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3 years ago

How do you find the atomic mass/mass number of an atom

1 answer:

3 0

You can find the mass number and the atomic number in the periodic table.

E.g. >>> Look at the periodic table, and find the oxygen (O):
the mass number: 15,9994u
the atomic number: 8

And find the magnesium (Mg):
the mass number: 24,3050u
the atomic number: 12

Etc.
:)

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What are the threats to coral reefs

spayn [35]

No answer choices?

Well, human destruction, pollution and overpopulation could all be threats to coral reefs.

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4 years ago

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Which characteristic is not common to outer planets? Question 3 options: They support rung systems They have no solid surface Th

Dominik [7]

Answer:

They have no solid surface.

Explanation:

Many outer planets are actually known as gas giants and don't contain much of a solid surface. hope this helped!

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3 years ago

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It takes 839./kJmol to break a carbon-carbon triple bond. Calculate the maximum wavelength of light for which a carbon-carbon tr

tresset_1 [31]

Answer:

The maximum wavelength of light for which a carbon-carbon triple bond could be broken by absorbing a single photon is 143 nm.

Explanation:

It takes 839 kJ/mol to break a carbon-carbon triple bond.

Energy required to break 1 mole of carbon-carbon triple bond = E = 839 kJ

E = 839 kJ/mol = 839,000 J/mol

Energy required to break 1 carbon-carbon triple bond = E'

$E'=\frac{ 839,000 J/mol}{N_A}=\frac{839,000 J}{6.022\times 10^{23} mol^{-1}}=1.393\times 10^{-18} J$

The energy require to single carbon-carbon triple bond will corresponds to wavelength which is required to break the bond.

$E'=\frac{hc}{\lambda }$ (Using planks equation)

$\lambda =\frac{6.626\times 10^{-34} Js\times 3\times 10^8 m/s}{1.393\times 10^{-18} J}$

$\lambda =1.427\times 10^{-7} m =142.7 nm = 143 nm$

$(1 m = 10^9 nm)$

The maximum wavelength of light for which a carbon-carbon triple bond could be broken by absorbing a single photon is 143 nm.

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4 years ago

How many total electrons and valence electrons are in the following? (two answers for each compound)

Ivenika [448]

Answer:

o2=-2

h20=2

Explanation:

.............

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3 years ago

How many grams of CaF2 would be needed to produce 1.12 moles of F2?

zlopas [31]

Step 1 : Write balanced chemical equation.

CaF₂ can be converted to F₂ in 2 steps. The reactions are mentioned below.

I] $CaF_{2} + H_{2} SO_{4} -------> 2HF + CaSO_{4}$

II] $2HF -------> H_{2} + F_{2}$

The final balanced equation for this reaction can be written as

$CaF_{2} + H_{2} SO_{4} ---------> CaSO_{4} + H_{2} + F_{2}$

Step 2: Find moles of CaF₂ Using balanced equation

We have 1.12 mol F₂

The mole ratio of CaF₂ and F₂ is 1:1

$1.12mol F_{2} * \frac{1molCaF_{2}}{1molF_{2}} = 1.12molCaF_{2}$

Step 3 : Calculate molar mass of CaF2.

Molar mass of CaF₂ can be calculated by adding atomic masses of Ca and F

Molar mass of CaF₂ = Ca + 2 (F)

Molar mass of CaF₂ = 40.08 + 18.998 = 78.08 g

Step 4 : Find grams of CaF₂

Grams of CaF₂ = $1.12molCaF_{2} *\frac{78.08gCaF_{2}}{1mol CaF_{2}}$

Grams of CaF₂ = 87.45 g

87.45 grams of CaF2 would be needed to produce 1.12 moles of F2.

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3 years ago

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