A 90-m3 basement in a residence is found to be contaminated with radon coming from the ground through the floor drains. The concentration of radon in the room is 1.5 Bq · L−1 (becquerels per liter) under steadystate conditions. The room behaves as a CMFR, and the decay of radon is a first-order reaction with a decay rate constant of 2.09 × 10−6 s−1. If the source of radon is closed off and the room is vented with radon-free air at a rate of 0.14 m3 · s−1, how long will it take to lower the radon concentration to an acceptable level of 0.15 Bq · L−1?

Answer:

The mass of water is  14292.24 g

Explanation:

Given data:

Mass of cups and water = 142,99 g

Mass of cups = 6.76 g

Mass of water = ?

Solution:

Mass of cups + water = mass of cups + mass of water

Now we will rearrange the formula

mass of water = (Mass of cups + water) - mass of cups

Now we will put the values.

mass of water = 142,99 g + 6.76 g

mass of water = 14292.24 g

Thus mass of water is  14292.24 g.

Answer:

Explanation:

From the concept of equipartition energy, the energy for the respective degree of freedom is [tex]\dfrac{1}{2}K_BT[/tex]and for diatomic gas, the degree of freedom = 7

Thus, the heat capacity per molecule can be represented as:

[tex]C_v = \dfrac{7}{2} K_B[/tex]

For a heat capacity holding 5 moles of gas; we have:

= [tex]5\times \dfrac{7}{2}\times R[/tex]

Therefore;

C = [tex]5\times \dfrac{7}{2}\times 8.314[/tex]

C = 145.5

B.

The specific heat capacity = C/mass

where the mass of 5 moles of oxygen gas = 32 × 5 g

= 160 g

Thus; specific heat = 145.5/160

specific heat = 0.91 J/gK or 910 J/kg/K

C)

From the tables of specific heat at the given temperature of 300 K, we have:

0.918 J/gk and the estimated value is 0.92 J/gk

Therefore, the results are very near when compared to one another.

The branch of science in deals with chemicals and bonds is called chemistry. The reaction which requires heat to complete the reaction is called an endothermic reaction.

The correct answer to the question is option C has he empirically measured the specific heat of O2 gas at 300 K and compared it with your answer. Are we correct in assuming all the degrees of freedom are available?

The heat capacity is as follows:-

[tex]C_v =\frac{7}{2}Kb \\\\=5*\frac{7}{2} *R\\\\=5*\frac{7}{2}*8.314\\\\C= 145.5[/tex]

The specific heat capacity = C/mass, where the mass of 5 moles of oxygen gas = 32 × 5 g

= 160 g

Thus; specific heat = 145.5/160

specific heat = 0.91 J/gK or 910 J/kg/K.

Hence, the correct answer to the question is option C.

For more information about the question, refer to the link:-

https://brainly.com/question/1453843

Explanation:

Hey there!

The differences between physical chamge and chemical change are;

Hope it helps...

Answer: 3.0 g/cm3

Problem 1: You have a rock with a volume of 15cm3 and a mass of 45 g. What is its density? Density is mass divided by volume, so that the density is 45 g divided by 15cm3, which is 3.0 g/cm3

Explanation: The top question answer is 3.00 g/cm3 .... I hope this helps!!! (PLEASE RATE ME AS BRAINLY)

Answer: 15 METERS IN A SECOND

Explanation: 54km = 54000m    54000m / 60 = 900    900/60 = 15

Answer:

Explanation:

For the Magnesium Ion, ([tex]Mg^{+2}[/tex])

Electrons:  10

Protons: 12

Neutrons: 12

Answer:

a rock can be composed by many minerals

Explanation:

these are some tipes of rocks

igenious

metamorphic

sedimentary

(if this is not wat u want then tell me pls so i can help :)

Answer:

Conclusion

Explanation:

Answer:

Explanation:

This question is both theoretical and practical. While the theoretical aspect will be detailed fully here, the practical aspect will be provided as a form of guidance.

Water generally boils at 100°C when altitude (in feet) is 0. One of the colligative properties that occurs when salt is added to water is that there is a boiling point elevation(meaning an increase in boiling point). For instance, if 20g of salt is added to about 5.3 quarts of water, the boiling point of water will increase from 100°C to 100.04°C.

