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3 years ago

2 questions, please help!!

Chemistry

1 answer:

Amanda [17]3 years ago

7 0

i'd go for universal indicator, bromothymol blue and methyl red

i mean, they have the degrees of acidity (specific color changes)

they have wider ranges of color changes which will lead to the strength of acid

you will know the degree of acidity of the cosmetics

in fact, bromothymol blue is used to detect the slightest level of acid or base in a substance

universal indicator has the pH charts; the range is big so that you can measure the level of acidity effectively

methyl red is sensitive too as the other two mentioned earlier

the other way that's not included in your choices is the pH meter

unlike litmus papers which just have 2 results; either red or blue

phenolphthalein only colorless, pale pink

you won't know the degree of acidity

hope that helps

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A sealed can with an internal pressure of 721 mmHg at

Alexxandr [17]

Answer:

2486 mmHg

Explanation:

Gay-Lussac's Law states the pressure varies directly with temperature when volume remains constant:

P₁/T₁ = P₂/T₂

Where P₁ and T₁ are initial pressure and temperature and P₂ and T₂ are final pressure and temperatue.

The problem says initial pressure is 721 mmHg, initial temperature is 25°C and final temperature is 755°C. The question is final pressure.

°C must be converted to absolute temperature (K), thus:

25°C + 273,15 = 298,15 K

755°C + 273,15 = 1028,15 K

Thus, pressure P₂ is:

(T₂·P₁) / T₁ = P₂

1028,15K · 721mmHg / 298,15 K = 2486 mmHg

I hope it helps!

7 0

4 years ago

What is the molarity of ZnCl2 that forms when 25.0 g of zinc completely reacts with CuCl2 according to the following reaction? A

yaroslaw [1]

The ZnCl₂ solution have a molarity of 1.33 M.

Explanation:

We have the following chemical reaction:

Zn (s) + CuCl₂ (aq) → ZnCl₂ (aq) + Cu (s)

number of moles = mass / molar weight

number of moles of Zn = 25 / 65.4 = 0.38 moles

From the chemical equation we see that 1 moles of Zn produces 1 mole of ZnCl₂, so 0.38 moles of Zn will produce 0.38 moles of ZnCl₂.

molarity = number of moles / volume (L)

molarity of the ZnCl₂ solution = 0.38 / 0.285 = 1.33 M

Learn more about:

molarity

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7 0

3 years ago

The noble-gas notation for tin (Sn) will contain the symbol Ar Kr Xe Rn

KIM [24]

Answer: Noble-gas notation of Sn contains Kr.

Explanation: Tin ( Sn) is an element having atomic number 50.

Nearest noble gas to this element is Krypton which has an atomic number 36.

Electronic configuration or noble-gas notation for Sn is written as :

$Sn=[Kr]4d^{10}5s^25p^2$

As seen from above, Noble gas Krypton having symbol 'Kr' is coming in the electronic configuration for Tin.

3 0

3 years ago

Read 2 more answers

Write the parts of the ear in their correct order of transfer of vibrations. to the brain.

dimaraw [331]

Answer:

The sound waves travel from the outer ear and in through the auditory canal, causing the eardrum, or tympanic membrane, to vibrate. This, in turn, causes the three small bones, known as the ossicles, or the hammer, the anvil and the stirrup, in the middle ear to move.

3 0

3 years ago

Read 2 more answers

To what volume should you dilute 122 mL of an 8.20 M CuCl2 solution so that 51.0 mL of the diluted solution contains 4.40 g CuCl

BartSMP [9]

Answer:

<h2>The first thing to do here is to use the molarity and the volume of the initial solution to figure out how many grams of copper(II) chloride it contains.</h2><h2 /><h2>133</h2><h2>mL solution</h2><h2>⋅</h2><h2>1</h2><h2>L</h2><h2>10</h2><h2>3</h2><h2>mL</h2><h2>⋅</h2><h2>7.90 moles CuCl</h2><h2>2</h2><h2>1</h2><h2>L solution</h2><h2>=</h2><h2>1.051 moles CuCl</h2><h2>2</h2><h2 /><h2>To convert this to grams, use the compound's molar mass</h2><h2 /><h2>1.051</h2><h2>moles CuCl</h2><h2>2</h2><h2>⋅</h2><h2>134.45 g</h2><h2>1</h2><h2>mole CuCl</h2><h2>2</h2><h2>=</h2><h2>141.31 g CuCl</h2><h2>2</h2><h2 /><h2>Now, you know that the diluted solution must contain </h2><h2>4.49 g</h2><h2> of copper(II) chloride. As you know, when you dilute a solution, you increase the amount of solvent while keeping the amount of solute constant.</h2><h2 /><h2>This means that you must figure out what volume of the initial solution will contain </h2><h2>4.49 g</h2><h2> of copper(II) chloride, the solute.</h2><h2 /><h2>4.49</h2><h2>g</h2><h2>⋅</h2><h2>133 mL solution</h2><h2>141.32</h2><h2>g</h2><h2>=</h2><h2>4.23 mL solution</h2><h2>−−−−−−−−−−−−−− </h2><h2 /><h2>The answer is rounded to three sig figs.</h2><h2 /><h2>You can thus say that when you dilute </h2><h2>4.23 mL</h2><h2> of </h2><h2>7.90 M</h2><h2> copper(II) chloride solution to a total volume of </h2><h2>51.5 mL</h2><h2> , you will have a solution that contains </h2><h2>4.49 g</h2><h2> of copper(II) chloride.</h2>

3 0

3 years ago