I have 3 questions i'm curious about *SCIENCE*

In a test of an automobile engine 1.00 L of octane (702 g) is burned, but only 1.84 kg of carbon dioxide is produced. What is th

Reptile [31]

Answer:

The % yield of CO2 is 85.05 %

Explanation:

Step 1: Data given

Mass of octane = 702 grams

Molar mass octane = 114.23 g/mol

Mass CO2 =1.84 kg = 1840 grams

Molar mass of CO2

Step 2: The balanced equation

2C8H18 + 25O2 → 16CO2 + 18H2O

Step 3: Calculate moles of octane

Moles octane = mass octane / molar mass octane

Moles octane = 702.0 grams / 114.23 g/mol

Moles octane = 6.145 moles

Step 4: Calculate moles of CO2

For 2 moles octane we need 25 moles O2 to produce 16 moles CO2 and 18 moles H2O

For 6.145 moles octane we'll have 8*6.145 moles =49.16 moles

Step 5: Calculate mass of CO2

Mass CO2 = moles CO2 * molar mass CO2

Mass CO2 = 49.16 moles * 44.01 g/mol

Mass CO2 = 2163.5 grams

Step 6: Calculate % yield of carbon dioxide

% yield = (actual yield / theoretical yield)*100%

% yield = (1840/2163.5)*100%

% yield = 85.05 %

The % yield of CO2 is 85.05 %

4 0

3 years ago

A) explain why caesium is more reactive than potassium.

Kamila [148]

Answer:

Explanation:

(a) Firstly, caesium abd potassium are both in Group 1 of the periodic table. Group 1 metals (also called alkali metals) are the most reactive metals of the periodic table. Caesium is more reactive than Potassium because it has a higher electropositivity than Potassium. Electropositivity is the tendency of a metal to donate electron(s) to form a cation. Electropositivity increases down the group; this is because it is easier for atoms to loose electrons on the outermost shell that are far away from the central nucleus as against atoms whose outermost electrons are closer to the central nucleus. <u>Thus, the more "bulky" an atom is, the farther it's outermost electrons (valence electrons) get from the central nucleus and the easier it is to lose the outermost electron(s). And the easier it is for the valence electron(s) to be removed, the more reactive the atom would be and vice-versa.</u>

Caesium is more reactive than potassium because it is more bulky than potassium, with an atomic number of 55, while potassium has an atomic number of 19.

NOTE: The closer an electron is to the nucleus, the more difficult it is to be removed from it's shell.

(b) i. Formula for Caesium Nitrate:

Symbol for Caesium is Cs and Nitrate is NO₃⁻.

Cs⁺ + NO₃⁻ ↔ CsNO₃

Formula for Caesium Nitrate is CsNO₃

ii. Formula for Caesium sulphate

Symbol for caesium is Cs and Sulphate is SO₄²⁻

Cs⁺ + SO₄²⁻ ↔ Cs₂SO₄

Formula for Caesium sulphate is Cs₂SO₄

NOTE: When writing the formulae, the charges would be exchanged to form the subscript as seen on the product sides above.

7 0

2 years ago

PLEASEEEE HELP MEEEEE

fiasKO [112]

Answer:

3.82 x 10²¹ molecules As₂O₃

Explanation:

To find the amount of molecules arsenic (III) oxide (As₂O₃), you need to (1) convert kg to lbs, then (2) convert g As₂O₃ to moles As₂O₃ (via molar mass), and then (3) convert moles to molecules (via Avogadro's number).

1 kilogram = 2.2 lb

Molar Mass (As₂O₃): 2(74.992 g/mol) + 3(15.998 g/mol)

Molar Mass (As₂O₃): 197.978 g/mol

Avogadro's Number:

6.022 x 10²³ molecules = 1 mole

0.0146 g As₂O₃ 1 kg 189 lb
------------------------ x --------------- x ------------------ x ................
1 kg 2.2 lb

1 mole 6.022 x 10²³ molecules
x ------------------ x --------------------------------------- = 3.82 x 10²¹ molecules As₂O₃
197.978 g 1 mole

6 0

2 years ago

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What is the total charge of the nucleus of a carbon atom?<br> (1) –6 (3) +6<br> (2) 0 (4) +12

NeX [460]

Carbon atomic number ⇒ 6
Carbon mass number ⇒ 12.

Carbon atomic number - Carbon mass number = number of neutrons.
12 - 6 = 6 neutrons.

Proton charge ⇒ +1

The total charge of the nucleus of a carbon atom ⇒⇒⇒ +6.

So the naswer is (3) +6

3 0

3 years ago

In what era did reptiles become increasingly dominant?

emmainna [20.7K]

Correct answer: B. Paleozoic. I took the test and it was right.

6 0

3 years ago

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