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3 years ago

Help ASAP 15 Points

Chemistry

1 answer:

Lubov Fominskaja [6]3 years ago

8 0

Answer:

The independent variable of an experiment is the one that is intentionally changed or manipulated to see the results of changing said variable.

We are told that in each different group, the amount of caffeine that is given to the dog's changes - in the control group, they get no caffeine, in the 2nd group, they get 10 mg of caffeine each, and in the 3rd group, they get 50 mg of caffeine each.

Therefore, since the amount of caffeine that is given to the dogs is the only variable that is being manipulated, this is the independent variable.

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Water, H2O, is classified as a(n) A) colloid. B) compound. C) element. D) mixture.

MA_775_DIABLO [31]

The answer is <span>B) compound. hope it helps~!!!!!!!!!!!!!!!!!!:)</span>

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4 years ago

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If there are 0.064g of theobromine in a 43g chocolate bar, how many moles of theobromine are there?

Sever21 [200]

Answer: $3.5\times 10^{-4}$

Explanation:

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}$

Given mass of theobromine $(C_7H_8N_4O_2)$ = 0.064 g

Molar mass of theobromine $(C_7H_8N_4O_2)=12\times 7+1\times 8+14\times 4+16\times 2=180 g$

$\text{Number of moles}=\frac{0.064g}{180g/mol}=3.5\times 10^{-4}moles$

5 0

3 years ago

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Calculate the amount of CO2 (in kg) released when 1 kg of coal is burned. Assume that carbon content of the coal is 50% by mass.

Delvig [45]

Answer:

1.8321 kg

Explanation:

The given 1 kg of coal contains 50% of the carbon atom by mass. Thus, mass of carbon in coal is $\frac {50}{100}\times 1\ kg=0.5\ kg$

Also, 1 kg = 1000 g

So, mass of carbon = 500 g

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Molar mass of carbon = 12.0107 g/mol

Moles of methanol = 500 g / 12.0107 g/mol = 41.6295 moles

Considering the reaction:

$C+O_2\rightarrow CO_2$

From the reaction,

1 mole of C react to form 1 mole of $CO_2$

So,

41.6295 moles of C react to form 41.6295 moles of $CO_2$

Moles of $CO_2$ = 41.6295 moles

Molar mass of $CO_2$ = 44.01 g/mol

So, Mass = Moles × Molar mass = 41.6295 moles × 44.01 g/mol = 1832.1143 g

Also, 1g = 0.001 kg

<u>So, amount of $CO_2$ released = 1.8321 kg</u>

4 0

3 years ago

Bauxite must go through two processes to produce aluminum metal. The yield of the Bayer process, which extracts aluminum oxide f

Mashcka [7]

The yield of aluminium obtained from 1 m^3 of bauxite is 419810 g

<h3>What is a Percent yield</h3>

A percent yield of a substance measures the amount of the substance actually obtained as a percentage ratio of expected yield.

Percent yield = actual yield / expected yield × 100%

<h3>How to calculate the mass of aluminium obtained from bauxite </h3>

From the data given:

40 % of the bauxite is converted to aluminium oxide.

Volume of bauxite = 1 m^3

40 % of 1 m^3 = 0.4 m^3

volume of aluminium oxide = 0.4 m^3

density of aluminium oxide = 3965 kg/m^3

Using mass = density × volume

mass of aluminium oxide = 0.4 × 3965 kg

mass of aluminium oxide = 1586 kg

Formula of aluminium oxide is Al203

molar mass of aluminium oxide = 102 g

percentage mass of aluminium in one mole of aluminium oxide = mass of aluminium / mass of aluminium oxide × 100 %

Percentage mass of aluminium in aluminium oxide = 54/102 × 100

Percentage mass of aluminium in aluminium oxide = 52.94 %

Expected mass of aluminium from aluminium oxide = 52.94 × 1586

Expected mass of aluminium = 839.62 kg

Actual yield = 40 % × 839.62

Actual yield of aluminium = 419.81 kg

mass of aluminium in grams = 419810 g

Therefore, mass of aluminium obtained from 1 m^3 of bauxite is 419810 g

Learn more about percent yield at: brainly.com/question/8638404

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3 years ago

The boiling points of halogens increase in the following order F2 a. ion-dipole<br> b. hydrogen-bonding<br> c. ion-ion<br> d. di

Viefleur [7K]

In order for the molecule to change phase from liquid to gas and evaporates, it needs to overcome the force from other molecules around it. as the force bigger evaporation gets harder. so e has the highest force and higher boiling point.

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3 years ago