A breakfast of cereal, orange juice, and milk might contain 230 nutritional Calories. How much is this in Joules?

500. ml of a solution containing 1. 5 m nh4cl(aq) is mixed with 500. ml of a solution containing 0. 50m of naoh(aq). what is the

Sladkaya [172]

The pH of the solution is determined by the hydrogen ion concentration. The pH of the solution with 1.5 M NH4Cl and 0.50 M NaOH is 8.77.

The potential of the hydrogen ion in the given solution is called pH which determines the acidity and basicity of the solution.

Given

The molar concentration of 500 mL NH4Cl = 1.5 M

The molar concentration of 500 mL NaOH= 0.50 M

Kb (NH3) = 1.8 × 10 -5

First pOH is calculated as,

pOH = pKB + log [NH4Cl][NaOH]

= - log 1.8 × 10-5 + log [1.5][0.50]

= - log 1.8 × 10-5 + log [3]

= 4.744 + 0.477

= 5.221

Now, pH is calculated from pOH as,

pH + pOH = 14

pH = 14 – pOH

= 14 – 5.221

= 8.77

Thus we found that, 8.77 is the pH of the solution with 1.5 M NH4Cl and 0.50 M NaOH.

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3 0

2 years ago

At 298 K, Kc = 1.45 for the following reaction 2 BrCl (g) Br2(g) + Cl2(g) A reaction mixture was prepared with the following ini

tester [92]

Answer:

[BrCl]=0.02934M

[Br2]=[Cl2]=0.03533M

Explanation:

First, consider the Kc definition:

$1.5=K_{c}=\frac{[Br_{2}][Cl_{2}]}{[BrCl]^{2}}$

It is necessary to define a new variable, 'x', as the amount of moles of Br2 that are produced. If 'x' moles of Br2 are produced, the moles of the compounds will be calculated as;

$n_{Br_{2}}=n_{{Br_{2}}^{0}} +x\\n_{Cl_{2}}=n_{{Cl_{2}}^{0}} +x\\n_{BrCl}=n_{{BrCl}}^{0}} -2x\\$

Where the zero superscript means the initial moles.

Dividing the last equations by the volume, which is constant because the reaction does not change the total moles number (2 moles of BrCl produce 2 moles, one of Cl2 and another of Br2), we have the molarity equations for all species:

$M_{Br_{2}}=M_{{Br_{2}}^{0}} +x\\M_{Cl_{2}}=\\M_{BrCl}=M_{{BrCl}}^{0}} -2x\\$

And now 'x' is a change in molarity.

Replacing these in the Kc equation we have:

$1.45=\frac{({M_{{Br_{2}}}^{0}}+x)({M_{{Cl_{2}}}^{0}}+x)}{({M_{{BrCl}}^{0}}-2x)^{2}}$

Where the only unknown is 'x'. So, let's solve the equation:

$1.45=\frac{(0.03+x)(0.03+x)}{(0.04-2x)^{2} } \\1.45(0.04-2x)^2=(0.03+x)^2\\1.45(0.0016-0.16x+4x^2)=0.0009+0.06x+x^2\\4.8x^2-0.292x+0.00142=0\\x_{1}=0.0555\\x_{2}=0.00533$

The result $x_{1}=0.0555$ lacks of sense because it will give a negative concentration for BrCl, so the result is $x_{2}=0.00533$ <u>.</u>

Applying the result, the concentrations at equilibrium are:

$M_{Br_{2}}=M_{Cl_{2}}=0.03+0.00533=0.03533M\\M_{BrCl}=0.04-2*0.00533=0.02934M$

If you calculate Kc with this concentrations it will give 1.45 as a result.

Greets, I will be happy to solve any doubt you have.

8 0

4 years ago

Which of the following must be true about a reaction if it is only spontaneous at high temperatures?

Neporo4naja [7]

The correct answer is B,
<span>It is endothermic, with both positive enthalpy and entropy changes.</span>

4 0

3 years ago

Phosphorus oxychloride has the chemical formula POCl3, with P as the central atom. In order to minimize formal charge, how many

Elina [12.6K]

Answer:

Phosphorus makes 5 bonds with other atoms

Explanation:

$POCl_{3}$ has total 32 number of valence electrons (P has 5 , O has 6 and Cl has 7 valence electrons).

These valence electrons are used to draw Lewis structure of $POCl_{3}$ .

Formal charge on an atom = (no. of valence electrons of the atom)-(no. of covalent bonds attached to the atom)-(no. of electrons in lone pair of the atom)

Applying octet rule (atoms have eight electrons in their valence shell) and minimizing formal charge of $POCl_{3}$ , it has been found that P makes total 5 bonds with rest of the atoms.

Lewis structure of $POCl_{3}$ along with formal charge (in parentheses) has been given below.

6 0

3 years ago

Why do you think the mass of the egg changed in water and salt water?

Salsk061 [2.6K]

Salt water has more particles and causes more change to the egg while normal water has no impact on the egg because it has less chemicals.

5 0

3 years ago