All categories

3 years ago

Is erasing a pencil mark a chemical or physical change?

Chemistry

1 answer:

yKpoI14uk [10]3 years ago

6 0

Physical change because the eraser doesn’t have an chemical reaction to it.

You might be interested in

How many significant digits in 0.23100

Reil [10]

Answer:

There are 5 significant digits in 0.23100.

Explanation:

This is because all non-zero digits are considered significant and zeros after decimal points are considered significant.

4 0

4 years ago

Which of the following bodily organs or systems can be affected by ionizing radiation?

GrogVix [38]

The correct answer is the fourth option. The nervous system is the system in the body which can be affected by ionizing radiation. Exposure to this kind of radiation may lead to changes in motor function or neurological disorders.

5 0

3 years ago

Calculate the solubility of hydrogen in water at an atmospheric pressure of 0.380 atm (a typical value at high altitude).

Pani-rosa [81]

The question is incomplete, here is the complete question:

Calculate the solubility of hydrogen in water at an atmospheric pressure of 0.380 atm (a typical value at high altitude).

Atmospheric Gas Mole Fraction kH mol/(L*atm)

$N_2$ $7.81\times 10^{-1}$ $6.70\times 10^{-4}$

$O_2$ $2.10\times 10^{-1}$ $1.30\times 10^{-3}$

Ar $9.34\times 10^{-3}$ $1.40\times 10^{-3}$

$CO_2$ $3.33\times 10^{-4}$ $3.50\times 10^{-2}$

$CH_4$ $2.00\times 10^{-6}$ $1.40\times 10^{-3}$

$H_2$ $5.00\times 10^{-7}$ $7.80\times 10^{-4}$

<u>Answer:</u> The solubility of hydrogen gas in water at given atmospheric pressure is $1.48\times 10^{-10}M$

<u>Explanation:</u>

To calculate the partial pressure of hydrogen gas, we use the equation given by Raoult's law, which is:

$p_{\text{hydrogen gas}}=p_T\times \chi_{\text{hydrogen gas}}$

where,

$p_A$ = partial pressure of hydrogen gas = ?

$p_T$ = total pressure = 0.380 atm

$\chi_A$ = mole fraction of hydrogen gas = $5.00\times 10^{-7}$

Putting values in above equation, we get:

$p_{\text{hydrogen gas}}=0.380\times 5.00\times 10^{-7}\\\\p_{\text{hydrogen gas}}=1.9\times 10^{-7}atm$

To calculate the molar solubility, we use the equation given by Henry's law, which is:

$C_{H_2}=K_H\times p_{H_2}$

where,

$K_H$ = Henry's constant = $7.80\times 10^{-4}mol/L.atm$

$p_{H_2}$ = partial pressure of hydrogen gas = $1.9\times 10^{-7}atm$

Putting values in above equation, we get:

$C_{H_2}=7.80\times 10^{-4}mol/L.atm\times 1.9\times 10^{-7}atm\\\\C_{CO_2}=1.48\times 10^{-10}M$

Hence, the solubility of hydrogen gas in water at given atmospheric pressure is $1.48\times 10^{-10}M$

4 0

3 years ago

Most metals allow electricity to flow freely through them. So, most metals are.....

algol [13]

Answer:

Conductors

Explanation:

Metals that are conductors let electric currents flow freely. Insulators have a resistance of a charge to flow through them.

5 0

3 years ago

Read 2 more answers

The scientific method is sometimes seen as more of a cycle than a linear process. Which statement gives a major

irakobra [83]

Answer:

Explanation:

When a conclusions is shared it gives room for other scientist with other ideas or different perspective to raise up new questions

4 0

3 years ago