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3 years ago

During an experiment water was heated in a container covered with a glass lid. The following observations were recorded.

Chemistry

2 answers:

Hatshy [7]3 years ago

7 0

physical, even though it is boiling but the droplets is still water, water when boil was still water

Hitman42 [59]3 years ago

6 0

It is a physical change because it only changed states

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C3H8+3O2 = 3CO2+4H2O what is the enthalpy combustion

dezoksy [38]

Answer:

$\Delta H_{comb}=2043.85kJ/mol$

Explanation:

Hello there!

In this case, according to the given chemical reaction, it possible for us to set up the expression for the calculation of the enthalpy change as shown below:

$\Delta H_r=-\Delta H_{comb}=3\Delta _fH_{CO_2}+4\Delta _fH_{H_2O}-\Delta _fH_{C_3H_8}-3\Delta _fH_{O_2}$

Thus, given the values of the enthalpies of formation on the attached file, we obtain: $-\Delta H_{comb}=3(-393.5kJ/mol)+4(-241.8kJ/mol)-(-103.85kJ/mol)-3(0kJ/mol)\\\\-\Delta H_{comb}=-2043.85kJ/mol\\\\\Delta H_{comb}=2043.85kJ/mol$

Best regards!

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3 years ago

If a lake became too acidic, which of the following describes the best way that scientists could determine how to make the lake

masha68 [24]

The answer is ....................c

5 0

3 years ago

Describe how to do a flame test on a sample of a salt

Katen [24]

Answer:Hope this helps!

Explanation:

You can use a flame test to help identify the composition of a sample. The test is used to identify metal ions (and certain other ions) based on the characteristic emission spectrum of the elements. The test is performed by dipping a wire or wooden splint into a sample solution or coating it with the powdered metal salt. The color of a gas flame is observed as the sample is heated. If a wooden splint is used, it's necessary to wave the sample through the flame to avoid setting the wood on fire. The color of the flame is compared against the flame colors known to be associated with the metals.

4 0

3 years ago

Most Bic lighters hold 5.0ml of liquified butane (density = 0.60 g/ml). Calculate the minimum size container you would need to "

Hatshy [7]

Answer:

Volume of container = 0.0012 m³ or 1.2 L or 1200 ml

Explanation:

Volume of butane = 5.0 ml

density = 0.60 g/ml

Room temperature (T) = 293.15 K

Normal pressure (P) = 1 atm = 101,325 pa

Ideal gas constant (R) = 8.3145 J/mole.K)

volume of container V = ?

Solution

To find out the volume of container we use ideal gas equation

PV = nRT

P = pressure

V = volume

n = number of moles

R = gas constant

T = temperature

First we find out number of moles

As Mass = density × volume

mass of butane = 0.60 g/ml ×5.0 ml

mass of butane = 3 g

now find out number of moles (n)

n = mass / molar mass

n = 3 g / 58.12 g/mol

n = 0.05 mol

Now put all values in ideal gas equation

PV = nRt

V = nRT/P

V = (0.05 mol × 8.3145 J/mol.K × 293.15 K) ÷ 101,325 pa

V = 121.87 ÷ 101,325 pa

V = 0.0012 m³ OR 1.2 L OR 1200 ml

8 0

3 years ago

How might you think it is possible to convert from moles to particles or grams to particles?

nevsk [136]

Explanation:

To convert moles to particles or grams to particles, let us have a firm understanding of what a mole is.

A mole is the unit of measuring quantity of particles.

It is the amount of substance that contains the Avogadro's number of particles.

The particle can be atoms, molecules, formula units, electrons, protons, neutrons, etc.

So, to convert from moles to particles;

1 mole of a substance contains 6.02 x 10²³ particles

To convert from grams to particles;

First convert to moles;

number of moles = $\frac{mass}{molar mass}$

So, 1 mole of a substance contains 6.02 x 10²³ particles

4 0

2 years ago