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3 years ago

5

2. List and elaborate on at least two limitations of the 24-hour recall as a

1 answer:

Pavlova-9 [17]3 years ago

5 0

Answer:

The correct answer is - may not be typical, and participant burden.

Explanation:

The 24-hour recall is nothing but a retrospective method of diet assessment. In this method, an individual is interviewed about his or her diet consumption during the last 24 hours.

The disadvantages or limitations of this method include the inability of a single day's intake to describe the typical diet, multiple recalls to intake, cost and administration time; participant burden, have to recall to reliably estimate usual intake.

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How to find the average speed of something

Mila [183]

Answer:

if you want to find average speed so u need to use this formula

Average speed = $\frac{Total Displacement}{Total Time}$

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3 years ago

what mass of grams of hydrogen sulfide will be required to participate 15 g of copper sulphide from a copper (ii) traoxosulphate

cestrela7 [59]

Characteristics of a Precipitate:
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3 years ago

7. Write a formula for each of the following:

sergeinik [125]

Answer : The formula for each of the following is:

(a) $C_{22}H_{46}$

(b) $C_{17}H_{34}$

(c) $C_{13}H_{24}$

Explanation :

Alkanes are hydrocarbon in which the carbon atoms are connected with single covalent bonds.

The general formula of alkanes is $C_n H_{2n+2}$ where n is the number of the carbon atoms present in a molecule of alkane.

Alkenes are hydrocarbon in which the carbon atoms are connected with double covalent bonds.

The general formula of alkenes is $C_n H_{2n}$ where n is the number of the carbon atoms present in a molecule of alkene.

Alkynes are hydrocarbon in which the carbon atoms are connected with triple covalent bonds.

The general formula of alkynes is $C_n H_{2n-2}$ where n is the number of the carbon atoms present in a molecule of alkyne.

(a) An alkane with 22 carbon atoms

Putting n = 22 in the general formula of alkane, we get the formula of alkane as, $C_{22}H_{2(22)+2}$ or $C_{22}H_{46}$

(b) An alkene with 17 carbon atoms

Putting n = 17 in the general formula of alkene, we get the formula of alkene as, $C_{17}H_{2(17)}$ or $C_{17}H_{34}$

(c) An alkyne with 13 carbon atoms

Putting n = 13 in the general formula of alkyne, we get the formula of alkyne as, $C_{13}H_{2(13)-2}$ or $C_{13}H_{24}$

3 0

3 years ago

Read 2 more answers

This question has multiple parts. Work all the parts to get the most points. An aqueous antifreeze solution is 39.0% ethylene gl

nlexa [21]

Answer:

Molality = <u>10.300 m</u>

<u>Molarity = 6.5970 M</u>

<u>mole fraction = </u>0.156549

Explanation:

39.0 % = ethylene glycol

61.0 % = water

imagine the total mass = 100g

39.0% ethylene glycol = 39g

61.0 % water = 61g

1) Molality = number of moles / mass of solvent (kg)

Molar mass of ethylene glycol = 62.07g/mole

mole = 39g / 62.07g/mole = 0.6283 moles

Molality = moles / mass of solvent = 0.6283 moles / 0.061kg = <u>10.300 m</u>

<u />

<u>2) Molarity</u> = number of moles / volume of solution

Since we know the density of the solution = 1.05g /ml

⇒ volume = 100g / 1.05g /mL = 95.24 mL = 0.09524 L

Molarity = 0.6283 moles / 0.09524 L = <u>6.5970 M</u>

3) Mole fraction

moles water = 61g / 18.02g/mole = 3.38513 moles

Total number of moles = moles of ethylene glycol + moles of water = 0.6283 + 3.38513 = 4.0134276 moles

Mole fraction = 0.6283/ 4.0134276 = 0.156549

3 0

3 years ago

Help pls I will mark brainlest

defon

Resources found in lithosphere: gold and iron etc

Resources found in atmosphere: Water vapor, gases etc.

4 0

3 years ago