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3 years ago

Q2 Different metals were discovered at different times throughout history. In general,

Chemistry

1 answer:

castortr0y [4]3 years ago

4 0

Answer:

The first metal known to be prepared from its ore was copper, perhaps as early as 6000BC6000BC in the Middle East. The ore, which contained copper(II) oxide, was heated with charcoal, which was prepared by the incomplete burning of wood, and is mainly elemental carbon. Later, iron and tin were prepared in the same way. Bronze, an alloy of copper and tin, was made by mixing copper-containing ore with tin ore and heating the mixture in the presence of charcoal.

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The freezing point of water H2O is 0.00°C at 1 atmosphere. A nonvolatile, nonelectrolyte that dissolves in water is urea. If 13.

Trava [24]

Answer:

Molality = 1.46 molal

The freezing point of the solution = -2.72 °C

Explanation:

Step 1: Data given

The freezing point of water H2O is 0.00°C at 1 atmosphere

urea = nonelectrolyte = van't Hoff factor = 1

Mass urea = 13.40 grams

Molar mass urea = 60.1 g/mol

Mass of water = 153.2 grams

Molar mass H2O = 18.02 g/mol

Kf = 1.86 °C/m

Step 2: Calculate moles urea

Moles urea = mass urea /molar mass urea

Moles urea = 13.40 grams / 60.1 g/mol

Moles urea = 0.223 moles

Step 3: Calculate the molality

Molality = moles urea / mass water

Molality = 0.223 moles / 0.1532 kg

Molality = 1.46 molal

Step 4: Calculate the freezing point of the solution

ΔT = i * Kf * m

ΔT = 1* 1.86 °C/m * 1.46 m

ΔT = 2.72 °C

The freezing point = -2.72 °C

3 0

3 years ago

What material is least likely to be recognized as a mixture by looking under a microscope

I am Lyosha [343]

A homogenous mixture is uniform and thus hard to recognize as a mixture. An example is water.

6 0

4 years ago

3. What is the greatest amount of H2O that can be made with 3.8 moles of H and 5 moles of

Pachacha [2.7K]

Answer: Hello!

first i believe we need a balanced equation to start...

i got 2H2 + 1O2 = 2H2O

This tells us that we need 2 moles of H2 for every 1 mole of O2 Since we only have 1 mole of H2 compared to the 5 moles of O2 hydrogen is the limiting reagent. For illustration, divide the balanced equation by 2 in order to get 1 mole of H2 If we start with 1.0 moles of H2 we'll produce 1.0 mole of H2O

Your welcome <3

Explanation:

3 0

2 years ago

What type of bond results from the electrostatic attraction between positive and negative atoms?

Juliette [100K]

It is called a ionic bond

4 0

3 years ago

You observe an exothermic gaseous reaction that is not spontaneous in forward direction at 1 atm and 298K. Which of the followin

m_a_m_a [10]

Answer: option (a) is the correct answer

Explanation:

The complete questions says;

You observe an exothermic gaseous reaction that is not spontaneous in forward direction at 1 atm and 298K. Which of the following statements about this reaction is true? a. This reaction will become spontaneous in forward direction at some temperature below 298K. b. This reaction will be spontaneous in forward direction at a higher pressure at 298K. c. This reaction will become spontaneous in forward direction at some temperature above 298K. d. This reaction is never spontaneous. e. The reverse reaction is always spontaneous.

The Answer:

(a). This reaction will become spontaneous in forward direction at some temperature below 298K

Explanation: First of all, we can acknowledge that the reaction seen here is an exothermic one, i.e energy is released in the process outwardly and as a result temperature is reduced during this process of energy loss.

Having understood that scenario, say we reduce it's temperature by ourself than forward reaction favors and after reaching at particular temperature, therefore we can confirm this to be a spontaneous reaction.

Let us use this to confirm what we have been saying.

Given;

ΔG = ΔH - TΔS

here ΔH is negative

it is non spontaneous, which means ΔG is positive so we continuously decraeses it's temperature than at a particular temperature.

The Entropy change becomes positive and reaction becomes spontaneous and ΔG become negative.

cheers i hope this helped !!

8 0

3 years ago