If an atom has an atomic mass of 16 and it has 8 neutrons what is it's atomic number

A buffer solution contains 0.479 M NaHCO3 and 0.342 M Na2CO3. Determine the pH change when 0.091 mol HNO3 is added to 1.00 L of

pshichka [43]

Answer:

ΔpH = 0.20

Explanation:

The buffer of HCO₃⁻ + CO₃²⁻ has a pka of 10.2

HCO₃⁻ ⇄ H⁺ + CO₃²⁻

There are 0.479moles of NaHCO₃ and 0.342moles of Na₂CO₃.

Using Henderson-Hasselbalch formula:

pH = pka + log [Base] / [Acid]

pH = 10.2 + log 0.342mol / 0.479mol

pH = 10.05

NaOH reacts with HCO₃⁻ producing CO₃²⁻, thus:

NaOH + HCO₃⁻ → CO₃²⁻ + H₂O + Na⁺

0.091 moles of NaOH produce the same moles of CO₃²⁻ and consume HCO₃⁻. Moles of these species are:

CO₃²⁻: 0.342mol + 0.091mol: 0.433mol

HCO₃⁻: 0.479mol - 0.091 mol: 0.388mol

Using Henderson-Hasselbalch formula:

pH = pka + log [Base] / [Acid]

pH = 10.2 + log 0.433mol / 0.388mol

pH = 10.25

That means change of pH, ΔpH is:

ΔpH = 10.25 - 10.05 = 0.20

I hope it helps!

3 0

2 years ago

Please help... I am begging...

iVinArrow [24]

Answer:

The number, such as 98.7 FM, of a radio station represents:

the frequency in which is transmitted the radio signal.

Explanation:

The radio FM is the modulated frequency, which means that all the information is sent by just a signal, with different frequencies which difference them, the radio FM use the frequencies from 88 MHz until 108 Mhz (MHz is a measuring unit for the frequency), with a minimal space among them of 0.2 MHz, this last means that you could find a signal in 88.0 MHz, and the next should be 88.2 MHz, next 88.4 MHz and so (at least, regularly the space between two frequencies is more than 0.2 MHz).

5 0

3 years ago

Which taxonomic classification level is the largest or most broad?(1 point)

patriot [66]

According to the research, domain is the taxonomic classification level that is the largest or most broad.

<h3>What is domain?</h3>

It is the broadest taxonomic category in which known living things are classified.

In other words, it is the broadest category in which the different kingdoms of life can be organized, according to the classification models that are most widely accepted in the scientific community.

Therefore, we can conclude that according to the research, domain is the taxonomic classification level that is the largest or most broad.

Learn more about taxonomic classification here: brainly.com/question/13049455

#SPJ1

7 0

2 years ago

Predict the sign of ΔS° for 2NO2(g) LaTeX: \longrightarrow⟶ N2O4(g) CaCO3(s) + 2HCl(aq) LaTeX: \longrightarrow⟶ CaCl2(aq) + H2O(

prisoha [69]

Answer: a. $2NO_2(g)\rightarrow N_2O_4(g)$ : $\Delta S$ is negative

b. $CaCO_3(s)+2HCl(aq)\rightarrow CaCl_2(aq)+H_2O(l)$ : $\Delta S$ is negative

c. $Ag^+(aq)+Cl^-(aq)\rightarrow AgCl(s)$ : $\Delta S$ is negative

Explanation:

Entropy is the measure of randomness or disorder of a system. If a system moves from an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa

a) $2NO_2(g)\rightarrow N_2O_4(g)$

In this reaction 2 moles of gaseous reactants are converting to 1 mole of gaseous products. The randomness will decrease and hence entropy will also decrease. Thus $\Delta S$ is negative.

b) $CaCO_3(s)+2HCl(aq)\rightarrow CaCl_2(aq)+H_2O(l)$

In this reaction solid reactants are converting to aqueous products. The randomness will increase and hence entropy will also increase. Thus $\Delta S$ is positive.

c) $Ag^+(aq)+Cl^-(aq)\rightarrow AgCl(s)$

In this reaction aqueous reactants are converting to solid products. The randomness will decrease and hence entropy will also decrease. Thus $\Delta S$ is negative

3 0

3 years ago

A metal sample is heated and placed into the water in a calorimeter at room temperature. Which statement best describes how the

rjkz [21]

Answer:

Energy transfers from the metal to the water and calorimeter until they are all at room temperature.

Explanation:

Calorimetry is the process that is used to determine the amount of heat that has been transferred in any process. In any chemical or physical process, the amount of energy is required. This energy is measured by the process of calorimetry. A calorimeter is a device that is used in this process. The heat that has been used in the process is measured and the change in the temperature is noted.

8 0

3 years ago