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3 years ago

How could you separate a mixture of rocks and sand?

Chemistry

1 answer:

ryzh [129]3 years ago

3 0

To separate a mixture of rocks and sand I think water will be the best option to break it down

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4. a type of civil engineering concerned with moving people and goods

makvit [3.9K]

Transportation seems like the right answer

6 0

1 year ago

Complete the sentences to explain what a similar treatment would predict for the effective nuclear charge on boron valence elect

dsp73

Answer:

ZcH's electrons = 5-2 = +3.

ZcH for inner electrons = -5 - 0 = +5.

Explanation:

Boron 1s² 2s² 2p

As, 2s ⇒ 2.58.

2p ⇒ 2.42.

Electrons = +3.

Greater than 2 cm = 0.35

Slightly greater than +3 .

8 0

3 years ago

The lock-and-key mechanism refers to

miskamm [114]

Answer:

A). The complementary shapes of an enzyme and a substrate.

Explanation:

The Lock-and-key mechanism was proposed by Emil Fischer for the first time and characterized as the metaphor which helps in elucidating the specificity of the enzymatic reactions. In this metaphor, the lock is described as the enzyme while 'key' is characterized as the substrate which the enzyme acts upon. If the key is not appropriately sized, it will not fit into the active site i.e. the keyhole of the lock or enzyme and reaction will not take place. Thus, option A is the correct answer.

5 0

3 years ago

Read 2 more answers

The zinc in a copper-plated penny will dissolve in hydrochloric acid if the copper coating is filed down in several spots (so th

LekaFEV [45]

Answer:

A penny dissolves in hydrochloric acid if the copper coating is filed down in several spot... ... When The Zinc In A Certain Penny Dissolves, The Total Volume Of Gas ... is filed down in several spots (so that the hydrochloric acid can reach the zinc). The reaction between the acid and the zinc 2H+(aq)+Zn(s)→H2(g)+Zn2+(aq) .

6 0

3 years ago

The depletion of ozone (O3) in the stratosphere has been a matter of great concern among scientists in recent years. It is belie

Deffense [45]

Answer: Nitric oxide is the limiting reagent. The number of moles of excess reagent left is 0.0039 moles. The amount of nitrogen dioxide produced will be 0.7912 g.

Explanation:

To calculate the number of moles, we use the equation

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ....(1)

For ozone:

Given mass of ozone = 0.827 g

Molar mass of ozone = 48 g/mol

Putting values in above equation, we get:

$\text{Moles of ozone}=\frac{0.827g}{48g/mol}=0.0172mol$

For nitric oxide:

Given mass of nitric oxide = 0.635 g

Molar mass of nitric oxide = 30.01 g/mol

Putting values in above equation, we get:

$\text{Moles of nitric oxide}=\frac{0.635g}{30.01g/mol}=0.0211mol$

For the given chemical equation:

$O_3+NO\rightarrow O_2+NO_2$

By Stoichiometry of the reaction:

1 mole of ozone reacts with 1 mole of nitric oxide.

So, 0.0172 moles of ozone will react with = $\frac{1}{1}\times 0.0172=0.0172moles$ of nitric oxide

As, given amount of nitric oxide is more than the required amount. So, it is considered as an excess reagent.

Thus, ozone is considered as a limiting reagent because it limits the formation of product.

Amount of excess reagent (nitric oxide) left = 0.0211 - 0.0172 = 0.0039 moles

By Stoichiometry of the reaction:

1 mole of ozone produces 1 mole of nitrogen dioxide.

So, 0.0172 moles of ozone will react with = $\frac{1}{1}\times 0.0172=0.0172moles$ of nitrogen dioxide

Now, calculating the mass of nitrogen dioxide from equation 1, we get:

Molar mass of nitrogen dioxide = 46 g/mol

Moles of nitrogen dioxide = 0.0172 moles

Putting values in equation 1, we get:

$0.0172mol=\frac{\text{Mass of nitrogen dioxide}}{46g/mol}\\\\\text{Mass of nitrogen dioxide}=0.7912g$

Hence, nitric oxide is the limiting reagent. The number of moles of excess reagent left is 0.0039 moles. The amount of nitrogen dioxide produced will be 0.7912 g.

8 0

3 years ago