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3 years ago

2. Calculate the joules of energy required to heat 454.3g of water frum 5.4°C to 98.6°C.

Chemistry

1 answer:

Tasya [4]3 years ago

7 0

Answer:

176984.38J

Explanation:

E = mC∆T

Where E is the energy in joules

M is the mass of water

C is the specific heat capacity of water =4.184J/g°C

It is known that it will take 4.184J of energy to change the temperature of water by one degree Celsius.

∆T = 98.6°c - 5.4°c

= 93.2°c

∆H = 454.3g × 4.18J/g°C × 93.2°c

= 176984.3768

176984.38J

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Light travels one million times faster than sound. How long would light take to travel from one hill to the other?

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2 years ago

The analysis of a hydrocarbon revealed that it was 85.7% C and 14.3% H by mass. When 1.77 g of the gas was stored in a 1.500-L f

gtnhenbr [62]

Answer:

The formula of hydrocarbon = $C_3H_6$

Explanation:

$Moles =\frac {Given\ mass}{Molar\ mass}$

% of C = 85.7

Molar mass of C = 12.0107 g/mol

% moles of C = 85.7 / 12.0107 = 7.14

% of H = 14.3

Molar mass of H = 1.00784 g/mol

% moles of H = 14.3 / 1.00784 = 14.19

Taking the simplest ratio for C and H as:

7.14 : 14.19 = 1 : 2

The empirical formula is = $CH_2$

Also, Given that:

Pressure = 508 Torr

Temperature = 17 °C

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15

So,

T = (17 + 273.15) K = 290.15 K

Volume = 1.500 L

Using ideal gas equation as:

$PV=nRT$

where,

P is the pressure

V is the volume

n is the number of moles

T is the temperature

R is Gas constant having value = 62.3637 L.torr/K.mol

Applying the equation as:

508 Torr × 1.500 L = n × 62.3637 L.torr/K.mol × 290.15 K

⇒n = 0.0421 moles

Given that :

Amount = 1.77 g

Molar mass = ?

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$0.0421\ moles= \frac{1.77\ g}{Molar\ mass}$

Molar mass of the hydrocarbon = 42.04 g/mol

Molecular formulas is the actual number of atoms of each element in the compound while empirical formulas is the simplest or reduced ratio of the elements in the compound.

Thus,

Molecular mass = n × Empirical mass

Where, n is any positive number from 1, 2, 3...

Mass from the Empirical formula = 1×12 + 2×1= 14 g/mol

Molar mass = 42.04 g/mol

So,

Molecular mass = n × Empirical mass

42.04 = n × 14

⇒ n = 3

The formula of hydrocarbon = $C_3H_6$

5 0

3 years ago

A chemist has a 3.25-mole sample of potassium (K) to use in an experiment. What is the mass of this sample?

s344n2d4d5 [400]

Hi!
• For this you want to convert moles to grams
• To do this you would simply multiple your moles times the atomic mass of potassium
3.25 x 39.098= 127.0685
• So your answer for this should be about 127.07 depending on how you need to round!

5 0

2 years ago

can anyone help me in explaining the metal excess defect in Non stoichiometric defects? i fail to understand it

mars1129 [50]

Non-stoichiometric defects are compounds which contain the combining elements in a ratio different from that required by their stoichiometric formula. The solids with metal excess defect contain metal in excess to the stoichiometric ratio. Such defect is caused due to either of the following reasons:
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In this, negative ions may be missing from their lattice sites leaving holes in which the electrons remain entrapped to maintain the electrical neutrality.
2. Metal excess defect due to the presence of extra cations at interstitial sites:
In this case, there are extra positive ions occupying interstitial sites and the electrons in another interstitial sites to maintain electrical neutrality. The defect may be visualized as the loss of non-metal atoms which leave their electrons behind. The excess metal ions occupy interstitial positions.

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3 years ago