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# Determine the energy needed to quench a hot gas with water

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Assume we have a 100,000 cubic foot per minute gas (air) stream at 700 degrees F that goes to an air pollution control device; also assume the hot air has no moisture content.

If 50 degree F cooling water is used, and the desire is to cool the hot air from 700 degrees F to 175 degrees F, how much 50 degree F water is needed to quench the gas? And what would be the final temperature of the cooling/quench water after it has cooled the gas?

Assume atmospheric pressure prevails.

https://brainmass.com/engineering/molecular-engineering/energy-needed-quench-hot-gas-water-129761

#### Solution Preview

For 100% efficient heat exchanger we have:
Qair = Qwater

but Qair = mcdeltaT
m = 100,000 ft^3/min = 100,000 ft^3/min*density of air
Here the air changes from 700F to 175F. So we need to use the density of air at the mean temperature 875/2 = 437F. At this temperature, density of air = 0.089(lb/ft^3) (see reference 1)
Thus m = 100,000*0.089 = 8900 (lb/min)
c = specific heat of air at ...

#### Solution Summary

The energy needed to quench a hot gas with water is calculated.

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## Nutrition - Health and Weight of Children and Teens, Breastfeeding, Nutrient Requirements

1. Identify at least 2 influences that are affecting the health and weight of children and teens.

2. What are 2 advantages and 2 disadvantages of breast feeding and formula feeding? (You will have a total of 8 answers.)

3. Describe the "Division of Responsibility Theory" and relate how the concepts may help in handling picky eaters.

4. Describe the nutrient requirements for the following life stage groups: (Note which nutrients have higher or lower recommendations.)

Pregnancy
Infants
Toddlers

5.

a. Premature infants have different nutrient needs from term infants.
True or False, Why?

b. A newborn has the highest energy and protein needs (per unit of body weight) than any other life cycle. True or False, Why?

c. Adding cereal to a 2 month old infant's bottle is recommended, and will help him sleep better at night. True or False, Why?

d. Putting a baby to bed with a bottle is a good way to make sure they will not be hungry during the night. True or False, Why?

e. Overweight women who get pregnant should not gain any additional weight. True or False, Why?

f. Pregnant teens have higher nutrient needs than pregnant adults. True or False, Why?

g. Breastmilk is better than infant formula. True or False, Why?

h. Women need nutritional supplements to meet their needs during pregnancy. True or False, Why?

I. Consuming alcohol after the third month of pregnancy has no ill effects on the fetus. True or False, Why?

j. Breastfed babies should be given bottles for the first few days of life because the mother's first milk is thin and watery and low in nutrients. True or False, Why?

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