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2 years ago

15

An alien civilization has different names and symbols for six elements. Place each element in the correct location in the period

ic table.

2 answers:

olga2289 [7]2 years ago

5 0

Answer:

The picture

Explanation:

You just have to count the number of valence electrons and place the unknown elements on the periodic table according to their atomic number.

Margarita [4]2 years ago

3 0

Answer:

why whould I know that!!??

Explanation:

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There is a gas at 780 mm of Hg, in a volume of 5 liters and a temperature of 37 C, the volume is changed to 5.5 liters and the

HACTEHA [7]

Answer:

32.8 C

Explanation:

- Use combined gas law formula and rearrange.

- Hope that helped! Please let me know if you need further explanation.

6 0

3 years ago

Enter your answer in the provided box. Calculate the number of moles of CrCl, that could be produced from 49.4 g Cr202 according

Mrrafil [7]

Answer:

0.4694 moles of CrCl₃

Explanation:

The balanced equation is:

Cr₂O₃(s) + 3CCl₄(l) → 2CrCl₃(s) + 3COCl₂(aq)

The stoichiometry of the equation is how much moles of the substances must react to form the products, and it's represented by the coefficients of the balanced equation. So, 1 mol of Cr₂O₃ must react with 3 moles of CCl₄ to form 2 moles of CrCl₃ and 3 moles of COCl₂.

The stoichiometry calculus must be on a moles basis. The compounds of interest are Cr₂O₃ and CrCl₃. The molar masses of the elements are:

MCr = 52 g/mol

MCl = 35.5 g/mol

MO = 16 g/mol

So, the molar mass of the Cr₂O₃ is = 2x52 + 3x35.5 = 210.5 g/mol.

The number of moles is the mass divided by the molar mass, so:

n = 49.4/210.5 = 0.2347 mol of Cr₂O₃.

For the stoichiometry:

1 mol of Cr₂O₃ ------------------- 2 moles of CrCl₃

0.2347 mol of Cr₂O₃----------- x

By a simple direct three rule:

x = 0.4694 moles of CrCl₃

6 0

2 years ago

6. What is true about Calcium (Ca)?

sasho [114]

Answer:

C. naturally uncombined with other elements.

Explanation: Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air.

8 0

2 years ago

Materials: • One disposable plastic cup • One disposable plastic spoon (plastic fork or knife may be used instead) • Thermometer

Leya [2.2K]

I'm not sure what the question is, this is a lab proecdure

4 0

3 years ago

Balance the following redox equation using the smallest integers possible and select the correct coefficient for the hydrogen su

goldfiish [28.3K]

Answer:

Coefficient of $HSO_{3}^{-}$ is 5

Explanation:

Oxidation: $MnO_{4}^{-}(aq)\rightarrow Mn^{2+}(aq)$

Balance O and H in acidic medium: $MnO_{4}^{-}(aq)+8H^{+}(aq)\rightarrow Mn^{2+}(aq)+4H_{2}O(l)$
Balance charge : $MnO_{4}^{-}(aq)+8H^{+}(aq)+5e^{-}\rightarrow Mn^{2+}(aq)+4H_{2}O(l)$ .............(1)

Reduction: $HSO_{3}^{-}\rightarrow SO_{4}^{2-}$

Balance O and H in acidic medium : $HSO_{3}^{-}(aq)+H_{2}O(l)\rightarrow SO_{4}^{2-}(aq)+3H^{+}(aq)$
Balance charge : $HSO_{3}^{-}(aq)+H_{2}O(l)-2e^{-}\rightarrow SO_{4}^{2-}(aq)+3H^{+}(aq)$ ..............(2)

$[2\times eq(1)]+[5\times eq(2)]$ -

Balanced equation: $2MnO_{4}^{-}(aq)+5HSO_{3}^{-}(aq)+H^{+}(aq)\rightarrow 2Mn^{2+}(aq)+5SO_{4}^{2-}(aq)+3H_{2}O(l)$

Coefficient of $HSO_{3}^{-}$ is 5

8 0

2 years ago