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3 years ago

In which of these situations is convection most likely the main form of heat transfer?

Chemistry

2 answers:

tatiyna3 years ago

7 0

Answer:

Warm air from a heater on the first floor of a house moves to the upper floors.

Explanation:

lorasvet [3.4K]3 years ago

5 0

In the first situation: the mechanism of covection is the main form of heat transfer when warm air from a heater moves around and upward.

In the case of the metal pan the mechanism of heat transfer is conduction.

In the case of sunburn the mechanism is radiation.

In the case of an ice cube melting in a hand, conduction is the most important mechanism.

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A reaction of 41.9 g of Na and 30.3 g of Br2 yields 36.4 g of NaBr . What is the percent yield?

Licemer1 [7]

Answer: The percent yield is, 93.4%

Explanation:

First we have to calculate the moles of Na.

$\text{Moles of Na}=\frac{\text{Mass of Na}}{\text{Molar mass of Na}}=\frac{41.9g}{23g/mole}=1.82moles$

Now we have to calculate the moles of $Br_2$

${\text{Moles of}Br_2} = \frac{\text{Mass of }Br_2 }{\text{Molar mass of} Br_2} =\frac{30.3g}{160g/mole}=0.189moles$

${\text{Moles of } NaBr} = \frac{\text{Mass of } NaBr }{\text{Molar mass of } NaBr} =\frac{36.4g}{103g/mole}=0.353moles$

The balanced chemical reaction is,

$2Na(s)+Br_2(g)\rightarrow 2NaBr$

As, 1 mole of bromine react with = 2 moles of Sodium

So, 0.189 moles of bromine react with = $\frac{2}{1}\times 0.189=0.378$ moles of Sodium

Thus bromine is the limiting reagent as it limits the formation of product and Na is the excess reagent.

As, 1 mole of bromine give = 2 moles of Sodium bromide

So, 0.189 moles of bromine give = $\frac{2}{1}\times 0.189=0.378$ moles of Sodium bromide

Now we have to calculate the percent yield of reaction

$\%\text{ yield}=\frac{\text{Actual yield}}{\text{Theoretical yield}}\times 100=\frac{0.353 mol}{0.378}\times 100=93.4\%$

Therefore, the percent yield is, 93.4%

3 0

3 years ago

What is the molarity of 0.26 mol of H2SO4 dissolved in 0.3 L of solution? *

irina1246 [14]

Answer:

Explanation:

molarity=moles of solute/liter of solution

molarity=0.26/0.3

molarity=0.87molar

7 0

3 years ago

4. A student purified a 500-mg sample of phthalic acid by recrystallization from water. The published solubility of phthalic aci

kupik [55]

Answer:

2.77 mL of boiling water is the minimum amount which will dissolve 500 mg of phthalic acid.

Explanation:

We know from the problem that 18 g of phthalic acid are dissolved in 100 mL of water at 99 °C.

Now we devise the following reasoning:

If 18 g of phthalic acid are dissolved in 100 mL of water at 99 °C

Then 0.5 g of phthalic acid are dissolved in X mL of water at 99 °C

X = (0.5 × 100) / 18 = 2.77 mL of water

7 0

3 years ago

WHICH OF THE GENOTYPES IN NUMBER 1 WOULD BE CONSIDERED PUREBRED

Rasek [7]

Purebred<span> — Also called HOMOZYGOUS and consists of gene pairs with genes that are the SAME. Hybrid - Also called HETEROZYGOUS and consists of gene pairs that are D i'FFEREN'i". </span>Genotype<span> is the actual GENE makeup represented by LE'H'ERS.</span>

3 0

3 years ago

What is the concentration of 10.00 mL of HBr if it takes 16.73 mL of a 0.253 M LiOH solution to neutralize it?

Leni [432]

First. let's write the reaction formula: HBr +LiOH ----> LiBr + H₂O

let's get the moles of LiOH first

moles= Molarity x Liters

moles= 0.253 M x 0.01673 Liter= 0.00423 moles LiOH

using the balanced equation, you can see that 1 mol LiOH is equal to 1 mol HBr. so:

0.00423 mol LiOH = 0.00423 mol HBr

now let's find the concentration

molarity= mol/ Liters

0.00423 mol/ 0.01000 Liters= 0.423 M

3 0

3 years ago