3.01 × 1023 molecules H2O

I’ll mark u BRAINIEST if it CORRECT! This is one attempt so don’t guess!

Fiesta28 [93]

Answer:

If Methyl orange is used as only indicator, it's used in the scenario " strong acid to weak base"

Explanation:

A reaction between a weak acid and weak base, gives not strong enough changes in pH. The neutralization reaction (might) happen. But it would be difficult to get the titration curves. This means no indicator is suitable.

A strong acid to a weak base : The equivalence point for titrations between strong acids and weak bases occurs somewhere upward of pH=3-4, this depends on how strong the acid and the base.

⇒ A good indicator for this scenario is Methyl orange, because it changes colour between a pH of 3.1 - 4.4. We notice that the equivalence point is more or less in the middle of this range. This makes the indicator an useful one !

A weak acid to a strong base : The equivalence point for titrations between weak acids and strong bases occurs somewhere upward of pH=7, this depends on how strong the acid and the base.

⇒ A good indicator for this scenario is phenolphthalein, because it changes colour between a pH of roughly 8 - 10. We notice that the equivalence point is more or less in the middle of this range. This makes the indicator an useful one !

⇒Methyl orange has an equivalence point, more or less at pH=4, ( so will change colour there). This is quite away from where the equivalence point of a weak acid with a strong base.

HCl with sodium carbonate: Since this reaction has 2 end points (one at pH = 8.5 and one at pH =3.5). Methyl orange has range between pH = 3.1 and 4.4 ; phenolphthalein has a range between 8.3 and 10. Since it's colourless below pH 8, it does not interfer with the methyl orange.

For this scenario methyl orange is ONE of the indicators that can be used. As only indicator, it does not have a full spectrum of colour change. So the otherindicator that should be used is phenolphthalein.

If Methyl orange is used as only indicator, it's used in the scenario " strong acid to weak base"

4 0

3 years ago

What is the mass of H2O produced when 10.0 grams of H2 react completely with 80.0 grams of O2

ohaa [14]

$2 \ H_2 + O_2 \to 2 \ H_2O$
2 moles of H₂ : 1 mole of O₂ : 2 moles of H₂O

number of moles of H₂ : number of moles of H₂O = 1 : 1

$m_{H_2}=10 \ g \\
M_{H_2}=2 \ \frac{g}{mol} \\
n_{H_2}=\frac{10 \ g}{2 \frac{g}{mol}}=5 \ mol$

There are 5 moles of hydrogen so there must be 5 moles of water too.
$n_{H_2O}=5 \ mol \\
M_{H_2O}=18 \ \frac{g}{mol} \\
m_{H_2O}=5 \ mol \times 18 \ \frac{g}{mol}=90 \ g$

The mass of H₂O is 90 g.

5 0

4 years ago

I will give you a brainliest and a thanks if you answer this correctly

FrozenT [24]

Answer:

Because energy is conserved, the kinetic energy of a block at the bottom of a frictionless

ramp is equal to the gravitational potential energy of the block at the top of the ramp. This

value is proportional to the square of the block’s velocity at the bottom of the ramp.

Therefore, the block’s final velocity depends on the height of the ramp but not the steepness

of the ramp

Explanation:

5 0

3 years ago

Cytoplasm

gtnhenbr [62]

Answer:

The structure found only in a plant cell is, cell wall

The answer to 19 is b

Explanation:

8 0

3 years ago

Aluminium containers are used to store and transport nitric acid(HNO3) but not NAOH why?

alex41 [277]

Answer:

(i) Concentrated HNO3 can be stored and transported in aluminium containers as it reacts with aluminium to form a thin protective oxide layer on the aluminium surface. This oxide layer renders aluminium passive. (ii) Sodium hydroxide and aluminium react to form sodium tetrahydroxoaluminate(III) and hydrogen gas.

8 0

3 years ago