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3 years ago

Describe each of the following as a physical or chemical property.

Chemistry

1 answer:

lidiya [134]3 years ago

7 0

Explanation:

Physical change -

It refers to any change during any process , where there is no new substance is formed , is referred to as a physical change.

Any change in the state of matter is characterised under physical change.

Chemical change -

It refers to any change in a chemical process , where there is formation of any new substance , is referred to as a chemical change .

From the options given in the question,

1. Apple turning brown , on air exposure , is an example of chemical change .

2. The physical state of mercury is liquid , is an example of physical change .

3. phosphorus burns on exposed to air , is an example of chemical change .

4. The gas Neon is colorless at the room temperature , is is an example of physical change .

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Neha and Reha are playing see-saw. Neha is sitting 60 cm away from the fulcrum and Reha is sitting 40 cm away from the fulcrum.

stich3 [128]

Answer:

Reha should apply 540 N to lift Neha.

Explanation:

L = 360 N

LD = 60 m

E =?

ED = 40m

NOW

L * LD = E * ED

360 *60 = E*40

21600/40 = E

540 N = E

4 0

3 years ago

Express this number in scientific notation 50000

Kazeer [188]

Answer:

We write 50,000 in scientific notation,

it is written as 5 x 10⁴.

Hope it helps.

6 0

3 years ago

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The system co2(g) + h2(g) ⇀↽ h2o(g) + co(g) is at equilibrium at some temperature. at equilibrium a 4.00 l vessel contains 1.00

Marina CMI [18]

<u>Answer:</u> The moles of $CO_2$ added to the system is 7.13 moles

<u>Explanation:</u>

We are given:

Moles of $CO_2$ at equilibrium = 1.00 moles

Moles of $H_2$ at equilibrium = 1.00 moles

Moles of $H_2O$ at equilibrium = 2.40 moles

Moles of $CO$ at equilibrium = 2.40 moles

Volume of the container = 4.00 L

Concentration is written as:

$\text{Molarity}=\frac{\text{Moles}}{\text{Volume (in L)}}$

The given chemical equation follows:

$CO_2(g)+H_2(g)\rightleftharpoons H_2O(g)+CO(g)$

The expression of $K_c$ for above equation follows:

$K_c=\frac{[CO][H_2O]}{[CO_2][H_2]}$

Putting values in above equation, we get:

$K_c=\frac{(\frac{2.40}{4.00})\times (\frac{2.40}{4.00})}{(\frac{1.00}{4.00})\times (\frac{1.00}{4.00})}\\\\K_c=5.76$

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Molarity of CO = 0.791 mol/L

Volume of solution = 4.00 L

Putting values in above equation, we get:

$0.791M=\frac{\text{Moles of CO}}{4.00L}\\\\\text{Moles of CO}=(0.791mol/\times 4.00L)=3.164mol$

Extra moles of CO = (3.164 - 2.40) = 0.764 moles

Let the moles of $CO_2$ needed be 'x' moles.

Now, equilibrium gets re-established:

$CO_2(g)+H_2(g)\rightleftharpoons H_2O(g)+CO(g)$

Initial: 1.00 1.00 2.40 2.40

At eqllm: (0.236+x) 0.236 3.164 3.164

Again, putting the values in the expression of $K_c$ , we get:

$5.76=\frac{(\frac{3.164}{4.00})\times (\frac{3.164}{4.00})}{(\frac{0.236+x}{4.00})\times (\frac{0.236}{4.00})}\\\\5.76=\frac{10.011}{0.056+0.236x}\\\\x=7.13$

Hence, the moles of $CO_2$ added to the system is 7.13 moles

4 0

3 years ago

Which phrase describes a typical feature of plains?

Airida [17]

Answer:

Usually have a low relief, can be interior, and can be coastal.- are phrases that describe typical features of plains.

5 0

3 years ago

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A sample of chemical X is found to contain 5.0 grams of oxygen, 10.0 grams of carbon, and 20.0 grams of nitrogen. The law of def

frozen [14]

Answer: 75 grams sample of chemical X should contain 21.43 grams of carbon

Explanation: The law of definite proportion states that a given chemical compound always contains its component elements in fixed ratio.

From the question, chemical X contains 5.0 grams of oxygen, 10.0 grams of carbon, and 20.0 grams of nitrogen.

Sum up the masses

5.0g + 10.0g + 20.0g = 35.0g

This means, 10.0 grams of carbon are present in 35.0 grams of chemical X.

Now, to the determine the mass of carbon that 75 gram sample of chemical X should contain,

According to the law of definite proportion, the component elements of a given chemical compound are in fixed ratio. Therefore,

If 35.0g of chemical X contains 10.0g of carbon

Then, 75 g of chemical X will contain

(75 × 10) / 35 g

= 21.43 grams

Hence, 75 grams sample of chemical X should contain 21.43 grams of carbon.

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3 years ago

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