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AVprozaik [17]
3 years ago
9

When was copper discovered?​

Chemistry
1 answer:
Vesna [10]3 years ago
3 0

Answer:

9000 BC

Explanation:

Although various copper tools and decorative items dating back as early as 9000 BCE have been discovered, archaeological evidence suggests that it was the early Mesopotamians who, around 5000 to 6000 years ago, were the first to fully harness the ability to extract and work with copper.

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Describe one way that grazing animals, such as bison or cattle, help to maintain grassland ecosystems.
My name is Ann [436]

Answer:

They fertilize the land and help with overgrowth.

Explanation:

5 0
3 years ago
What is the concentration of chloride in a solution made with 0.808 grams of CaCl2 and 250.0 ml of water.?
densk [106]

Answer:

0.0584 M

Explanation:

From the question given above, the following data were obtained:

Mass of CaCl₂ = 0.808 g

Volume of water = 250 mL

Concentration of chloride =?

Next, we shall determine the number of mole in 0.808 g of CaCl₂. This can be obtained as follow:

Mass of CaCl₂ = 0.808 g

Molar mass of CaCl₂ = 40 + (35.5 × 2)

= 40 + 71

= 111 g/mol

Mole of CaCl₂ =?

Mole = mass / Molar mass

Mole of CaCl₂ = 0.808 / 111

Mole of CaCl₂ = 0.0073 mole

Next, we shall convert 250 mL to L. This can be obtained as follow:

1000 mL = 1 L

Therefore,

250 mL = 250 mL × 1 L / 1000 mL

250 mL = 0.25 L

Next, we shall determine the molarity of CaCl₂. This can be obtained as follow:

Mole of CaCl₂ = 0.0073 mole

Volume of water = 0.25 L

Molarity of CaCl₂ =?

Molarity = mole /Volume

Molarity of CaCl₂ = 0.0073 / 0.25

Molarity of CaCl₂ = 0.0292 M

Finally, we shall determine the concentration of the chloride as illustrated below:

CaCl₂ <=> Ca²⁺ + 2Cl¯

From the equation above,

1 mole of CaCl₂ produced 2 mole of Cl¯.

Therefore, 0.0292 M CaCl₂ will produce = 0.0292 × 2 = 0.0584 M Cl¯.

Thus, the concentration of the chloride ion (Cl¯) in the solution is 0.0584 M

8 0
3 years ago
A more reactive metal displaces a less reactive metal from salt solution. Such reactions are called:
motikmotik

Answer:

Displacement Reaction.

6 0
3 years ago
Read 2 more answers
Separating mixtures: filtration​
Ymorist [56]

hi these are the answers :)

5 0
2 years ago
Arrange steps in order to describe what happens to a gas when it is cooled
AnnZ [28]

A) Particles of gas move slower.

B) Gas changes to liquid.

C) The gas loses thermal energy.

D) Gas particles decrease.

3 0
2 years ago
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