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3 years ago

The tip of a match is ignited as it is struck against the matchbox. Why is this a chemical change?

Chemistry

2 answers:

Rufina [12.5K]3 years ago

8 0

The tip of the match is flammable its FLVS I did this and realy ITS MELTING ITS COLERFUL LOL omg is up with the awsners

LUCKY_DIMON [66]3 years ago

5 0

The answer is A, because of the chemical reaction taking place color can change (as in this case). Hope it helps!

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What is the percent composition of YAG (Yttrium Aluminum Garnet). The formula for

andre [41]

Answer: Y 21.38 % , Al 32.44 % and O 46.16 %

Explanation: Molar mass of YAl5O12 is 88.91 + 5·26.98+12·16

= 415.81 g/mol

m-% ( Y) = 88.91 / 415.81 = 21.38 % , m-% (Al) = 5·26.98 / 415.81 =

32.44 % , rest is Oxygen

3 0

3 years ago

If acetic acid is the only acid that vinegar contains (ka=1.8×10−5), calculate the concentration of acetic acid in the vinegar.

kicyunya [14]

Ethanoic (Acetic) acid is a weak acid and do not dissociate fully. Therefore its equilibrium state has to be considered here.

$CH_{3}COOH \ \textless \ ---\ \textgreater \ H^{+} + CH_{3}COO^{-}$

In this case pH value of the solution is necessary to calculate the concentration but it's not given here so pH = 2.88 (looked it up)

pH = 2.88 ==> $[H^{+}]$ = $10^{-2.88}$ = 0.001 $moldm^{-3}$

The change in Concentration Δ $[CH_{3}COOH]$ = 0.001 $moldm^{-3}$

  CH3COOH H+ CH3COOH
Initial   $moldm^{-3}$      $x$ 0 0

Change $moldm^{-3}$ -0.001 +0.001 +0.001

Equilibrium $moldm^{-3}$ $x$ - 0.001 0.001 0.001


Since the $k_{a}$ value is so small, the assumption
$[CH_{3}COOH]_{initial} = [CH_{3}COOH]_{equilibrium}$ can be made.

$k_{a} = [tex]= 1.8*10^{-5} = \frac{[H^{+}][CH_{3}COO^{-}]}{[CH_{3}COOH]} = \frac{0.001^{2}}{x}$

Solve for x to get the required concentration.

note: 1.)Since you need the answer in 2SF don&t round up values in the middle of the calculation like I've done here.

2.) The ICE (Initial, Change, Equilibrium) table may come in handy if you are new to problems of this kind

Hope this helps!

8 0

3 years ago

What happens when you mix hydrogine, potassium and sodium

Anika [276]

Answer:

Explanation:

As the piece of metal skitters across the surface of the water in a beaker and — particularly in the case of potassium — it appears to catch fire, it is not obvious that the explanation for both phenomena lies in the production of hydrogen gas.

3 0

3 years ago

Which has a higher frequency electron or a neutron why ?

8_murik_8 [283]

The electron has a higher frequency compared to the neutron. It can be explained by the way an electron orbits the nucleus of an atom.

According to Quantum Mechanics, electrons do not really orbit the nucleus of an atom. In fact, the most tightly bound state, the 1s orbital, has no angular momentum at all. This would be the state with the most "kinetic energy" and yet there is no "orbital" motion at all in this state.

<span>However, there are frequencies associated with each orbital.</span>

5 0

3 years ago

Calculate the ph of this solution. round to the nearest hundredth. poh = 3.45 ph =

maks197457 [2]

The potential of hydrogen pH of the solution with the given value of pOH to the nearest hundredth is 10.55.

What is pH of solution?

The pH of a solution is defined as the logarithm of the reciprocal of the hydrogen ion concentration [H+] of the given solution.

It is expressed as;

pH = -log[ H⁺ ]

Also,

pH + pOH = 14

Given that;

pOH = 3.45
pH = ?

We simply substitute our values into the expression above.

pH + pOH = 14

pH + 3.45 = 14

pH = 14 - 3.45

pH = 10.55

Therefore, the potential of hydrogen pH of the solution with the given value of pOH to the nearest hundredth is 10.55.

Learn more about pH & pOH here: brainly.com/question/17144456

#SPJ4

7 0

2 years ago