Which atoms are most likely to form covalent bonds?

Copper(l) sulfide can react with oxygen to produce copper metal by the reaction cu2s + o2 => 2cu + so2. if 5.00 g of cu2s is

valentina_108 [34]

To answer this problem, we write first the stoichiometric equation. Thus we have,

Cu2S + O2 => 2Cu + SO2

Next, we check if the equation is balanced or not.

(left) (right)
2 Cu = 2 Cu
1 S = 1 S
2 O = 2 O

So the stoichiometric equation is balanced, let's proceed in solving the theoretical yield of Cu given 5 g of Cu2S.

First, we solve for Cu2S in moles,
5 g Cu2S x 1 mol Cu2S = 0.0314 mol Cu2S
159.16 g Cu2s

Secondly, convert moles of Cu2S to moles Cu. Note for every mole of Cu2S we get 2 moles of Cu. Thus,

0.0314 mo Cu2S x 2 mol Cu = 0.0628 mole Cu
 1 mol Cu2S

Lastly, we convert mole Cu to g Cu via multiplying by Cu's MW.

0.0628 mole Cu x 63.546 g Cu = 3.99 g Cu or 4 g Cu
 1 mole Cu

ANSWER: 4 g Cu

4 0

3 years ago

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When matter and energy change forms within a closed system, A. the total amount of matter changes, but the total amount of energ

Nadya [2.5K]

Answer:

Option D. The total amount of both matter and energy does not change.

Explanation:

From Law of conservation of energy and Einstein's mass-energy relation, we know that, energy neither is formed not is destroyed. It converts from one form to another. Einstein's mass-energy relation: E = mc². It means, Matter is a form of energy i.e. matter holds energy equivalent to product of its mass and square of speed of light. Matter and energy can change forms but the total amount does not change in a closed system. Thus, correct option is D.

8 0

3 years ago

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Identify six elements common to organic compounds.

valentinak56 [21]

Carbon and hydrogen are present in all
nitrogen is common
sulphur in proteins is common
oxygen is common in ethanoic acids
phosphorus is common for phosphate sugars

hope that helps

4 0

3 years ago

What is the ph level of water?

zloy xaker [14]

For pure water the PH level is 7

7 0

3 years ago

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8. Classify each of the following changes as physical or chemical: (a) coal burning (b) ice melting (c) mixing chocolate syrup w

IrinaK [193]

Answer:

(a) coal burning: chemical change

(b) ice melting: physical change

(c) mixing chocolate syrup with milk : physical change

(d) explosion of a firecracker: chemical change

(e) magnetizing of a screwdriver: physical change

Explanation:

A physical change changes the physical form or the appearance or the property of the substance, but the chemical composition of the matter remains the same. Such a change is reversible in nature.

Whereas; a chemical change involves a chemical reaction, resulting in the change in the chemical composition of the matter. A chemical change results in the formation of a new substance and is generally irreversible in nature.

(a) coal burning: It is a chemical change because the combustion of coal changes its chemical composition. When coal (carbon) is burned carbon dioxide is released. Irreversible in nature

$C(s) + O_{2}(g)\rightarrow CO_{2}(g)$

(b) ice melting: It is a physical change because ice the solid phase of water melts to get converted to the liquid phase of water only and no change in the chemical composition is seen.

$H_{2}O(s) \overset{\Delta }{\rightarrow} H_{2}O(l)$

(c) mixing chocolate syrup with milk : It is a physical change because on dissolving chocolate syrup in milk, only the color of the milk changes, therefore there is change in the property. As, it involves mixing of two miscible liquids and does not involve any change in the chemical composition of either of the two liquids.

(d) explosion of a firecracker: it is a chemical process, as it involves combustion of an explosive material to produce carbon dioxide, carbon monoxide and water vapour. It is a chemical change because it involves change in the chemical composition. Irreversible in nature

(e) magnetizing of a screwdriver: It is physical change because on magnetization only the magnetic property of the screwdriver changes AND there is no change in the chemical composition of the matter.

6 0

3 years ago