A(n) _______ is a substance of two or more atoms held together with chemical bonds.

3. How much energy is needed to raise 45 grams of water from 40°C to 115 °C?

Dafna1 [17]

Answer:

Q = 114349.5 J

Explanation:

Hello there!

In this case, since this a problem in which we need to calculate the total heat of the described process, it turns out convenient to calculate it in three steps; the first one, associated to the heating of the liquid water from 40 °C to 100 °C, next the vaporization of liquid water to steam at constant 100 °C and finally the heating of steam from 100 °C to 115 °C. In such a way, we calculate each heat as shown below:

$Q_1=45g*4.18\frac{J}{g\°C}*(100\°C-40\°C)=11286J\\\\Q_2=45g* 2260 \frac{J}{g} =101700J\\\\Q_3=45*2.02\frac{J}{g\°C}*(115\°C-100\°C)=1363.5J$

Thus, the total energy turns out to be:

$Q_T=11286J+101700J+1363.5J\\\\Q_T=114349.5J$

Best regards!

5 0

2 years ago

While you are using a battery, the cell reaction is going a) forward, b) backward, c) at equilibrium, d) TEXASIN all possible

polet [3.4K]

Answer:Cell reaction is going forward.

Explanation:

For any chemical reaction to be spontaneous or to move in forward direction the ΔG ,the Gibbs free energy must be negative.

The cell potential of a battery is positive for a spontaneous reaction, so for a battery to give output its cell potential must be positive.

Thermodynamics and electro-chemistry are related in the following manner:

ΔG=-nFE

n=number of electrons involved

F=Faradays constant

E=cell pottential of battery

so from the above equation ΔG would only be negative when E cell that is the cell potential is positive.

For a battery which is being used its cell potential is positive and hence the ΔG would be negative. So the cell reaction occurring would be in forward direction as ΔG is negative.

when the cell potential Ecell is 0 then ΔG is also zero then the reaction occurring in battery would be at equilibrium.

When the cell potential Ecell is - then ΔG is positive and the reaction would be occurring backwards.

3 0

3 years ago

Sulfur and oxygen react to produce sulfur trioxide. In a particular experiment, 7.9 grams of SO3 are produced by the reaction of

shutvik [7]

Answer:

79%

Explanation:

1) Balanced chemical equation:

2S + 3O₂ → 2SO₃

2) Mole ratio:

2 mol S : 3 mol O₂ : 2 mol SO₃

3) Limiting reactant:

Number of moles of O₂

n = 6.0 g / 32.0 g/mol = 0.1875 mol O₂

Number of moles of S:

n = 7.0 g / 32.065 g/mol = 0.2183 mol S

Ratios:

Actual ratio: 0.1875 mol O₂ / 0.2183 mol S =0.859

Theoretical ratio: 3 mol O₂ / 2 mol S = 1.5

Since there is a smaller proportion of O₂ (0.859) than the theoretical ratio (1.5), O₂ will be used before all S be consumed, and O₂ is the limiting reactant.

4) Calcuate theoretical yield (using the limiting reactant):