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2 years ago

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Question 2 Which models of the atom from task 1 are not supported by Rutherfordâ€™s experimental evidence? For each of these mod

els, explain the experimental results that the model would predict.

1 answer:

kirill115 [55]2 years ago

8 0

Answer:

Sorry I don't know.

Explanation:

I'm only in middle school.

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What is the energy of a radio wave whose frequency is 6.2 x 106 Hz?

slava [35]

Answer:

657.2 Hz

Explanation:

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3 years ago

Using the periodic table, how would you find elements with chemical properties similar to helium?

rosijanka [135]

<span>The state of the helium in its natural form is gaseous and is a chemical element of colorless aspect and belongs to the group of noble gases. The atomic number of helium is 2. The chemical symbol of helium is He. For the following we focus on those elements and relate it with similar chemical properties. Then we find that; Neon, Hydrogen, Boron and Carbon are related to helium, either by proximity in their atomic number or period or by their group.</span>

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4 years ago

Compare and contrast the burning of wood and the metabolism of glucose in your cells. How are they similar, and how are they dif

Alisiya [41]

Burning of wood is a combustion reaction and the metabolism of glucose in your cells is cellular respiratory reaction.

Cellular respiration releases stored energy in glucose molecules and converts it into a form of energy that can be used by cells.

Cellular respiration is the process by which organisms combine oxygen with foodstuff molecules, diverting the chemical energy in these substances into life-sustaining activities and discarding, as waste products, carbon dioxide and water.

Wood as well as many common items that combust are organic (i.e., they are made up of carbon, hydrogen and oxygen). When organic molecules combust the reaction products are carbon dioxide and water (as well as heat)

Similarities:

1. Combustion reaction and metabolism of glucose both require oxygen.

2. Combustion and metabolism of glucose both product carbon dioxide and water

3. Both produces by-products: After cellular respiration and combustion have gotten what they needed from the wood, there will be byproducts from the conversion. In the case of combustion, they are noxious gases like carbon monoxide. In the case of respiration, the sugar molecule is broken into two molecules of pyruvic acid.

4. Catalyst: While breaking apart the bonds to release the stored energy either combustion or sugars for respiration the bonds will not broken by themselves. In each case, a catalyst is required to start the reaction that will break the bonds apart. In the case of combustion, the catalyst is a spark. Wood are flammable, so the spark will ignite the burning, breaking apart the bonds and releasing the energy. For respiration, enzymes are used to break the sugar molecule apart.

Differences

1. Glucose metabolism produces a chemical energy, while combustion produces light and heat energy.

2. Glucose metabolism is an endothermic reaction while combustion is an exothermic reaction (produces heat)

8 0

3 years ago

A scientist measures the standard enthalpy change for the following reaction to be -17.2 kJ : Ca(OH)2(aq) 2 HCl(aq)CaCl2(s)

elixir [45]

Answer: $\Delta H^{0}=-173.72$ kJ/mol

Explanation: <u>Enthalpy</u> <u>Change</u> is the amount of energy in a reaction - absorption or release - at a constant pressure. So, <u>Standard</u> <u>Enthalpy</u> <u>of</u> <u>Formation</u> is how much energy is necessary to form a substance.

The standard enthalpy of formation of HCl is calculated as:

$\Delta ^{0}=\Sigma H_{products}-\Sigma H_{reactants}$

$Ca(OH)_{2}_{(aq)}+2HCl_{(aq)}$ → $CaCl_{2}_{(s)}+2H_{2}O_{(l)}$

Standard Enthalpy of formation for the other compounds are:

Calcium Hydroxide: $\Delta H^{0}=$ -1002.82 kJ/mol

Calcium chloride: $\Delta H^{0}=$ -795.8 kJ/mol

Water: $\Delta H^{0}=$ -285.83 kJ/mol

Enthalpy is given per mol, which means we have to multiply by the mols in the balanced equation.

Calculating:

$-17.2=[-795.8+2(285.85)]-[-1002.82+2\Delta H]$

$-17.2=-1367.46+1002.82-2\Delta H$

$2\Delta H=17.2-364.64$

$\Delta H=-173.72$

So, the standard enthalpy of formation of HCl is -173.72 kJ/mol

8 0

3 years ago

What total volume of ozone measured at a pressure of 24.5 mmHg and a temperature of 232 K can be destroyed when all of the chlor

ddd [48]

Answer:

$1.75272\ \text{m}^3$

Explanation:

The breakdown reaction of ozone is as follows

$CF_3Cl + UV \rightarrow CF_3 + Cl$

$Cl + O_3 \rightarrow ClO + O_2$

$O_3 + UV \rightarrow O_2 + O$

$ClO + O \rightarrow Cl + O_2$

It can be seen that 2 moles of ozone is required in the complete cycle

So for 10 cycles, 20 moles of ozone is required

m = Mass of $CF_3Cl$ = 15.5 g

M = Molar mass of $CF_3Cl$ = 104.46 g/mol

P = Pressure = 24.5 mmHg

T = Temperature = 232 K

R = Gas constant = $62.363\ \text{L mmHg/K mol}$

Number of moles is given by

$n=\dfrac{m}{M}\\\Rightarrow n=\dfrac{15.5}{104.46}\\\Rightarrow n=0.1484\ \text{moles}$

$20\ \text{moles} = 20\times 0.1484 = 2.968\ \text{moles}$

From ideal gas law we have

$PV=nRT\\\Rightarrow V=\dfrac{nRT}{P}\\\Rightarrow V=\dfrac{2.968\times 62.363\times 232}{24.5}\\\Rightarrow V=1752.72\ \text{L}=1.75272\ \text{m}^3$

For 20 cycles of the reaction the volume of the ozone is $1.75272\ \text{m}^3$ .

7 0

3 years ago