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3 years ago

What happens to the gibbs free energy term when a chemical reaction is reversed?

1 answer:

4 0

<span>When a chemical reaction is reversed the gibbs free energy has a decrease in temperature which effects the system. It is important that we test all systems before the chemical reaction is reversed so that the free energy is not lost. We want to test the temperature prior to results.</span>

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Which is heavier? A pound of cotton candy or a pound of marbles

Ugo [173]

Answer: both are equal

They weighed the same because they both a pound

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3 years ago

Read 2 more answers

The air in a living room has a mass of 60 Kg and a specific heat of 1,020 J/kg°C. What is the change in thermal energy of the ai

arlik [135]

Answer:

Q = 306 kJ

Explanation:

Given that,

Mass, m = 60 kg

Specific heat, c = 1020 J/kg°C

The temperature changes from 20°C to 25°C.

Let Q be the change in thermal energy. The formula for the heat released is given by :

$Q=mc\Delta T$

Put all the values,

$Q=60\times 1020\times (25-20)\\\\Q=306000\ J\\\\or\\\\Q=306\ kJ$

So, 306 kJ is the change in thermal energy.

4 0

3 years ago

A twenty-eight-liter volume of gas contains 11 g methane, 1.5-gram nitrogen and 16-gram carbon dioxide. Determine partial pressu

GREYUIT [131]

Based on Dalton's Law, for a mixture of gases, the total pressure is the sum of the partial pressure of each gas.

Partial pressure (p) of each gas is related to the total pressure (P) as follows:

p = X * P----------(1)

where X is the mole fraction of that gas

X = moles of a particular gas/total number of moles of all gases in the mixture--------------(2)

Step 1: Calculate the moles of each gas

Mass of methane, CH4 = 11 g

Mass of nitrogen, N2 = 1.4 g

Mass of carbon dioxide, CO2 = 16 g

# moles of CH4 = 11 g/16 gmol-1 = 0.6875

# moles of N2 = 1.4/28 = 0.05

# moles of CO2 = 16/44 = 0.3636

Total moles = 0.6875+0.05+0.3636 = 1.1011

Step2: Calculate mole fractions of each gas

Based on equation (2)

X(CH4) = 0.6875/1.1011 = 0.6244

X(N2) = 0.05/1.1011 = 0.0454

X(CO2) = 0.3636/1.1011 = 0.3302

Step 3: Calculate the total pressure

Based on ideal gas equation:

PV = nRT

given that;

V = 28 L

n = total moles = 1.1011

R = gas constant = 0.0821 Latm/mol-K

Since temp T is not given, let us consider room temperature of 25 C = 25 + 273 = 298 K

Now, P = nRT/V = 1.011*0.0821*298/28 = 0.962 atm

Step 3: Calculate partial pressures

Based on equation:

p(CH4) = 0.6244*0.962 atm = 0.601 atm

P(N2) = 0.0454*0.962 atm = 0.044 atm

P(CO2) = 0.3302*0.962 atm = 0.318 atm

4 0

3 years ago

The ammonia molecule in the diagram has the observed bond orientation because ...

aivan3 [116]

Answer:

Nitrogen has four pairs of electrons: 3 bonds and 1 lone pair in the valence shell;
Electrons repel one another based on the VSEPR theory;
Nitrogen has a total of 7 protons (its atomic number is 7) in its nucleus.

Explanation:

The shape and the bond orientation of molecules and ions are both explained by the valences shell electron pair repulsion theory (VSEPR).

Ammonia, $NH_3$ , is a molecule which contains three N-H bonds, as well as one lone pair on nitrogen. According to the VSEPR theory, molecules try to acquire a shape which would minimize the repulsion exhibited by the electron clouds present, that is, between the bonding (shared in a bond) and non-bonding (lone pair) electrons.

In VSEPR, our main step is to calculate the steric number, this is the sum of the number of bonds (ignoring the multiplicity of any bond) and the lone pairs on a central atom. In ammonia, we have 3 bonds and 1 lone pair, totaling to a steric number of 4. A steric number of 4 without any lone pairs on a central atom and just bonds would yield a tetrahedral shape with bond angles of $109.5^o$ .

Now, in this case, since we have a lone pair instead of a bond, it is repelling stronger decreasing the bond angles to about $107^o$ .

The greater the number of lone pairs, the lower the angle becomes.

To summarize:

Nitrogen has four pairs of electrons: 3 bonds and 1 lone pair in the valence shell;
Electrons repel one another based on the VSEPR theory;
Nitrogen has a total of 7 protons (its atomic number is 7) in its nucleus.

3 0

3 years ago

I have science and i have a question that says : an element is a (valuable, pure , rare) substance that is not chemically combin

mote1985 [20]

Answer:

It’s true ( pure).

Explanation:

An element is defined as a pure substance that is not chemically combined with any other elements. An element comprises of mainly the sane type of atoms.

While a compound is a substance that consists of two or more elements which are chemically combined together. This is the main difference between an element and a compound.

3 0

3 years ago