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2 years ago

Why is it important to conserve or save our energy resources?

Chemistry

1 answer:

earnstyle [38]2 years ago

5 0

answer:

reducing energy use limits the number of carbon emissions in the environment
conserving energy produces a higher quality of life. Reduced emissions result in cleaner air quality
it helps create a healthier planet, or at least helps sustain the resources we already have

explanation:

credits: online research

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A 0. 1220 g vitamin c tablet was dissolved in acid. This required 11. 50 ml of 0. 01740 m kio3 to reach the endpoint. Calculate

kodGreya [7K]

86.66 % by weight of ascorbic acid in the tablet, when 0. 1220 g vitamin c tablet was dissolved in acid. This required 11. 50 ml of 0. 01740 m $KIO_3$ to reach the endpoint.

<h3>What is a balanced chemical equation?</h3>

A balanced chemical reaction is an equation that has equal numbers of each type of atom on both sides of the arrow.

$3C_6H_80_6 +3I_2 +KIO_3 +5KI +6H^+$ → $3C_6H_60_6 +6I^- +3I_2+6K^+ +3H_2O$

So, the balanced chemical equation for the reaction will be:

$3C_6H_8O_6 +KIO_3$ → $3C_6H_6O_6 +KI + 3H_2O$

That means, 3 mol of of ascorbic acid reacts with 1 mol of $KIO_3$

Moles of $KIO_3$ available is 0.0174 X 0.0115 =0.0002001 mol

Moles of ascorbic acid to be yielded should be 3 X 0.0002001 =0.0006003

So, percent mass of ascorbic acid in the tablet will be:

(0.1057 / 0.1220) X 100 %

=86.66 %

Hence, the third option is the correct answer.

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8 0

1 year ago

Bob measured out 1.60 grams of sodium. He calculates that 1.60 g of

saul85 [17]

Answer:

84.8%

Explanation:

Step 1: Given data

Bob measured out 1.60 g of Na. He forms NaCl according to the following equation.

Na + 1/2 Cl₂ ⇒ NaCl

According to this equation, he calculates that 1.60 g of sodium should produce 4.07 g of NaCl, which is the theoretical yield. However, he carries out the experiment and only makes 3.45 g of NaCl, which is the real yield.

Step 2: Calculate the percent yield.

We will use the following expression.

%yield = real yield / theoretical yield × 100%

%yield = 3.45 g / 4.07 g × 100% = 84.8%

6 0

3 years ago

What is the quantity of heat (in kJ) associated with cooling 185.5 g of water from 25.60°C to ice at -10.70°C?Heat Capacity of S

Cerrena [4.2K]

Taking into account the definition of calorimetry, sensible heat and latent heat, the amount of heat required is 37.88 kJ.

<h3>Calorimetry</h3>

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

<h3>Sensible heat</h3>

Sensible heat is defined as the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).

<h3>Latent heat</h3>

Latent heat is defined as the energy required by a quantity of substance to change state.

When this change consists of changing from a solid to a liquid phase, it is called heat of fusion and when the change occurs from a liquid to a gaseous state, it is called heat of vaporization.

<u><em>25.60 °C to 0 °C</em></u>

First of all, you should know that the freezing point of water is 0°C. That is, at 0°C, water freezes and turns into ice.

So, you must lower the temperature from 25.60°C (in liquid state) to 0°C, in order to supply heat without changing state (sensible heat).

The amount of heat a body receives or transmits is determined by:

Q = c× m× ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

In this case, you know:

c= Heat Capacity of Liquid= 4.184 $\frac{J}{gC}$
m= 185.5 g
ΔT= Tfinal - Tinitial= 0 °C - 25.60 °C= - 25.6 °C

Replacing:

Q1= 4.184 $\frac{J}{gC}$ × 185.5 g× (- 25.6 °C)

Solving:

<u><em>Change of state</em></u>

The heat Q that is necessary to provide for a mass m of a certain substance to change phase is equal to

Q = m×L

where L is called the latent heat of the substance and depends on the type of phase change.

In this case, you know:

n= 185.5 grams× $\frac{1mol}{18 grams}$ = 10.30 moles, where 18 $\frac{g}{mol}$ is the molar mass of water, that is, the amount of mass that a substance contains in one mole.

ΔHfus= 6.01 $\frac{kJ}{mol}$

Replacing:

Q2= 10.30 moles×6.01 $\frac{kJ}{mol}$

Solving:

<u><em>0 °C to -10.70 °C</em></u>

Similar to sensible heat previously calculated, you know:

c = Heat Capacity of Solid = 2.092 $\frac{J}{gC}$
m= 185.5 g
ΔT= Tfinal - Tinitial= -10.70 °C - 0 °C= -10.70 °C

Replacing:

Q3= 2.092 $\frac{J}{gC}$ × 185.5 g× (-10.70) °C

Solving:

<h3>Total heat required</h3>

The total heat required is calculated as:

Total heat required= Q1 + Q2 +Q3

Total heat required=-19,868.98 J + 61,903 J -4,152.3062 J

<u><em>Total heat required= 37,881.7138 J= 37.8817138 kJ= 37.88 kJ</em></u>

In summary, the amount of heat required is 37.88 kJ.

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7 0

2 years ago

Be sure to answer all parts. calculate δg ocell for the reaction between cr(s) and cu2+(aq). e ocell = 1.08 j/c. enter your answ

Mademuasel [1]

Answer:

$\boxed{-6.29 \times10^{5}\text{ J}}$

Explanation:

Step 1. Determine the cell potential

2×[Cr ⟶ Cr³⁺ + 3e⁻] 0.744 V

2Cr + 3Cu²⁺ ⟶ 3Cu + 2Cr³⁺ 1.086 V

Step 2. Calculate ΔG°

$\Delta G^{\circ} = -nFE_{\text{cell}}^{^{\circ}} = -6 \times 96 485 \times 1.086 = \text{-629 000 J}\\\\= \boxed{-6.29 \times10^{5}\text{ J}}$

6 0

3 years ago

The enthalpy of vaporization of Bromine is 15.4 kJ/mol. What is the energy change when 80.2 g of Br2 condenses to a liquid at 59

Aleksandr-060686 [28]

The enthalpy of vaporization of Bromine is 15.4 kJ/mol. -7.7 kJ is the energy change when 80.2 g of Br₂ condenses to a liquid at 59.5°C.

<h3>What is Enthalpy of Vaporization ?</h3>

The amount of enthalpy or energy that must be added to a liquid substance into gas substance is called Enthalpy of Vaporization. It is also known as Latent heat of vaporization.

<h3>How to find the energy change from enthalpy of vaporization ?</h3>

To calculate the energy use this expression:

$Q = n \Delta H_{\text{vapo.}$

where,

Q = Energy change

n = number of moles

$\Delta H_{\text{Vapo.}}$ = Molar enthalpy of vaporization

Now find the number of moles

Number of moles (n) = $\frac{\text{Given Mass}}{\text{Molar mass}}$

= $\frac{80.2\ g }{159.8\ g/mol}$

= 0.5 mol

Now put the values in above formula we get

$Q = - n \Delta H_{\text{vapo.}$ [Negative sign is used because Br₂ condensed here]

= - (0.5 mol × 15.4 kJ/mol)

= - 7.7 kJ

Thus from the above conclusion we can say that The enthalpy of vaporization of Bromine is 15.4 kJ/mol. -7.7 kJ is the energy change when 80.2 g of Br₂ condenses to a liquid at 59.5°C.

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8 0

1 year ago