What is the area of the throat that contains the vocal cords and produces

How much thermal energy is added to 10.0 g of ice at −20.0°C to convert it to water vapor at 120.0°C?

Sonbull [250]

Answer:

7479 cal.

31262.2 joules

Explanation:

This is a calorimetry problem where water in its three states changes from ice to vapor.

We must use, the calorimetry formula and the formula for latent heat.

Q = m . C . ΔT

Q = Clat . m

First of all, let's determine the heat for ice, before it melts.

10 g . 0.5 cal/g°C ( 0° - (-20°C) = 100 cal

Now, the ice has melted.

Q = Clat heat of fusion . 10 g

Q = 79.7 cal/g . 10 g → 797 cal

We have water at 0°, so this water has to receive heat until it becomes vapor. Let's determine that heat.

Q = m . C . ΔT

Q = 10 g . 1 cal/g°C (100°C - 0°C) → 1000 cal

Water is ready now, to become vapor so let's determine the heat.

Q = Clat heat of vaporization . m

Q = 539.4 cal/g . 10 g → 5394 cal

Finally we have vapor water, so let's determine the heat gained when this vapor changes the T° from 100°C to 120°

Q = m . C . ΔT

Q = 10 g . 0.470 cal/g°C . (120°C - 100°C) → 94 cal

Now, we have to sum all the heat that was added in all the process.

100 cal + 797 cal + 1000 cal + 5394 cal + 94 cal =7479 cal.

We can convert this unit to joules, which is more acceptable for energy terms.

1 cal is 4.18 Joules.

Then, 7479 cal are (7479 . 4.18) = 31262.2 joules

6 0

3 years ago

If a gas had a volume of 6.7 L and started at STP, what would the new pressure be

Phantasy [73]

The new pressure would be = 4.46 atm

<h3>Further explanation</h3>

Given

V₁=6.7 L(at STP, 1 atm 273 K)

V₂=1.5 L

Required

The new pressure

Solution

Boyle's Law

At a constant temperature, the gas volume is inversely proportional to the pressure applied

$\rm p_1V_1=p_2.V_2\\\\\dfrac{p_1}{p_2}=\dfrac{V_2}{V_1}$

P₂ = (P₁V₁)/V₂

P₂ = (1 atm x 6.7 L)/1.5 L

P₂ = 4.46 atm

5 0

2 years ago

If I have 20g of Sodium, how many moles of Sodium Oxide (Na2O) can be made?

Vika [28.1K]

Mass:20g

Mole=20/[2(23)+16]
=0.32 mil

8 0

3 years ago

If 45.8 grams of potassium chlorate decomposes, how many grams of oxygen gas can be produced? 2KClO3 → 2KCl + 3O2

natta225 [31]

To do this problem, we must first look at the balanced chemical equation for the decomposition of potassium chlorate:

2KClO3 --> 2KCl + 3O2 

We can take the given amount of grams, and use the molar mass of KClO3 to convert to moles. Then, we can use the stoichiometric ratios to relate moles of KClO3 to moles of O2. 

(39.09)+(35.45)+(3*15.99)= 122.51 g/ mol = molar mass of KClO3 
45.8 g KClO3/ 122.51 g/ mol KClO3 = .374 moles KClO3 
.374 mol KClO3 *(3 moles O2/2 mol KClO3)= .560 moles O2 

Once we have moles of O2, we can convert to grams of O2. 

(2*15.99)= 31.98 g/mol = molar mass of O2 
(.560 moles O2) (31.98 g/mol)= 17.91 g O2 

Hope this helps :)

3 0

3 years ago

A light-year is the distance that light travels in one year. Please select the best answer from the choices provided T F

german

Answer:True

Explanation:

Light year is the unit of distance and not a unit of time.

Light year is used to measure astronomical distances.

It is defined as the distance which light travels in one year.

The distance which light travels in one year is around 9.46 trillion kilometers

Thus 1 light year = $9.46\times 10^9$ km.

Thus the given statement that A light-year is the distance that light travels in one year is true.

7 0

3 years ago

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