 1.5 tablets (approximately)
Therefore, a person should take approximately 1.5 tablets each day to get the proper amount of riboflavin.
d) To express the RDA of selenium from grams per day to milligrams per day:
RDA of selenium = 0.000070 g/day
To convert grams to milligrams, multiply by 1000:
0.000070 g/day × 1000 mg/g = 0.07 mg/day
For your information:
Major minerals have RDA's (Recommended
Daily Allowance) of hundreds of milligram (mg) per day. So Magnesium is a major mineral for the human body.
Note: Iron is the trace mineral with the highest RDA at 10-15 mg/day.
(a) mg=milligram = (1/1000) gram
=> there are (1/1000) mg/g
For example,
15 mg/day = 15 mg * (1/1000) g/mg
= 15/1000 g = 0.015 g
(conversion by cancelling the units mg)
(b) RDA Lysine : 12 mg/kg body weight
Example:
For a given adult with 80 kg body weight,
RDA=12 mg/kg/day *80 kg (kg's cancel)
=12*80 mg/day
=960 mg/day
(c) Vitamin X: RDA=0.0030 g/day
2 mg/tablet
RDA=0.0030 g/day
= 0.0030 g/day * 1000 mg/g (units g cancel)
=3 mg/day
=3 mg/day ÷ 2 mg/tablet
=1.5 tablets/day
(d) Leave that to you.
Please work on the above problems and post your answers for a check if you wish.
Next time, please show your effort by posting at the same time your answers. Be ready to explain how you got your answers to help you correct any misconceptions, if any.