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3 years ago

I need help with this question. Will give 5 stars

Chemistry

2 answers:

Arisa [49]3 years ago

5 0

Answer:

yes

Explanation:

Harlamova29_29 [7]3 years ago

3 0

Answer:

What is the question?

Explanation:

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I NEED HELP PLEASE!!

VikaD [51]

Answer:

The amount of heat absorbed is 5.183889 kJ .

Explanation:

In conversion of water to ice it rejects some heat while in conversion of ice to water it absorbs heat which is called latent heat which is given as 6.02 kJ/mol.

The amount of ice given is 15.5 g.

Converting it to moles as the latent heat is given in per moles:

$\frac{given\\weight \\ (in\\grams)}{molecular\\weight\\(in\\grams)}$

Molecular mass of Hydrogen (H) and Oxygen (O) is 1 u and 16 u respectively.

Molecular mass of water is 18 g ( $H_{2} O$ ⇒ 2*1+16=18 ).

mole = 15.5/18 ≈ 0.8611 moles

Therefore the amount of heat absorbed by 15.5 g of ice ( 0.8611 moles) = Latent heat * moles

Heat absorbed = 6.02*0.8611

= 6.02*(15.5/18)

≈ 5.183889 kJ

5 0

3 years ago

What is the pH at the equivalence point in the titration of a 25.7 mL sample of a 0.370 M aqueous nitrous acid solution with a 0

expeople1 [14]

Answer:

pH = 8.24

Explanation:

Nitrous acid (HNO₂) reacts with KOH, thus:

HNO₂ + KOH → KNO₂ + H₂O

Moles of HNO₂ are:

0.0257mL ₓ (0.370mol / L) = 0.00951moles.

In equivalence point, the complete moles of nitrous acid reacts with KOH producing potassium nitrite. There are needed:

0.00951mol ₓ (1L / 0.491mol) = 0.01937L ≡ 19.4mL of 0.491M KOH to reach equivalence point.

Total volume in equivalence point is: 19.4mL + 25.7mL = 45.1mL

Potassium nitrite is in equilibrium with water, thus:

NO₂⁻ + H₂O ⇄ HNO₂ + OH⁻

Where equilibrium constant, Kb, is defined as:

Kb = 1.41x10⁻¹¹ = $\frac{[OH^-][HNO_2]}{[NO_2]}$

In equilibrium, molarity of each compound are:

[NO₂⁻]: 0.00951mol/0.00451L - X = 0.211M - X

[HNO₂]: X

[OH⁻]: X

Where X is reaction coordinate

Replacing in Kb:

1.41x10⁻¹¹ = $\frac{[X][X]}{[0.211 -X]}$

0 = X² + 1.41x10⁻¹¹X - 2.97x10⁻¹²

Solving for X:

X = -1.72x10⁻⁶ FALSE ANSWER. There is no negative concentrations.

X = 1.72x10⁻⁶. Right answer.

That means:

[OH⁻]: 1.72x10⁻⁶M

As pOH is -log [OH⁻] and pH = 14-pOH:

pOH = 5.76; pH = 8.24

3 0

3 years ago

Two species of frog mate in the same pond. One breeds in early summer and one in late summer. This is an example of what kind of

MatroZZZ [7]

Answer:

Pre-zygotic, temporal separation

Explanation:

Reproductive isolation mechanism is of two types:

Prezygotic mechanism
Postzygotic mechanism

Prezygotic mechanism isolation occurs before fertilization and helpful in preventing formation of fertile offspring.

In frog external fertilization occurs. In the external fertilization, eggs and sperms are released in water and fertilization occur outside the water.

Prezygotic isolating mechanisms may include behavioral isolation, temporal isolation, mechanical isolation, gametic isolation and habitat isolation.

Temporal separation in reproduction is the sexual activity in the same geographical range but in different periods.

Therefore, the given reproductive isolation is pre-zygotic, temporal separation.

4 0

3 years ago

Silver nitrate solution reacts with calcium chloride solution according to the equation: 2 AgNO3 + CaCl2 → Ca(NO3)2 + 2 AgCl All

HACTEHA [7]

Answer:

14.33 g

Explanation:

Solve this problem based on the stoichiometry of the reaction.

To do that we need the molecular weight of the masses involved and then calculate the number of moles, find the limiting reagent and finally calculate the mass of AgCl.

2 AgNO₃ + CaCl₂ ⇒ Ca(NO₃)₂ + 2 AgCl

mass, g 6.97 6.39 ?

MW ,g/mol 169.87 110.98 143.32

mol =m/MW 0.10 0.06 0.10

From the table above AgNO₃ is the limiting reagent and we will produce 0.10 mol AgCl which is a mass :

0.10 mol x 143.32 g/mol = 14.33 g

5 0

3 years ago

romeo is upset that he'll no longer be able yo see juliet, but this living creature will be able to see her, be near her, even f

Lyrx [107]

Answer:

beautiful and beautiful home on

8 0

3 years ago

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