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3 years ago

Hi! I need help with this question, if it is possible, please answer immediately.

Chemistry

1 answer:

Dennis_Churaev [7]3 years ago

6 0

Answer:

Explanation:

The paper clip allows elictricity to pass, unlike the eraser or paper

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How does the environment influence natural selection?

Nonamiya [84]

The environment affects natural selection. Speices need to adapt to changes in environmnet. The weaker organisms which fail to adapt to environment perish while the stronger ones who adapt to the environment survive. This is how environment affects natural selection.

7 0

3 years ago

a 0.555 g sample of mayonnase was burned in excess oxygen inside a bomb calorimeter with a total heat capacity (bomb and water)

Fofino [41]

Answer:

$Dietary\ Calories=65.6kcal$

Explanation:

Hello!

In this case, since we can see that the heat released by the combustion of the mayonnaise is absorbed by the bomb calorimeter and water, we can set up the following equation:

$m_{mayonnaise}q_{mayonnaise}=C\Delta T$

Whereas q for mayonnaise stands for the heat due to its usage; thus, we plug in to obtain:

$q_{mayonnaise}=\frac{5.20kJ/\°C*2.93\°C}{0.555g} \\\\q_{mayonnaise}=27.45\frac{kJ}{g}$

Now, if 10.0 g are eaten, the energy provided by it turns out:

$E_{mayonnaise}=27.45kJ/g*10.0g\\\\E_{mayonnaise}=274.5kJ$

And we need that value in dietary calories, 1 kcal:

$Dietary\ Calories=274.52kJ*\frac{1kcal}{4.184kJ}\\\\ Dietary\ Calories=65.6kcal$

Best regards!

4 0

3 years ago

Colton has an ice cube that has a mass of 4 grams. He places it in a sealed container and then puts it in the microwave on high.

Bas_tet [7]

I believe the answer is D.

The reason is because mass cannot be destroyed. All the mass can really do is become more of less dense.

5 0

3 years ago

A 50.00-mL solution of 0.0350 M aniline ( Kb = 3.8 × 10–10) is titrated with a 0.0113 M solution of hydrochloric acid as the tit

nexus9112 [7]

Answer:

pH = 3.70

Explanation:

Moles of aniline in solution are:

0.0500L × (0.0350mol / 1L) = 1.750x10⁻³ mol aniline

Aniline is in equilibrium with water, thus:

C₆H₅NH₂ + H₂O ⇄ C₆H₅NH₃⁺ + OH⁻ Kb = 3.8x10⁻¹⁰

HCl reacts with aniline thus:

HCl + C₆H₅NH₂ → C₆H₅NH₃⁺ + Cl⁻

At equivalence point, all aniline reacts producing C₆H₅NH₃⁺. C₆H₅NH₃⁺ has its own equilibrium with water thus:

C₆H₅NH₃⁺(aq) + H₂O(l) ⇄ C₆H₅NH₂(aq) + H₃O⁺(aq)

Where Ka is defined as:

Ka = [C₆H₅NH₂] [H₃O⁺] / [C₆H₅NH₃⁺] = Kw / Kb = 1.0x10⁻¹⁴ / 3.8x10⁻¹⁰ = 2.63x10⁻⁵ (1)

As all aniline reacts producing C₆H₅NH₃⁺, moles in equilibrium are:

[C₆H₅NH₃⁺] = 1.750x10⁻³ mol - X

[C₆H₅NH₂] = X

[H₃O⁺] = X

Replacing in (1):

2.63x10⁻⁵ = [X] [X] / [1.750x10⁻³ mol - X]

4.6x10⁻⁸ - 2.63x10⁻⁵X = X²

0 = X² + 2.63x10⁻⁵X - 4.6x10⁻⁸

Solving for X:

X = -2.3x10⁻⁴ → False answer, there is no negative concentrations

X = 2.0x10⁻⁴ → Right answer

As [H₃O⁺] = X, [H₃O⁺] = 2.0x10⁻⁴.

Now, pH = -log[H₃O⁺]. Thus, pH at equivalence point is:

pH = 3.70

7 0

3 years ago

Round to 4 significant figures. 2.3581 x 103 [?] x 103

Masja [62]

Answer:

2.358

Explanation:

6 0

3 years ago