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3 years ago

Where is Convection When you cook a marshmallow on a metal poker tool over an open flame

Chemistry

1 answer:

Vera_Pavlovna [14]3 years ago

7 0

Answer:

this is the answer pls give me brainliest

The three ways thermal energy is transferred are;

1) Conduction

2) Convection

3) Radiation

Explanation:

1) The conduction of the heat from the open flame to the marshmallow is through the direct contact of the flame with the marshmallow, such that the flame the region of the combustion reaction, that produces light and heat touches the marshmallow

2) The convection process is the transfer of heat from the rising heated combustion products, as well as the heated air that rises from the flame

3) The radiation heat transfer is the transfer of the heat from the fire to the marshmallows directly by the heat the moves in the form of electromagnetic waves at temperatures above 1000 K, without the need for a medium, such that the marshmallow can be heated by the heat coming from side of the flame.

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Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). The balanced equation isC7H6

prisoha [69]

Answer:

For a: The mass of acetic anhydride needed is 73.91 grams.

For b: The theoretical yield of aspirin is 130.43 grams.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For a:

Given mass of salicylic acid = $1.00\times 10^2g=100g$

Molar mass of salicylic acid = 138.121 g/mol

Putting values in equation 1, we get:

$\text{Moles of salicylic acid}=\frac{100g}{138.121g/mol}=0.724mol$

For the given chemical reaction:

$C_7H_6O_3+C_4H_6O_3\rightarrow C_9H_8O_4+CH_3COOH$

By stoichiometry of the reaction:

1 mole of salicylic acid reacts with 1 mole of acetic anhydride.

So, 0.724 moles of salicylic acid will react with = $\frac{1}{1}\times 0.724=0.724mol$ of acetic anhydride.

Now, to calculate the mass of acetic anhydride, we use equation 1:

Moles of acetic anhydride = 0.724 moles

Molar mass of acetic anhydride = 102.09 g/mol

Putting values in equation 1, we get:

$0.724mol=\frac{\text{Mass of acetic anhydride}}{102.09g/mol}\\\\\text{Mass of acetic anhydride}=73.91g$

Hence, the mass of acetic anhydride needed is 73.91 grams.

For b:

By stoichiometry of the reaction:

1 mole of salicylic acid is producing 1 mole of aspirin.

So, 0.724 moles of salicylic acid will produce = $\frac{1}{1}\times 0.724=0.724mol$ of aspirin.

Now, to calculate the mass of aspirin, we use equation 1:

Moles of aspirin = 0.724 moles

Molar mass of aspirin = 180.158 g/mol

Putting values in equation 1, we get:

$0.724mol=\frac{\text{Mass of aspirin}}{180.158g/mol}\\\\\text{Mass of aspirin}=130.43g$

Hence, the theoretical yield of aspirin is 130.43 grams.

4 0

3 years ago

Round off each number to the indicated number significant figures (sf):

qaws [65]

Answer :

(a) The given number in 2 significant figures will be, $3.6\times 10^3$

(b) The given number in 4 significant figures will be, $3.583\times 10^1$

(c) The given number in 3 significant figures will be, $2.24\times 10^1$

Explanation :

Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.

(a) The given number 00003554 converted into 2 significant figures.

In 00003554, there are 4 significant figures. Now we have to convert it into 2 significant figures.

The given number in 2 significant figures will be, $3.6\times 10^3$

(b) The given number 35.8348 converted into 4 significant figures.

In 35.8348, there are 6 significant figures. Now we have to convert it into 4 significant figures.

The given number in 4 significant figures will be, $3.583\times 10^1$

(c) The given number 22.4555 converted into 3 significant figures.

In 22.4555, there are 6 significant figures. Now we have to convert it into 3 significant figures.

The given number in 3 significant figures will be, $2.24\times 10^1$

7 0

3 years ago

Volume and moles are __________ related. This relationship can be calculated by using ___________ Law.

Kryger [21]

Answer:

The correct answer is - directly; Avogadro’s.

Explanation:

At the same temperature and pressure, gases of the same or equal volume have the same number of molecules. The relation between the moles of the gases and the volume of the gases are indirectly proportional to one another at the same temperature and pressure. This law is called Avogadro's law. In the case of an ideal gas of a particular mass has the volume and moles are directly proportional.

Thus, the correct answer is - directly; Avogadro’s.

6 0

3 years ago

Jack lives in a small city in the Pacific Northwest, where the temperatures are cool all year and the sky is frequently cloudy a

kirill [66]

Answer:

Preocouparcor ,imsm oilp

Explanation:

3 0

3 years ago

On a summer day, you take a road trip through Chelan, WA, in a Tesla Model S. You start out at a temperature of 19°C in the morn

ASHA 777 [7]

1. 1.636 moles

2. 271.06 kPa pressure

3. Tires will be burst

4. 235.91 kPa

Explanation:

Step 1:

PV = nRT, is the equation to be used where

P represents pressure

V represents volume

n represents moles of gas

R is constant

T represents temperature in Kelvin

n=RT/PV

It is given that the pressure is 245 kPa at initial temperature 19 C and tire volume is 16.2 L. Temperature must be converted to Kelvin, 19 C equals 292K.

n=PV/RT ->245*16.2/(8.31*292) = 1.636

Number of moles of Nitrogen in the tire = 1.636

Step 2:

We need to find the maximum tire pressure at 50 C (323K)

P = nRT/V

Substituting the values P = (1.636 * 8.31 * 323)/16.2 = 271.06 kPa

The tire pressure at 50 C will be 271.06 kPa

Step 3

We need to figure out if the tires would burst in Chelan when the temperature is 55 C. It is given that the maximum pressure the tires can withstand is 265 kPA, so any pressure above this will cause the tire to burst. In Step-2 we calculated that the pressure is 271.06 kPA at 50 C which is more than the maximum pressure the tire can withstand. The pressure would increase further with temperature and at 55 C the pressure will be more than 271.06 kPa. So the tires are likely to burst in Chelan.

Step 4:

We need to find the pressure of Nitrogen at 19 C before the start of the trip so that tires will not burst. The pressure at 55 C is 265 kPa. Let us find the number of moles at this temperature and pressure.

n= PV/RT -> n=265*16.2/(8.31*328) = 1.575

Now let us find the pressure at 19 C.

P = nRT/V -> 1.575*8.31*292/16.2 = 235.91 kPa

8 0

3 years ago