All categories

4 years ago

If most objects are made up of free space then why can we put our hands through a book or wall?

1 answer:

4 0

I suppose you mean to ask why we can't go through obstacles.

Any atom is surrounded by an electronic cloud. When two atoms get close to each other, the electronic clouds repel each other, preventing them from interpenetrating each other. That same phenomenon, on a larger scale, prevents us from going through matter.

You might be interested in

In a laboratory investigation, an HCl(aq) solution with a pH value of 2 is used to determine the molarity of a KOH(aq) solution.

guapka [62]

Answer:

blue

Explanation:

KOH is a base therefore it's pH will be above seven. According to table M when tested with the indicator bromcreeol green The solution will turn blue

5 0

3 years ago

Please helppp I need 1 paragraph I’m about to go to school

kifflom [539]

The data on Climate change is as explained below-

Explanation:

Climate change is the ominous “hard truth” concurrently. However, it is not the first time that climate change is happening. In geological history, we find plenty of evidence of climate change.

The most important and famous of all such changes is the climate change that occurred during the Mesozoic era leading to the extinction of Dinosaurus. The reason behind these all climate changes was different. However, the climate change we are witnessing at present has something extra to all this natural stuff.

The present climate change is fuelled by anthropogenic activities at large. Large scale emission of greenhouse gases possibly from burning of fossil fuels ever since the Industrial revolutions in the late 18th century has altered the chemical composition of atmospheric gases. In addition to the use of fossil fuels other activities such as agriculture, coal-based power plants, deforestation and other such activities have been instrumental in degrading the serene balance between different atmospheric gases.

The evidence of the present climate change can be gauged in-

The rise in global average temperature-Earth’s mean temperature has risen by around 1° C ever since the 19th century. 2017 proved to be the warmest year in the record.
Oceans have been net absorber of the heat. This has led to the warming up of oceans. This severely hampers and impact marine flora and fauna
Deglaciation- the increasing temperature has manifested in the form of shrinking ice-sheets. Large icebergs are calving and thus has some serious long-term impact for the sustenance of mankind.
Rise in the mean sea level- The sea level has risen by almost 10 inches since last century. This increase is all set to increase in future thus endangering the lives and livelihood of the coastal communities.

All the leading personalities of the time including the ex-president of the US Mr Barak Obama emphasised the importance of climate change and urged the global community to tackle it at earliest. In his words, he mentioned, “No other challenge poses as great a threat to the future generation as the climate change”. In addition to Mr Obama, noted climate activist Greta Thunberg described the climate change to be the greatest crisis to the humanity that it has ever faced.

Therefore, it can be safely argued that it’s urgent to talk and act tough on climate change. Climate change has transitioned into a multi-headed monster capable enough to devastate the entire mankind. It has done this earlier and sure to carry it further on.

3 0

3 years ago

(I)how many atoms are present in 7g of lithium?

ICE Princess25 [194]

Answer :

(i) The number of atoms present in 7 g of lithium are, $6.07\times 10^{23}$

(ii) The number of atoms present in 7 g of lithium are, $1.204\times 10^{24}$

(iii) The number of moles of $F_2$ is, 1 mole

The number of moles of $CO_2$ is, 0.5 mole

The number of moles of $OH^-$ is, 1 mole

Explanation :

Part (i) :

First we have to calculate the moles of lithium.

$\text{Moles of }Li=\frac{\text{Mass of }Li}{\text{Molar mass of }Li}$

Molar mass of Li = 6.94 g/mole

$\text{Moles of }Li=\frac{7g}{6.94g/mol}=1.008mole$

Now we have to calculate the number of atoms present.

As, 1 mole of lithium contains $6.022\times 10^{23}$ number of atoms

So, 1.008 mole of lithium contains $1.008\times 6.022\times 10^{23}=6.07\times 10^{23}$ number of atoms

Thus, the number of atoms present in 7 g of lithium are, $6.07\times 10^{23}$

Part (ii) :

First we have to calculate the moles of carbon.

$\text{Moles of }C=\frac{\text{Mass of }C}{\text{Molar mass of }C}$

Molar mass of C = 12 g/mole

$\text{Moles of }C=\frac{24g}{12g/mol}=2mole$

Now we have to calculate the number of atoms present.

As, 1 mole of carbon contains $6.022\times 10^{23}$ number of atoms

So, 2 mole of carbon contains $2\times 6.022\times 10^{23}=1.204\times 10^{24}$ number of atoms

Thus, the number of atoms present in 7 g of lithium are, $1.204\times 10^{24}$

Part (iii) :

To calculate the moles of $F_2$ :

$\text{Moles of }F_2=\frac{\text{Mass of }F_2}{\text{Molar mass of }F_2}$

Molar mass of $F_2$ = 38 g/mole

$\text{Moles of }F_2=\frac{19g}{19g/mol}=1mole$

Thus, the number of moles of $F_2$ is, 1 mole

To calculate the moles of $CO_2$ :

$\text{Moles of }CO_2=\frac{\text{Mass of }CO_2}{\text{Molar mass of }CO_2}$

Molar mass of $CO_2$ = 44 g/mole

$\text{Moles of }CO_2=\frac{22g}{44g/mol}=0.5mole$

Thus, the number of moles of $CO_2$ is, 0.5 mole

To calculate the moles of $OH^-$ ions :

$\text{Moles of }OH^-=\frac{\text{Mass of }OH^-}{\text{Molar mass of }OH^-}$

Molar mass of $OH^-$ = 17 g/mole

$\text{Moles of }OH^-=\frac{17g}{17g/mol}=1mole$

Thus, the number of moles of $OH^-$ is, 1 mole

4 0

3 years ago

What volume of propane (C3H8) is required to produce 165 liters of water according to the following reaction? (All gases are at

inna [77]

Answer:

We need 41.2 L of propane

Explanation:

Step 1: Data given

volume of H2O = 165 L

Step 2: The balanced equation

C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(g)

Step 3: Calculate moles of H2O

1 mol = 22.4 L

165 L = 7.37 moles

Step 4: Calculate moles of propane

For 1 mol C3H8 we need 5 moles O2 to produce 3 moles CO2 and 4 moles H2O

For 7.37 moles H2O we need 7.37/4 = 1.84 moles propane

Step 5: Calculate volume of propane

1 mol = 22.4 L

1.84 moles = 41.2 L

We need 41.2 L of propane

6 0

4 years ago

John measures the mass of a cup of chocolate milk and a glass of orange Juice. He places both containers on a balance scale. He

mylen [45]

Answer:

b. John has to pour each liquid into a container with the same mass and then compare them

would be the correct answer. Hope this helps!

Explanation:

5 0

3 years ago