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3 years ago

8

Over time, an iron nail reacts with water to produce iron oxide, or rust. Which of the following is a signal that rusting has ta

ken place?

2 answers:

emmasim [6.3K]3 years ago

8 0

Explanation:

When iron reacts with the moisture present in air then an oxide layer tends to develop on the surface of iron. This process is known as rusting of iron.

Chemical formula of rust is $Fe_{2}O_{3}.xH_{2}O$ . This layer of oxide on the surface of iron is orange-brown in color.

This change is a chemical change as a new compound iron oxide has formed in this process of rusting.

Hence, this orange-brown color on the surface of iron helps us to know that rusting has taken place.

svetlana [45]3 years ago

6 0

Answer: Chemical composition modification (or, physical signal would be color).

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A gas mixture with a total pressure of 750 mmHg contains each of the following gases at the indicated partial pressures: CO2 , 1

jolli1 [7]

Answer: a) 211 mm Hg

b) 0.629 grams

Explanation:

According to Dalton's law, the total pressure is the sum of individual pressures.

$p_{total}=p_1+p_2+p_3+p_4$

$p_{total}$ = total pressure = 750 mmHg

$p_{CO_2}$ = 124 mm Hg

$p_{Ar}$ = 218 mm Hg

$p_{O_2}$ = 197 mm Hg

$p_{He}$ = ?

$750 mmHg=124 mm Hg+218 mm Hg+197 mm Hg+p_{He}$

$p_{He}=211mmHg$

Thus the partial pressure of the helium gas is 211 mmHg.

b) According to the ideal gas equation:

$PV=nRT$

P = Pressure of the gas = 211 mmHg = 0.28 atm (760mmHg=1atm)

V= Volume of the gas = 13.0 L

T= Temperature of the gas = 282 K

R= Gas constant = 0.0821 atmL/K mol

n= moles of gas= ?

$n=\frac{PV}{RT}=\frac{0.28\times 13.0}0.0821\times 282}=0.157moles$

Mass of helium= $moles\times {\text {molar mass}}=0.157\times 4=0.629g$

Thus mass of helium gas present in a 13.0-L sample of this mixture at 282 K is 0.629 grams

8 0

3 years ago

Dwayne filled a small balloon with air at 298.5 K. He put the balloon into a bucket of water, and the water level in the bucket

Tcecarenko [31]

Answer : The volume of the balloon will be, 0.494 liters

Solution :

Charles' Law : It is defined as the volume of the gas is directly proportional to the temperature of the gas at constant pressure and number of moles.

$V\propto T$

or,

$\frac{V_1}{T_1}=\frac{V_2}{T_2}$

where,

$V_1$ = initial volume of gas = ?

$V_2$ = final volume of gas = 0.54 L

$T_1$ = initial temperature of gas = 273.15 K

$T_2$ = final temperature of gas = 298.5 K

Now put all the given values in the above equation, we get the initial volume of balloon.

$\frac{V_1}{273.15K}=\frac{0.54L}{298.5K}$

$V_1=0.494L$

Therefore, the volume of the balloon will be, 0.494 liters

5 0

3 years ago

Read 2 more answers

How many moles of hydrogen gas would be needed to react with excess carbon dioxide to produce 30.6 moles of water vapor?

belka [17]

H₂ + CO₂ ⇄ CO + H₂O

1 mol H₂ - 1 mol H₂O
x mol H₂ - 30.6 mol H₂O

x=30.6*1/1=30.6 mol (<span>theoretically)</span>

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Using the clausius clapeyron equation determines the heat of vaporization from experimental measurements of vapor pressure. the

Temka [501]

The temperature of the pressure is 255

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3 years ago

Three quantum numbers are derived from Schrodinger’s equation that describe the probability of finding an electron around a nucl

hodyreva [135]

Principle: Orbital size & main energy level

Angular: Orbital shape

Magnetic: Orbital orientation

Orbital size is Principle; main energy level is Principle; shape is Angular; orientation is Magnetic

Principle:

imagine a bullseye. each ring shows how far its from the nucleus

Angular:

0 looks like circle

1 looks like a bowtie

2 looks like a flower or 4 leaf clover

3 looks like multiple lobes

Principle Quantum Number: It describes the size of the orbital and the main energy level. It is represented by n. Where, n = 1,2,3,4....stands for K, L, M, N shell and so on..

Angular momentum Quantum Number : It describes the shape of the orbital. It is represented as 'l'. The value of l ranges from 0 to (n-1). For l = 0,1,2,3... the orbitals are s, p, d, f...

Magnetic Quantum Number : It describes the orientation of the orbitals. It is represented as . The value of this quantum number ranges from . When l = 2, the value of will be -2, -1, 0, +1, +2.

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2 years ago