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3 years ago

PLEASE ANSWER ARE THESE CORRECTTTTTT

Chemistry

2 answers:

Harman [31]3 years ago

6 0

Left Frame

The answer you have chosen is not correct. You have selected a physical property. Color is something that will not change as long as nothing chemical is done to the sample. If it is just going to sit there at room temperature in a flask and be admired, (particularly if the flask has a cork in it), then whatever you see is a physical property. The only one that isn't is E. When you burn something, there is a change. One chemical turns into something else. If you burn gasoline (for your car) then C8H18 + 13.5 02 ==> 8CO2 + 9H20 is the result. That gasoline is not easily reversible. It has changed into something else (Water and Carbon Dioxide). That's Chemical.

Middle Frame

I've never encountered these terms before. Your two examples of extensive are correct. I'm not sure about the chemical reaction. I think it is intensive, but I wouldn't bet the farm on it. A chemical reaction is going to take place no matter how much is used. You could have too much sample or too much acid, but what happens does not depend on the amount. I think you are correct.

Answer: you have placed these in the right place.

Right frame.

All four are in the right category. Very nicely done.

Naddik [55]3 years ago

3 0

1. The answer is E.

2. I agree with your answers.

3. I also agree with your answers

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by definition, any substance that donates a proton is best defined as _________. a. an arrhenius acid b. an arrhenius base c. a

yuradex [85]

C a bronsted-lowry acid

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3 years ago

what is the approximate ph at the equivalence point of a weak acid-strong base titration if 25 ml of aqueous formic acid require

vivado [14]

Answer:

pH at equivalence point is 8.52

Explanation:

$HCOOH+NaOH\rightarrow HCOO^{-}Na^{+}+H_{2}O$

1 mol of HCOOH reacts with 1 mol of NaOH to produce 1 mol of $HCOO^{-}$

So, moles of NaOH used to reach equivalence point equal to number of moles $HCOO^{-}$ produced at equivalence point.

As density of water is 1g/mL, therefore molarity is equal to molality of an aqueous solution.

So, moles of $HCOO^{-}$ produced = $\frac{29.80\times 0.3567}{1000}moles=0.01063moles$

Total volume of solution at equivalence point = (25+29.80) mL = 54.80 mL

So, at equivalence point concentration of $HCOO^{-}$ = $\frac{0.01063\times 1000}{54.80}M=0.1940M$

At equivalence point, pH depends upon hydrolysis of $HCOO^{-}$ . So, we have to construct an ICE table.

$HCOO^{-}+H_{2}O\rightleftharpoons HCOOH+OH^{-}$

I: 0.1940 0 0

C: -x +x +x

E: 0.1940-x x x

So, $\frac{[HCOOH][OH^{-}]}{[HCOO^{-}]}=K_{b}(HCOO^{-})=\frac{10^{-14}}{Ka(HCOOH)}$

species inside third bracket represent equilibrium concentrations

So, $\frac{x^{2}}{0.1940-x}=5.56\times 10^{-11}$

or, $x^{2}+(5.56\times 10^{-11}\times x)-(1.079\times 10^{-11})=0$

So, $x=\frac{-(5.56\times 10^{-11})+\sqrt{(5.56\times 10^{-11})^{2}+(4\times 1.079\times 10^{-11})}}{2}$

So, $x=3.285\times 10^{-6}M$

So, $pH=14-pOH=14+log[OH^{-}]=14+logx=14+log(3.285\times 10^{-6})=8.52$

5 0

3 years ago

In the reaction

user100 [1]

Answer:

a) KOH

Explanation:

In the given balanced reaction

2K + 2H2O → 2KOH + H2

In the compound KOH,

The elements are K,O, and H and in the compound, there is one mole each of K , O ,and H.

So the element ratio here is 1 : 1 : 1.

7 0

3 years ago

Read 2 more answers

What is the ratio of the magenta phenolphthalein concentration to the colorless phenolphthalein concentration ([magenta phenolph

lilavasa [31]

Answer:

$\frac{[magenta\ phenolphthalein]}{[colorless\ phenolphthalein]}=31.62$

Explanation:

Considering the Henderson- Hasselbalch equation for the calculation of the pH of the buffer solution as:

$pH=pKa+\log\frac{[base]}{[acid]}$

Where Ka is the dissociation constant of the acid.

pKa of phenolphthalein = 9.40

pH = 10.9

So,

$10.9=9.40+\log\frac{[magenta\ phenolphthalein]}{[colorless\ phenolphthalein]}$

$\frac{[magenta\ phenolphthalein]}{[colorless\ phenolphthalein]}=31.62$

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3 years ago

Which determines how atoms combine to form molecules?

arlik [135]

Will be letter E cause all of them can combine molecule

7 0

4 years ago