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3 years ago

What does the following energy

Chemistry

1 answer:

ale4655 [162]3 years ago

3 0

Answer:

Option A) Exothermic Reaction

Explanation:

In exothermic reaction, the energy is released. The reactants are at high energy while the products are at low energy as shown in the graph.

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You mix 200. mL of 0.400M HCl with 200. mL of 0.400M NaOH in a coffee cup calorimeter. The temperature of the solution goes from

GuDViN [60]

Answer : The enthalpy of neutralization is, 56.012 kJ/mole

Explanation :

First we have to calculate the moles of HCl and NaOH.

$\text{Moles of HCl}=\text{Concentration of HCl}\times \text{Volume of solution}=0.400mole/L\times 0.200L=0.08mol$

$\text{Moles of NaOH}=\text{Concentration of NaOH}\times \text{Volume of solution}=0.400mole/L\times 0.200L=0.08mol$

The balanced chemical reaction will be,

$HCl+NaOH\rightarrow NaCl+H_2O$

From the balanced reaction we conclude that,

As, 1 mole of HCl neutralizes by 1 mole of NaOH

So, 0.08 mole of HCl neutralizes by 0.08 mole of NaOH

Thus, the number of neutralized moles = 0.08 mole

Now we have to calculate the mass of water.

As we know that the density of water is 1 g/ml. So, the mass of water will be:

The volume of water = $200mL+200L=400mL$

$\text{Mass of water}=\text{Density of water}\times \text{Volume of water}=1g/ml\times 400mL=400g$

Now we have to calculate the heat absorbed during the reaction.

$q=m\times c\times (T_{final}-T_{initial})$

where,

q = heat absorbed = ?

$c$ = specific heat of water = $4.18J/g^oC$

m = mass of water = 400 g

$T_{final}$ = final temperature of water = $27.78^oC=273+25.10=300.78K$

$T_{initial}$ = initial temperature of metal = $25.10^oC=273+27.78=298.1K$

Now put all the given values in the above formula, we get:

$q=400g\times 4.18J/g^oC\times (300.78-298.1)K$

$q=4480.96J$

Thus, the heat released during the neutralization = -4480.96 J

Now we have to calculate the enthalpy of neutralization.

$\Delta H=\frac{q}{n}$

where,

$\Delta H$ = enthalpy of neutralization = ?

q = heat released = -4480.96 J

n = number of moles used in neutralization = 0.08 mole

$\Delta H=\frac{-4480.96J}{0.08mole}=-56012J/mole=-56.012kJ/mol$

The negative sign indicate the heat released during the reaction.

Therefore, the enthalpy of neutralization is, 56.012 kJ/mole

8 0

2 years ago

A cup of coffee has 71 mL of coffee and 127 mL of water. What is the percent volume of the coffee solution?

Anna [14]

Answer:

35.9%

Explanation:

The percent volume of the coffee solution can be calculated as follows:

% volume of coffee solution = volume of coffee/total volume of coffee solution × 100

According to this question, a cup of coffee has 71 mL of coffee and 127 mL of water. This means that, the total volume of coffee solution is;

71mL + 127mL = 198mL

% volume = 71/198 × 100

= 0.359 × 100

Percent volume of coffee solution = 35.9%

3 0

2 years ago

How many moles are equal to 1.20 x 1024 atoms of sulfur?

kakasveta [241]

1.20x1,024=1228.8 this is your answer.
hope that this helps.

8 0

2 years ago

Read 2 more answers

How much 10.0 M HNO must be added to 1.00 L of a buffer that is 0.0100 M acetic acid and 0.100 M sodium acetate to reduce the pH

Naya [18.7K]

Explanation:

It is given that molarity of acetic acid = 0.0100 M

Therefore, moles of acetic acid = molarity of acetic acid × volume of buffer

Moles of acetic acid = 0.0100 M × 1.00 L

= 0.0100 mol

Similarly, moles of acetate = molarity of sodium acetat × volume of buffer

= 0.100 mol

When $HNO_{3}$ is added, it will convert acetate to acetic acid.

Hence, new moles acetic acid = (initial moles acetic acid) + (moles $HNO_{3}$ )

= 0.0100 mol + x

New moles of sodium acetate = (initial moles acetate) - (moles $HNO_{3}$ )

= 0.100 mol - x

According to Henderson - Hasselbalch equation,

pH = $pK_{a} + log\frac{[conjugate base]}{[weak acid]}$

pH = $pKa + log\frac{(new moles of sodium acetate)}{(new moles of acetic acid)}$

4.95 = 4.75 + $log\frac{(0.100 mol - x)}{(0.0100 mol + x)}$

$log\frac{(0.100 mol - x)}{(0.0100 mol + x)}$ = 4.95 - 4.75

= 0.20

$\frac{(0.100 mol - x)}{(0.0100 mol + x)}$ = antilog (0.20)

= 1.6

Hence, x = 0.032555 mol

Therefore, moles of $HNO_{3}$ = 0.032555 mol

volume of $HNO_{3}$ = $\frac{moles HNO_{3}}{molarity of HNO_{3}}$

= $\frac{0.032555 mol}{10.0 M}$

= 0.0032555 L

or, = 3.25 (as 1 L = 1000 mL)

Thus, we can conclude that volume of $HNO_{3}$ added is 3.26 mL.

5 0

2 years ago

How does the density of a solid affect the speed of sound?

levacccp [35]

The speed of sound depends on the elasticity and density of the medium through which it is traveling, a.k.a sound travels faster in liquids than in gases and faster in solids than in liquids. The greater the elasticity and the lower the density, the faster sound travels in a medium.

6 0

3 years ago