However, when the altitude/elevation of a place is about 7000 ft (like in Flagstaff, Arizona), water will boil at 95.3°C. In order to get 2 quarts of water to boil at 100°C in Flagstaff;

20g causes an increase in boiling point by 0.04°C (100°C to 100.04°C) in 5.3 quarts of water

What gram will increase the boiling point by same 0.04°C in 2 quarts

20g ⇒ 5.3

X ⇒ 2

5.3 X ⇒ 40g

X = 40 ÷ 5.3

X = 7.55g

Hence, 7.55g will cause an increase in boiling point by 0.04°C (from 100°C to 100.04°C) in 2 quarts of water

What mass of salt will increase the boiling point by 4.7°C (95.3°C to 100°C)

7.55g ⇒ 0.04

X ⇒ 4.7

X × 0.04 ⇒ 7.55 × 4.7

0.04X ⇒ 35.5

X = 887.5g

Hence, in order for the spaghetti water to boil at 100°C, 887.5g of salt needs to be added.

For the practical part of the question, some Kitchen scales have an accuracy of .25kg (250g) and some have an accuracy of .2 kg (200g) and some have an accuracy of .5kg (500g). The one your kitchen has will determine the amount of salt that you can measure. For example, if your kitchen scale/balance has an accuracy of 250g/0.25kg, then you can only measure 750g of the 887.5g (as the rest is 137.5g, which is not up to 250g of the scale's accuracy) of the required salt measurement. However, if you have a digital balance that can measure up to 2kg/2000g in one decimal place, that's the perfect balance to measure this salt.

Answer:

[tex]Molec_{\ H_{tot}}=1.206x10^{25}molec[/tex]

Explanation:

Hello.

In this case, taking into account that HCl has one molecule of hydrogen per mole of compound which weights 36.45 g/mol, we compute the number of molecules of hydrogen in hydrochloric acid by considering the given mass and the Avogadro's number:

[tex]molec_{\ H}=3.65gHCl*\frac{1molHCl}{36.45gHCl} *\frac{1molH}{1molHCl}*\frac{6.022x10^{23}molec_\ H}{1molH} =6.03x10^{22}molec[/tex]

Now, from the 180 g of water, we see two hydrogen molecules per molecule of water, thus, by also using the Avogadro's number we compute the molecules of hydrogen in water:

[tex]molec_{\ H}=180gH_2O*\frac{1molH_2O}{18gH_2O} *\frac{2molH}{1molH_2O}*\frac{6.022x10^{23}molec_\ H}{1molH} =1.20x10^{25}molec[/tex]

Thus, the total number of molecules turns out:

[tex]Molec_{\ H_{tot}}=6.03x10^{22}+1.20x10^{25}\\\\Molec_{\ H_{tot}}=1.206x10^{25}molec[/tex]

Regards.

We know, change in temperature is given by :

[tex]T_2-T_1=\dfrac{q}{mC_p(Gold)}[/tex]

Putting all given values, we get :

[tex]T_2-T_1=\dfrac{70\ cal}{20\ g\times 0.0310\ cal/g^o\ C}\\\\T_2-T_1=112.90^oC\\\\T_2-35^oC=112.90^oC\\\\T_2=(112.90+35)^oC\\\\T_2=147.9^oC[/tex]

Hence, this is the required solution.

Answer:

ion now i jus want points sorry

Explanation:

evaporation because the water is coming out of the water into the air

Answer:

A= 2, B= 1

Explanation:

In the given electronic configuration of Lithium, the values of A and B are 2 and 1, respectively.

The electronic configuration of an atom describes how its electrons are distributed among the various energy levels and orbitals. It is typically represented using a series of numbers and symbols that indicate the number of electrons in each orbital.

To complete the electron configuration for lithium (Li), we'll refer to the periodic table:

The atomic number of lithium is 3, which means it has 3 electrons. The electron configuration for lithium can be determined as follows:

[tex]1s^2 2s^1.[/tex]

In this case,

So, for lithium (Li), the completed electron configuration is:

[tex]1s^2 2s^1.[/tex]

Therefore, the values of A and B in the given electronic configuration of Lithium are A = 2, B = 1, respectively.

Learn more electronic configuration about here:

https://brainly.com/question/29157546

#SPJ2

Answer:

D

Explanation:

Have a nice day

Among the following observations which is usually not evidence of a chemical change is change of a shape.

Chemical changes will occur when the composition of the substance is changes internally or converted into any new product.

So, change of shape is not a chemical change.

To know more about chemical change, visit the below link:

https://brainly.com/question/26018275

Explanation:

The gravitational force between two objects is given by :

[tex]F=G\dfrac{m_1m_2}{d^2}[/tex]

Where

G is universal gravitational constant

d is the distance between two masses

The gravitational force is inversely proportional to the distance between objects. It means when the distance between objects increases, gravitational force decreases and vice versa. To decrease the gravitational force between two objects, distance must increase.

