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3 years ago

Which statement accurately compares the trends in atomic number and atomic mass in the periodic table

Chemistry

2 answers:

Tresset [83]3 years ago

6 0

Answer: is C

Explanation:

Both the atomic mass and the atomic number increase from left to right

andrew11 [14]3 years ago

3 0

Answer:

The answer is number 3

Explanation:

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The solubility of oxygen gas in water at 40 ∘c is 1.0 mmol/l of solution. What is this concentration in units of mole fraction?

juin [17]

The formula for mole fraction is:

$mole fraction of solute = \frac{number of moles of solute}{total number of moles of solution}$ -(1)

The solubility of oxygen gas = 1.0 mmol/L (given)

1.0 mmol/L means 1.0 mmol are present in 1 L.

Converting mmol to mol:

$1.00 mmol\times \frac{1 mol}{1000 mmol} = 0.001 mol$

So, moles of oxygen = 0.001 mol

For moles of water:

1 L of water = 1000 mL of water

Since, the density of water is 1.0 g/mL.

$Density = \frac{mass}{volume}$

$Mass = 1.0 g/ml\times 1000 mL = 1000 g$

So, the mass of water is 1000 g.

Molar mass of water = 18 g/mol.

Number of moles of water = $\frac{1000 g}{18 g/mol} = 55.55 mol$

Substituting the values in formula (1):

$mole fraction = \frac{0.001}{55.55+0.001}$

$mole fraction = 1.8\times 10^{-5}$

Hence, the mole fraction is $1.8\times 10^{-5}$ .

7 0

3 years ago

Ammonium perchlorate NH4ClO4 is a powerful solid rocket fuel, used in the Space Shuttle boosters. It decomposes into nitrogen N2

patriot [66]

Answer: 0.055 moles of $O_2$ are produced by the reaction of 0.055 mol of ammonium perchlorate.

Explanation:

The balanced chemical reaction for decomposition of ammonium perchlorate is:

$2NH_4ClO_4\rightarrow N_2+Cl_2+2O_2+4H_2O$

According to stoichiometry :

2 moles of $NH_4ClO_4$ produce = 2 moles of $O_2$

Thus 0.055 moles of $NH_4ClO_4$ will produce = $\frac{2}{2}\times 0.055=0.055moles$ of $O_2$

Thus 0.055 moles of $O_2$ are produced by the reaction of 0.055mol of ammonium perchlorate.

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3 years ago

PLEASE HELP A HOMIIE

Allushta [10]

Answer:

Its the first one. The cells are arranged for structure.

Explanation:

Animal cells do not need to maintain a shape since out bodies do it for us. Plant cells need something for structure.

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3 years ago

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12345 [234]

Explanation:

a) 3Pb(NO3)2 + Al2(SO4)3 ---> 3PbSO4 + 2Al(NO3)3

Double displacement

b) 2Cl2 + 3O2 ---> 2Cl2O3

Synthesis

c) 2Fe2O3 + 3C ---> 4Fe + 3CO2

single displacement

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3 years ago

Why do you think there are different stars in each nighttime section of the artifact?

chubhunter [2.5K]

Answer:

The sky looks different in each nighttime section of the artifact because the artifact sections represent different seasons. ... Different constellations are visible on different nights throughout the year because of the earth's orbit. The Earth orbits around the sun. A full orbit is 365 days or one year.

Explanation:

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3 years ago