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3 years ago

Help pls I will give brainliest!

Chemistry

1 answer:

yKpoI14uk [10]3 years ago

7 0

Answer:

The answer is D, I would type it out but it is to long and I'm kind of lazy, but anyways! Your answer is D

Hope This Helps!

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Why are things like magic, astrology and psychic predictions not considered science?

romanna [79]

Things such as magic, astrology, and psychic predictions are not considered science because there is not enough empirical and circumstantial evidence to back up the hypotheses. I hope this helps, and please mark as Brainliest answer!

3 0

3 years ago

if you have 1000g of radioactive waste with a half life of 50 million years what amount will you have left after 200 million yea

Lina20 [59]

You will have 62.5 grams

1000g at 0 years
500g at 50mill
250g at 100mill
125g at 150 mil
62.5g at 200mill

6 0

3 years ago

Estrone, which contains only carbon, hydrogen, and oxygen, is a female sexual hormone that occurs in the urine of pregnant women

timofeeve [1]

Answer:

The formula of Estrone = $C_{18}H_{22}O_2$

Explanation:

Mass of water obtained = 1.388 g

Molar mass of water = 18 g/mol

Moles of $H_2O$ = 1.388 g /18 g/mol = 0.07711 moles

2 moles of hydrogen atoms are present in 1 mole of water. So,

Moles of H = 2 x 0.07711 = 0.1542 moles

Molar mass of H atom = 1.008 g/mol

Mass of H in molecule = 0.1542 x 1.008 = 0.1555 g

Mass of carbon dioxide obtained = 5.543 g

Molar mass of carbon dioxide = 44.01 g/mol

Moles of $CO_2$ = 5.543 g /44.01 g/mol = 0.126 moles

1 mole of carbon atoms are present in 1 mole of carbon dioxide. So,

Moles of C = 0.126 moles

Molar mass of C atom = 12.0107 g/mol

Mass of C in molecule = 0.126 x 12.0107 = 1.5133 g

Given that the Estrone only contains hydrogen, oxygen and carbon. So,

Mass of O in the sample = Total mass - Mass of C - Mass of H

Mass of the sample = 1.893 g

Mass of O in sample = 1.893 - 1.5133 - 0.1555 = 0.2242 g

Molar mass of O = 15.999 g/mol

Moles of O = 0.2242 / 15.999 = 0.01401 moles

Taking the simplest ratio for H, O and C as:

0.1542 : 0.01401 : 0.126

= 11 :1 : 9

The empirical formula is = $C_9H_{11}O$

Molecular formulas is the actual number of atoms of each element in the compound while empirical formulas is the simplest or reduced ratio of the elements in the compound.

Thus,

Molecular mass = n × Empirical mass

Where, n is any positive number from 1, 2, 3...

Mass from the Empirical formula = 9×12 + 11×1 + 16= 135 g/mol

Given, Molar mass = 270.36 g/mol

So,

Molecular mass = n × Empirical mass

270.36 = n × 135

⇒ n = 2

The formula of Estrone = $C_{18}H_{22}O_2$

7 0

3 years ago

The combustion of pentane, C5H12, occurs via the reaction

ValentinkaMS [17]

The heat of a chemical reaction (change of enthalý) may be calcualted as the heat of formation of the products less the heat of formation of the reactants.

Then, for the given equation, the total heat of the combustion of pentnae is:

ΔH°f = 5* ΔH°f CO2(g) + 6ΔH°f H2O(g) - ΔH°f C5H12(g) - 8ΔH°f O2(g)

The standard heat of formation of O2(g) is zero because that is its natural state.

Now you can replace in the equation the values given:

ΔH° = 5*(-393.5 kJ/mol) + 6*(-241.8kj/mol) - (-35.1kJ/mol) - 0

ΔH° = -3,383.2 kJ/mol

Then, the heat of the combustion of pentane is -3,383.2 kj/mol

7 0

3 years ago

ACTIVITY 2.: MYSTERY WORD

Bess [88]

Answer:

1.transverse waves

2.mechanical waves

3.longitudal waves

4.electromagnetic waves

6 0

3 years ago