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2 years ago

What does buffer do?? (Chemistry)

Chemistry

2 answers:

Lapatulllka [165]2 years ago

8 0

Answer:

C, It resists a change in pH when H+ or OH is added to a solution.

Explanation:

a p e x

pogonyaev2 years ago

4 0

A buffer is a solution that can resist pH change upon the addition of an acidic or basic components. It is able to neutralize small amounts of added acid or base, thus maintaining the pH of the solution relatively stable. This is important for processes and/or reactions which require specific and stable pH ranges. Buffer solutions have a working pH range and capacity which dictate how much acid/base can be neutralized before pH changes, and the amount by which it will change.

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A 45.0-gram sample of copper metal was heated from 20.0°C to 100.0°C. Calculate the heat absorbed, in kJ, by the metal.

s2008m [1.1K]

Answer:

1.386 KJ

Explanation:

From the question given above, the following data were obtained:

Mass (M) of copper = 45 g

Initial temperature (T1) = 20.0°C

Final temperature (T2) = 100.0°C

Heat absorbed (Q) =..?

Next, we shall determine the change in temperature. This can be obtained as follow:

Initial temperature (T1) = 20.0°C

Final temperature (T2) = 100.0°C

Change in temperature (ΔT) =?

ΔT = T2 – T1

ΔT = 100 – 20

ΔT = 80 °C

Next, we shall determine the heat absorbed by the sample of copper as follow:

Mass (M) of copper = 45 g

Change in temperature (ΔT) = 80 °C

Specific heat capacity (C) of copper = 0.385 J/gºC

Heat absorbed (Q) =..?

Q = MCΔT

Q = 45 × 0.385 × 80

Q = 1386 J

Finally, we shall convert 1386 J to KJ. This can be obtained as follow:

1000 J = 1 KJ

Therefore,

1386 J = 1386 J × 1 KJ /1000 J

1386 J = 1.386 KJ

Thus, the heat absorbed by the sample of the sample of copper is 1.386 KJ.

5 0

2 years ago

Given the following data:

bagirrra123 [75]

$176.0 \; \text{kJ} \cdot \text{mol}^{-1}$

As long as the equation in question can be expressed as the sum of the three equations with known enthalpy change, its $\Delta H$ can be determined with the Hess's Law. The key is to find the appropriate coefficient for each of the given equations.

Let the three equations with $\Delta H$ given be denoted as (1), (2), (3), and the last equation (4). Let $a$ , $b$ , and $c$ be letters such that $a \times (1) + b \times (2) + c \times (3) = (4)$ . This relationship shall hold for all chemicals involved.

There are three unknowns; it would thus take at least three equations to find their values. Species present on both sides of the equation would cancel out. Thus, let coefficients on the reactant side be positive and those on the product side be negative, such that duplicates would cancel out arithmetically. For instance, $3 + (-1) = 2$ shall resemble the number of $\text{H}_2$ left on the product side when the second equation is directly added to the third. Similarly

$\text{NH}_4 \text{Cl} \; (s)$ : $-2 \; a = 1$
$\text{NH}_3\; (g)$ : $-2 \; b = -1$
$\text{HCl} \; (g)$ : $2 \; c = -1$

Thus

$a = -1/2\\b = 1/2\\c = -1/2$ and

$-\frac{1}{2} \times (1) + \frac{1}{2} \times (2) - \frac{1}{2} \times (3)= (4)$

Verify this conclusion against a fourth species involved- $\text{N}_2 \; (g)$ for instance. Nitrogen isn't present in the net equation. The sum of its coefficient shall, therefore, be zero.

$a + b = -1/2 + 1/2 = 0$

Apply the Hess's Law based on the coefficients to find the enthalpy change of the last equation.

$\Delta H _{(4)} = -\frac{1}{2} \; \Delta H _{(1)} + \frac{1}{2} \; \Delta H _{(2)} - \frac{1}{2} \; \Delta H _{(3)}\\\phantom{\Delta H _{(4)}} = -\frac{1}{2} \times (-628.9)+ \frac{1}{2} \times (-92.2) - \frac{1}{2} \times (184.7) \\\phantom{\Delta H _{(4)}} = 176.0 \; \text{kJ} \cdot \text{mol}^{-1}$

3 0

3 years ago

How many electron are in 56fe 3

RSB [31]

The periodic table is arranged in a way so that with each step the number of protons in the nucleus is increased by 1. It makes it for an easy choice to designate elements with numbers - atomic numbers, because in that case atomic number shows the number of protons possessed by the nucleus. Like this:
H has 1 proton
He has 2 protons
Li has 3 protons
Be has 4 protons and so on

Each proton has a charge of +1. The other particle present in the nucleus - the neutron - has zero electrical charge and thus irrelevant when computing the charge of a nucleus. It is easy to deduce that the nucleus charge equals the number of protons (which in turn equals the atomic number). So the nucleus charges are:
for H it's+1
for He it's +2
for Li it's +3
for Be it's +4 and so on

Atom is an electroneutral particle by definition. It means it's summed charge must be 0. Since we've looked at everything within the nucleus (the protons and the neutrons) it's time we turn our gaze to the space around it, which is full of orbiting electrons. Each electron has a charge of -1. To make up for the positive charge in the nucleus you have to fill the space aroung the nucleus with negative electrons.Thanks to the elementary nature of both proton and electron charge, you simply have to take the same number of electrons as that of protons! Like this:
H has 1 proton and 1 electron
He has 2 protons and 2 electrons
Li has 3 protons and 3 electrons
Be has 4 protons and 4 electrons and so on

Fe has atomic number 26. It means that Fe has 26 protons and 26 electrons. If it's a neutral atom

You typed 3. Is it accidental? If so, then the answer is above. If not, then you could be trying to type 56Fe +3, which means an ionic iron with charge +3. Charges are formed when you have too many or too few electrons to counter-balance the prositive charge of the nucleus. Charge +3 means you're 3 electrons short to negate the nucleus positive charge.

In other words, Fe+3 has 26 protons and 23 electrons.

7 0

3 years ago

What is the concentration of the hydroxide ion given that the concentration of the hydronium ion?

Sergio039 [100]

The concentration of the hydroxide ion given that the concentration of the hydronium ion 1.0 times 10^-14 M. The reverse mathematical method used to determine the pOH can be used to get the hydroxide ion concentration from the pOH. How many hydroxide ions are there in a solution with a pOH of 5.70, for instance.

Calculate 10-5.70, or "inverse" log, on a calculator (- 5.70). It indicates that one hydroxide ion is produced by one part of the NaOH solution. Because of this, the molar concentration of hydroxide ions in the solution is the same as the molar concentration of the NaOH.

To learn more about hydroxide, click here.

brainly.com/question/4251554

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6 0

1 year ago

What type of bacteria convert the

Ksju [112]

Answer: B

Nitrifying bacterium, plural Nitrifying Bacteria, any of a small group of aerobic bacteria (family Nitrobacteraceae) that use inorganic chemicals as an energy source.

3 0

3 years ago

What does buffer do?? (Chemistry)​

What does buffer do?? (Chemistry)