Choose all the answers that apply.

What is the difference between the units rem and rad?

LenKa [72]

Answer:

Rem is used to measure biological risk, and rad is used to measure absorbed radiation.

Explanation:

6 0

3 years ago

7.The _____ theory of matter states that all particles of matter are in constant motion.

SashulF [63]

The kinetic energy theory of matter states that all particles of matter are in constant motion.
Kinetics has to do with some kind of movement, which is why this answer is the only plausible one.

6 0

3 years ago

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In Part III, the phenolphthalein indicator is used to monitor the equilibrium shifts of the ammonia/ammonium ion system. The phe

AnnZ [28]

The pink color in the solution fades. Some of the colored indicator ion converts to the colorless indicator molecule.

<h3>Explanation</h3>

What's the initial color of the solution?

$\text{NH}_4\text{Cl}$ is a salt soluble in water. $\text{NH}_4\text{Cl}$ dissociates into ions completely when dissolved.

$\text{NH}_4\text{Cl} \; (aq)\to {\text{NH}_4}^{+} \; (aq) +{\text{Cl}}^{-} \; (aq)$ .

The first test tube used to contain $\text{NH}_4\text{OH}$ . $\text{NH}_4\text{OH}$ is a weak base that dissociates partially in water.

$\text{NH}_4\text{OH} \; (aq) \rightleftharpoons {\text{NH}_4}^{+} \;(aq)+ {\text{OH}}^{-} \; (aq)$ .

There's also an equilibrium between $\text{OH}^{-}$ and ${\text{H}_3\text{O}}^{+}$ ions.

${\text{OH}}^{-}\;(aq) + {\text{H}_3\text{O}}^{+} \;(aq) \to 2\; \text{H}_2\text{O} \;(l)$ .

$\text{OH}^{-}$ ions from $\text{NH}_4\text{OH}$ will shift the equilibrium between $\text{OH}^{-}$ and ${\text{H}_3\text{O}}^{+}$ to the right and reduce the amount of ${\text{H}_3\text{O}}^{+}$ in the solution.

The indicator equilibrium will shift to the right to produce more ${\text{H}_3\text{O}}^{+}$ ions along with the colored indicator ions. The solution will show a pink color.

What's the color of the solution after adding NH₄Cl?

Adding $\text{NH}_4\text{Cl}$ will add to the concentration of ${\text{NH}_4}^{+}$ ions in the solution. Some of the ${\text{NH}_4}^{+}$ ions will combine with $\text{OH}^{-}$ ions to produce $\text{NH}_4\text{OH}$ .

The equilibrium between $\text{OH}^{-}$ and ${\text{H}_3\text{O}}^{+}$ ions will shift to the left to produce more of both ions.

${\text{OH}}^{-}\;(aq) + {\text{H}_3\text{O}}^{+} \;(aq) \to 2\; \text{H}_2\text{O} \;(l)$

The indicator equilibrium will shift to the left as the concentration of ${\text{H}_3\text{O}}^{+}$ increases. There will be less colored ions and more colorless molecules in the test tube. The pink color will fade.

7 0

3 years ago

The mass of water in a single popcorn kernel was found to be 0.905 grams after it popped at a temperature of 175 °C. Using the i

Rus_ich [418]

Answer:

0.583 kilojoules

Explanation:

The amount of heat required to pop a single kernel can be calculated using the formula as follows:

Q = m × c × ∆T

Where;

Q = amount of heat (J)

m = mass of water (g)

c = specific heat capacity of water (4.184 J/g°C)

∆T = change in temperature

From the given information, m = 0.905 g, initial temperature (room temperature) = 21°C , final temperature = 175°C, Q = ?

Q = m × c × ∆T

Q = 0.905 × 4.184 × (175°C - 21°C)

Q = 3.786 × 154

Q = 583.044 Joules

In kilojoules i.e. we divide by 1000, the amount of heat is:

= 583.04/1000

= 0.583 kilojoules

8 0

3 years ago

Which of the following measurements is used to measure the enthalpy of combustion? A. None of these B. Measuring the change in t

DaniilM [7]

Answer: Option (C) is the correct answer.

Explanation:

In a substance, the total energy of its molecular motion is known as heat. Whereas when we measure the average energy of molecular motion of a substance then it is known as temperature.

So, any increase or decrease in temperature will lead to change in heat of a substance.

When one mole of a substance is burned then the amount of energy released in the form of heat is known as heat of combustion.

Relation between heat and temperature is as follows.

q = $m \times C \times \Delta T$

Thus, we can conclude that to measure the enthalpy of combustion it cannot be measured, only calculated using the equation; q = $mc \Delta T$ .

4 0

3 years ago