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2 years ago

Questions

Chemistry

1 answer:

Ulleksa [173]2 years ago

6 0

Answers:

See below

Step-by-step explanation:

1. Most food energy

(a) Pringles

Heat from Pringles + heat absorbed by water = 0

m₁ΔH + m₂CΔT = 0

1.984ΔH + 100 × 4.184 × 18 = 0

1.984ΔH + 7530 = 0

ΔH = -7530/1.984 = -3800 J/g

(b) Cheetos

0.884ΔH + 418.4 × 13 = 0

ΔH = -5400/0.884 = -6200 J/g

Cheetos give you more food energy per gram.

(c) Snickers

Food energy = 215 Cal/28 g × 4184 J/1 Cal = 32 000 J/g

The food energy from Cheetos is much less than that from a Snickers bar

2. Experimental uncertainty

The experimental values are almost certainly too low.

Your burning food is heating up the air around it, so much of the heat of combustion is lost to the atmosphere.

3. Percent efficiency

Experimental food energy = 3800 J/g

Actual food energy = 150 Cal/28 g × 4184 J/1 Cal = 22 000 J/g

% Efficiency = Experimental value/Actual value × 100 %

= 3800/22 000 × 100 %

= 17 %

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Which material will heat the fastest?

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Answer:

Lead

Explanation:

Lower the specific heat faster it will heat, meaning liquid will heat up slowly than any other material mentioned above. Thus lead will heat up faster

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3 years ago

Glycerol (C3H8O3), also called glycerine, is widely used in the food and pharmaceutical industries. Glycerol is polar and dissol

Stells [14]

Here is the complete question.

Glycerol (C3H8O3), also called glycerine, is widely used in the food and pharmaceutical industries. Glycerol is polar and dissolves readily in water and polar organic solvents like ethanol. Calculate the mole fraction of the solvent in a solution that contains 1.61 g glycerol dissolved in 22.60 mL ethanol (CH3CH2OH; density = 0.7893 g/mol). Round to four significant digits

Answer:

0.9567 mol

Explanation:

Given that:

mass of glycerol = 1.61 g

molar mass of glycerol = 92.1 g/mol

no of mole = $\frac{mass}{molar mass}$

∴ number of moles of glycerol ( $n_{glycerol}$ ) = $\frac{1.61}{92.1}$

= 0.0175 mol

Volume of ethanol = 22.60 mL

Density of ethanol = 0.7893 g/mL

Since Density = $\frac{mass}{volume}$

∴ mass of ethanol = density of ethanol × volume of ethanol

mass of ethanol = 0.7893 g/mL × 22.60 mL

mass of ethanol = 17.838 g

Number of moles of ethanol $(n_{ethanol})$ = $\frac{17.838}{46.0684}$

= 0.387 mole

∴ the mole fraction of the solvent can be determined as:

$X_{solvent} = X_{ethanol} =$ $\frac{n_{ethanol}}{n_{glycerol}+n_{ethanol}}$

$=\frac{0.387 mol}{(0.0175+0.387)mol}$

$= \frac{0.387mol}{0.4045mol}$

= 0.95673671199

≅ 0.9567 mol

∴ The mole fraction of the solvent in a solution that contains 1.61 g glycerol dissolved in 22.60 mL ethanol is = 0.9567 mol

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3 years ago

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iron Bars form a solenoid when wrapped in a coil by a current carrying copper conducting wire .

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2 years ago

The molecular weight of table salt, NaCl, is 58.5 g/mol. A tablespoon of salt weighs 6.37 grams. Calculate the number of moles o

cestrela7 [59]

Answer:

The number of moles of salt in one tablespoon is = 0.11 mole

Grams cancel each other.

Explanation:

Moles : It is the unit of quantity . It is the mass of the substance present in exactly 12g of C-12.

$moles=\frac{given\ mass}{Molar\ mass}$

Moles Calculation:

Given mass = 6.37 gram

Molar mass = 58.5 g/mol

$moles=\frac{6.37}{58.5}$

= 0.1088

= 0.11 mole

Units calculation

$moles=\frac{given\ mass}{Molar\ mass}$

$moles=\frac{g}{g/mole}$

$moles=\frac{g}{g}\times mole$

g ang g cancels each other

moles = moles

Hence unit = gram (g ) cancel each other.

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3 years ago

Read 2 more answers

Nitrogen and hydrogen combine at a high temperature, in the presence of a catalyst, to produce ammonia. N2(g)+3H2(g)⟶2NH3(g) Ass

yaroslaw [1]

Answer:

moles of ammonia produced = 0.28 moles

Explanation:

The reaction is

$N_{2}(g)+3H_{2}(g) --> 2NH_{3}(g)$

As per equation, one mole of nitrogen will react with three moles of hydrogen to give two moles of ammonia

So 0.140 moles of nitrogen will react with = 3 X 0.140 moles of Hydrogen

= 0.42 moles of hydrogen molecule.

this will give 2 X 0.140 moles of ammonia = 0.28 moles of ammonia

the moles of ammonia produced = 0.28 moles

Here the nitrogen is limiting reagent.

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3 years ago