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Vedmedyk [2.9K]
3 years ago
7

Which is the first element in the periodic table to have an electron configuration in the 4th energy level?

Chemistry
2 answers:
Tju [1.3M]3 years ago
7 0
The answer is potassium:)
solong [7]3 years ago
4 0

The answer is potassium .......

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How do you make a model of something you cannot see?
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You have to imagine it
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2 years ago
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A 3.4 g sample of an unknown monoprotic organic acid composed of C,H, and O is burned in air to produce 8.58 grams of carbon dio
Pavlova-9 [17]

Answer:

C_7H_6O_2

Explanation:

Hello there!

In this case, we can divide the problem in three stages: (1) determine the empirical formula with the combustion analysis, (2) compute the molar mass of acid via the moles of the acid in the neutralization and (3) determine the molecular formula.

(1) In this case, since 8.58 g of carbon dioxide are released, we can first compute the moles of carbon in the compound:

n_C=8.58gCO_2*\frac{1molCO_2}{44.01gCO_2}*\frac{1molC}{1molCO_2}=0.195molC

And the moles of hydrogen due to the produced 1.50 grams of water:

n_H=1.50gH_2O*\frac{1molH_2O}{18.02gH_2O}*\frac{2molH}{1molH_2O}  =0.166molH

Next, to compute the mass and moles of oxygen, we need to use the initial 3.4 g of the acid:

m_O=3.4g-0.195molC*\frac{12.01gC}{1molC}-0.166molH*\frac{1.01gH}{1molH} =0.89gO\\\\n_O=0.89gO*\frac{1molO}{16.0gO}=0.0556molO

Thus, the subscripts in the empirical formula are:

C=\frac{0.195}{0.0556}=3.5 \\\\H=\frac{0.166}{0.0556}=3\\\\O=\frac{0.0556}{0.0556}=1\\\\C_7H_6O_2

As they cannot be fractions.

(2) In this case, since the acid is monoprotic, we can compute the moles by multiplying the concentration and volume of KOH:

n_{KOH}=0.279L*0.1mol/L\\\\n_{KOH}=0.0279mol

Which are equal to the moles of the acid:

n_{acid}=0.0279mol

And the molar mass:

MM_{acid}=\frac{3.4g}{0.0279mol} =121.86g/mol

(3) Finally, since the molar mass of the empirical formula is:

7*12.01 + 6*1.01 + 2*16.00 = 122.13 g/mol

Thus, since the ratio of molar masses is 122.86/122.13 = 1, we infer that the empirical formula equals the molecular one:

C_7H_6O_2

Best regards!

8 0
3 years ago
2. Which energy source is considered a non-renewable resource?
Keith_Richards [23]

Answer:

The answer is D

Explanation:

Although natural processes continually form fossil fuels, such fuels are generally classified as non-renewable resources because they take millions of years to form and the known viable reserves are being depleted much faster than new ones are being made. ... The use of fossil fuels raises serious environmental concerns.

BRAINLIEST PLZ

8 0
3 years ago
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A 2.5 g sample of french fries is placed in a calorimeter with 500.0 g of water at an initial temperature of 21 °C. After combus
SIZIF [17.4K]
Q=m°C<span>ΔT
=(500g) x (1 cal/g.</span>°C) x (48°C-21°C) = 13500 cal
13500 cal / 1000 = 13.5 kcal

<span>"What is the caloric value (kcal/g) of the french fries?"
13.5 kcal/ 2.5 g = 5.4 kcal/g</span>
8 0
3 years ago
Gas and oxygen gas are the _______.
stiv31 [10]

i think it is Synthesis Reaction because in a synthesis reaction one or more simple substances combine to form a more complex substance.

If there is two or more reactions yilding one product is another way to identify a synthesis reaction.

For the chemical equation for this synthesis reaction really looks like:

reactant +reactant = product


if im wrong correct me but have a blessed day/night

=)


4 0
3 years ago
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