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anyanavicka [17]

3 years ago

11

A radioisotope is placed near a radiation detector, which registers 80 counts per second. Eight hours later, the detector regist

ers 5 counts per second. What is the half- life of the radioactive isotope

1 answer:

sukhopar [10]3 years ago

8 0

The half life is that the material loses 1/2 of its mass every two hours

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Please help is for today

love history [14]

Answer:

Our bodies are designed to regulate our temperature. When it's cold outside, your body makes sure to keep the blood flowing to your core and vital organs to keep them warm. This can change the amount of blood flow to your hands and feet, making them feel cold

5 0

3 years ago

A mass of 34.05 g of H2O(s) at 273 K is dropped into 185 g of H2O(l) at 310. K in an insulated container at 1 bar of pressure. C

kykrilka [37]

Answer:

The temperature of the system once equilibrium is reached, is 292 Kelvin

Explanation:

Step 1: Data given

Mass of H2O = 34.05 grams

⇒ temperature = 273 K

Mass of H2O at 310 K = 185 grams

Pressure = 1 bar = 0.9869 atm

Step 2: Calculate the final temperature

n(ice)*ΔH(ice fusion) + n(ice)*CP(H2O)(Tfinal- Ti,ice) + n(H20)*CP(H2O)*(Tfinal-Ti,H2O) = 0

Tfinal = [n(ice)*CP(ice)*Ti(ice) + n(H2O)*CP(H2O)*Ti(H20) - n(ice)*ΔH(ice fusion)] / [n(ice)*CP(ice) +n(H2O)*CP(H2O)]

⇒ with n(ice) = moles of ice = 34.05 grams / 18.02 g/mol = 1.890 moles

⇒ with CP(ice) = 75.3 J/K*mol

⇒ with Ti(ice) = the initial temperature of ice = 273 K

⇒ with n(H2O) = the moles of water = 185.0 grams / 18.02 g/mol = 10.27 moles

⇒ with CP(H2O) = CP(ice) = 75.3 J/K*mol

⇒ with Ti(H2O) = the initial temperature of the water = 310 K

⇒ with ΔH(ice, fusion) = 6010 J/mol

Tfinal = [1.890 moles * 75.3 J/K*mol * 273 + 10.27 mol * 75.3 J/K*mol * 310 K - 1.890 moles * 6010 J/mol] / [1.890 moles *75.3J/k*mol + 10.27 mol * 75.3 J/K*mol]

38852.541 + 239732.61 - 11358.9 = 267226.251

Tfinal= 291.8 ≈ 292 Kelvin

The temperature of the system once equilibrium is reached, is 292 Kelvin

8 0

4 years ago

The electron configuration that belongs to the atom with the lowest first ionization energy is?

sasho [114]

The electron configuration that belongs to the atom with the lowest first ionization energy is francium.

<h3>What is ionization energy? </h3>

Ionization energy is defined as the minimum amount of energy required to remove the most loosely electron present in outermost shell.

<h3>Ionization energy across period</h3>

Ionization energy increase as we move from left to right in the period. This can be explained as when we move from left to right along period new electron is added to the same shell which increase the nuclear charge. Hence results int he decrease in size. Due to this decrease in size more energy is required to remove electron from outermost shell.

<h3>Ionization energy along group</h3>

Ionization energy decrease as we move from top to bottom along group. This can be explained as we move from top to bottom new electron is added to new shell. Due to addition of new shell the size of atom increases which results in the decrease in the nuclear charge. Due to this less amount of energy is needed to remove an electron.

Thus, we concluded that the electron configuration that belongs to the atom with the lowest first ionization energy is francium.

learn more about ionization energy:

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4 0

2 years ago

If your sample contained a volatile impurity, what value would be in error

weeeeeb [17]

A volatile impurity, is an impurity that evaporates quickly, so, if you were to conduct an experiment on a substance with this type of impurity, the evaporation point, and the mass of the substance at high temperatures would be in error.

6 0

3 years ago

Kamila [148]

2. High tempertaure and low pressure

3. HCL,NH3,H20

4. higher collisions ieThe greater the number of gas molecules, higher will be the collision rate and hence the greater the pressure.

Explanation:

Expansion:

1. Suppose gas particles are moving in a linear fashion but if they collide with some thing they will fil that. This explains expansion theory of gases.

Fluidity: The gas molecules are in dependent of each other and have low density, they are in constant motion hence have fluidity.

low density: The gas molecules are far apart as compared to solid and liquid hence have low density.

compressibility: Due to the large distance between the gas molecules they collide with each other and vessel wall and when the space is constricted they start moving faster. They are elastic in nature.

Diffusion: Yes, because when gas is mixed it starts moving in the mixture randomly.

2. The molecules in real gas are at large distance. The high temperature and low pressure real gas would behave ideally. Because increase temperature would cause higher movement of gas particles.

3. HCL, NH3 and H2O are polar gases they will have relatively different attractive forces between them.

4. The greater the number of gas molecules, higher will be the collision rate and hence the greater the pressure.

5. The gas particles get closer, enough pressure not provided. It increases the kinetic energy as heat is produced due to compaction of molecules. The particles would not move and will become liquid causing volume to increase.

6. The gas molecules start moving rapidly, move farther apart .Volume and pressure also increases.

8 0

4 years ago