Answer:

You have to increase the distance between two objects.

Explanation:

I took the K12 quiz and this was the correct option.

Hope I helped

Answer:

silicon and oxygen

Explanation:

silicon dioxide means silicon+ 2 oxygen

Answer:

Half

Non-covalently bonded

Elastic collisions

Explanation:

When two atoms are close to each other and are not bonded to each other, the distance between them is the Van Der Waals radius of the compound.

When atoms of gases are not bonded together, they collide with each other in an elastic manner. Kinetic energy and linear momentum are conserved.

Answer:

A water molecule

Explanation:

The removal of a phosphate molecule from ATP to form ADP is a hydrolysis reaction. Hydrolysis reactions require water and release energy.

The converse reaction - when a phosphate is added to a molecule of ADP to form ATP - releases water and requires energy.

Answer:

Part A. p, n = 31, 38.

Part B. p, n = 31, 40.

Part C. [tex]^{69}_{31}Ga,\ ^{71}_{31}Ga[/tex]

Explanation:

Hello,

Part A.

In this case, since the atomic number for gallium is 31, we can say that the first isotope has also 31 protons and the neutrons are computed by using its molar mass as a whole number (69):

[tex]neutrons=mass-protons=69-31=38[/tex]

Thus, result is p, n = 31, 38.

Part B.

In this case, since the atomic number for gallium is 31, we can say that the second isotopes has also 31 protons and the neutrons are computed by using its molar mass as a whole number (71):

[tex]neutrons=mass-protons=71-31=40[/tex]

Thus, result is p, n = 31, 40.

Part C.

Finally, the isotopes as shown as:

[tex]^{69}_{31}Ga,\ ^{71}_{31}Ga[/tex]

Best regards.

Explanation:

Iron, like other metals, conducts heat and electricity, has a luster, and forms positive ions in its chemical reactions. Pure iron is fairly soft and can easily be shaped and formed when hot. Its color is silvery white. Iron is easily magnetized.

Answer:

physical properties:

1. Pure iron greyish white in colour  

2. Iron is a heavy metal. Its density is 7.86 g cm-3.

3. Its melting point is 1539`C.

4. It is highly malleable and ductile.

5. It is ferromagnetic, that is, it becomes strongly magnetised when placed in a magnetic field.

6. It has high tensile strength.

chemical properties:

1. Iron is the 4th most abundant element in the Earth’s crust, and it is an integral chemical element found in the human body.

2. It is placed in the first transition series of the periodic table, and is known to be an important transition metal.

3. It mainly exists in the +2 and +3 oxidation states.

4. Iron (II) compounds are known as ferrous, while iron (III) compounds are known as ferric.

5. Iron (II) compounds are light green in color, while iron (III) compounds are orange/brown in color.

6. Iron is the only naturally occurring substance that has magnetic properties. Magnetism is, in fact, one of its most remarkable properties.

hope it helps :)))

Answer:

The nucleus represents a major evolutionary transition. As a consequence of separating translation from transcription many new functions arose, which likely contributed to the remarkable success of eukaryotic cells. Here we will consider what has recently emerged on the evolutionary histories of several key aspects of nuclear biology; the nuclear pore complex, the lamina, centrosomes and evidence for prokaryotic origins of relevant players.

Answer:

nickel (Ni)

Explanation:

Answer: [tex]5.35* 10^-^5[/tex]

Explanation:

You gotta move the decimal place over 5 places. That means the power will be -5

Answer:

5.35 × 10⁻⁵

This is the representation for 0.0000535 in scientific notation, because you must move it 5 spaces. Hope this helps!

Answer:

peroid num= 3

group num=13  (boron Group)

Explanation:

Answer:

period

3

group

13

Answer:

The Avogadro's Number will reduce in value

Explanation:

From the question we are told that

The current pass through the short circuit is [tex]0.1 *I[/tex]

Here I is the total current

Generally Avogadro's Number is mathematically represented as

[tex]N_A = \frac{Q}{ 2 * n * e}[/tex]

Here Q is the charge which is mathematically represented as

[tex]Q = It[/tex]

        n  is number of moles

        e is the charge on an electron

 So

       [tex]N_A =  \frac{I * t }{ 2 *  n * e}[/tex]

Now when the current decreases from 100% to  90% due to the short circuit . this will also reduce  the no of moles of metal  dissolved hence from the equation we see that the Avogadro's Number will reduce