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Makovka662 [10]
3 years ago
15

Can anyone help me? it's chemistry​

Chemistry
1 answer:
ivann1987 [24]3 years ago
8 0
There is no any questions???
You might be interested in
Which are balanced and which are unbalanced?
erica [24]

A. is balanced

B. is not balanced

C. is not balanced

3 0
3 years ago
When 1.0 mole of MgSO4 is dissolved in water contained in a calorimeter, the temperature of the water and dissolved ions increas
KatRina [158]

Answer: negative , from , to , exothermic

Explanation:

An endothermic reaction is a type of chemical reaction in which energy is absorbed from the surrounding. The temperature of the surrounding decreases.

An Exothermic reaction is a type of chemical reaction in which energy is released into the surrounding. The temperature of the surrounding increases.

Endothermic reactions are those in which heat is absorbed by the system from the surroundings and exothermic reactions are those in which heat is released by the system to the surroundings. \Delta H  for Endothermic reaction is positive and  

As on dissolution of salt, the temperature of water increases, the heat has been released from system into surroundings and thus \Delta H is negative.

4 0
3 years ago
An unknown compound contains 75.69% carbon, 8.80% hydrogen, and 15.51% oxygen by mass. A mass spectrometry analysis reveals that
tiny-mole [99]

Answer:

Molecular formula is C₂₆H₃₆O₄

Explanation:

The compound is 75.69 % C, 8.80 % H and 15.51 % O. This data means, that in 100 g of compound we have 75.69 g, 15.51 g and 8.80 g of, C, O and H, respectively. We know the molar mass of the compound, so we can work to solve the moles of each element.

In 100 g of compound we have 75.69 g C, 15.51 g O and 8.80 g H

In 412 g of compound we would have:

(412 . 75.69) / 100 = 311.8 of C

(412 . 15.51) / 100 = 63.9 g of O

(412 . 8.80) / 100 = 36.2 g of H

Now, we can determine the moles of each, that are contained in 1 mol of compound.

312 g / 12 g/mol 26 C

64 g / 16 g/mol = 4 O

36 g / 1 g/mol = 36 H

Molecular formula is C₂₆H₃₆O₄

4 0
3 years ago
Express the concentration of a 0.0390 M aqueous solution of fluoride, F − , in mass percentage and in parts per million (ppm). A
Vadim26 [7]

Answer:

Mass percentage → 0.074 %

[F⁻] = 741 ppm

Explanation:

Aqueous solution of flouride → [F⁻] = 0.0390 M

It means that in 1L of solution, we have 0.0390 moles of F⁻

We need the mass of solution and the mass of 0.0390 moles of F⁻

Mass of solution can be determined by density:

1g/mL = Mass of solution / 1000 mL

Note: 1L = 1000mL

Mass of solution: 1000 g

Moles of F⁻ → 0.0390 moles . 19g /1 mol = 0.741 g

Mass percentage → (Mass of solute / Mass of solution) . 100

(0.741 g / 1000 g) . 100 = 0.074 %

Ppm = mass of solute . 10⁶ / mass of solution (mg/kg)

0.741 g . 1000 mg/1g = 741 mg

1000 g . 1 kg/1000 g = 1kg

741 mg/1kg = 741 ppm

5 0
3 years ago
It's fine if u cant answer all of them, just heeelp pls
Katena32 [7]
The answer is B but iam not sure about the answer
6 0
3 years ago
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