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3 years ago

Explain properties of waves and how these properties apply to the quantum model

1 answer:

6 0

The existence of atoms began to be accepted around 1910 when many theories called upon the fact that atoms most exist (for example the work of Boltzmann trying to explain entropy, died 1906). At that time atoms were seen as tiny small ball like objects, all matter was composed of. the models have been advanced ever since. Key names that are worth looking up are J. J. Thomson, Rutherford, Bohr and de Broglie. Explain how different observations and experiments led to changes in the atomic model. Many of the models that the men above proposed were created upon what they saw from their experiments. An example is that Niels Bohr wanted to explain the spectral lines in hydrogen, introducing the energy shells are quantized.

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Match the element with its description. Match Term Definition Potassium A) Great conductor of heat and electricity Barium B) Mal

mezya [45]

<span>Barium - A) Great conductor of heat and electricity Potassium - B) Malleable and highly reactive Boron - C) Has properties of both metals and nonmetals Neon - D) Nonreactive gas Let's look at each element and it's place on the periodic chart to see what matches. Potassium - This is on the far left column for alkali metals. This means it's highly reactive and since it's a metal, it's both malleable and conductive. Looking at the available options, "B) Malleable and highly reactive" is the best choice. Barium - This element is in the second column from the left, so it's a fairly reactive metal, but not nearly as reactive as Potassium above. So "A) Great conductor of heat and electricity" is the best choice here, although I wouldn't call it "great". The resistivity of barium is about 20 times larger than copper. Boron - This element is about in the middle of the periodic chart, so it does have the properties of both metals and nonmetals. So "C) Has properties of both metals and nonmetals" is the best choice. Neon - This is in the far right column for noble gasses. Very non-reactive. So "D) Nonreactive gas" is the best choice.</span>

5 0

4 years ago

A BaSO4 slurry is ingested before the gastrointestinal tract is x-rayed because it is opaque to x-rays and defines the contours

NNADVOKAT [17]

Explanation:

The given reaction equation is as follows.

$BaSO_{4}(s) \rightleftharpoons Ba^{2+}(aq) + SO_{4}^{2-}(aq)$

The value of $\Delta G^{o}$ = 59.1 kJ/mol

We know that ,

$\Delta G^{o} = -RT ln K_{sp}$

or, $ln K_{sp} = -(\frac{\Delta G^{o}}{RT})
$

= -(\frac{59.1 kJ/mol}{(8.314 \times 10^{-3} kJ/mol.K \times 310 K))}[/tex]

= -22.93

or, $K_{sp} = e^{-22.93}$

= $1.1 \times 10^{-10}$

$K_{sp} = [Ba^{2+}][ SO_{4}^{2-}]$

Therefore, $[Ba^{2+}] =\sqrt{K_{sp}}$

= $\sqrt{ 1.1 \times 10^{-10}}$

= $1.05 \times 10^{-5} M$

Therefore, we can conclude that the value of $[Ba^{2+}]$ in the intestinal tract is $1.05 \times 10^{-5} M$ .

7 0

3 years ago

The heat capacity of air is much smaller than that of water, and relatively modest amounts of heat are needed to change its temp

LekaFEV [45]

Answer:

$Q=9.2x10^5J$

$t=614s=10.2min$

Explanation:

Hello,

In this case, we can compute the energy by using the following formula for air:

$Q=nCp\Delta T$

Whereas the moles of air are computed via the ideal gas equation at room temperature inside the 5.5m x 6.5m x 3.0m-room:

$n=\frac{PV}{RT}\\\\V=5.5m*6.5m*3.0m=107.25m^3*\frac{1000L}{1m^3}=107250L\\ \\n=\frac{1atm*107250L}{0.082\frac{atm*L}{mol*K}*298.15K}\\ \\n=4386.8mol$

Now, we are able to compute heat, by considering that the temperature raise is given in degree Celsius or Kelvins as well:

$Q=4386.8mol*21\frac{K}{mol*K}*10K \\\\Q=9.2x10^5J$

Finally, we compute the time required for the heating by considering the heating rate and the required heat, shown below:

$t=\frac{9.2x10^5J}{1.5\frac{kJ}{s}*\frac{1000J}{1kJ} } \\\\t=614s=10.2min$

Regards.

8 0

3 years ago

A 1.775g sample mixture of potassium hydrogen carbonate is decomposed by heating. if the mass loss is 0.275g what is the percent

Marina86 [1]

A 1.775g sample mixture of KHCO₃ is decomposed by heating. if the mass loss is 0.275g, the mass percentage of KHCO₃ is 70.4%.

<h3>What is a decomposition reaction?</h3>

A decomposition reaction can be defined as a chemical reaction in which one reactant breaks down into two or more products.

Step 1: Write the balanced equation for the decomposition of KHCO₃.

2 KHCO₃(s) → K₂CO₃(s) + CO₂(g) + H₂O(l)

The mass loss of 0.275 g is due to the gaseous CO₂ that escapes the sample.

Step 2: Calculate the mass of KHCO₃ that formed 0.275 g of CO₂.

In the balanced equation, the mass ratio of KHCO₃ to CO₂ is 200.24:44.01.

0.275 g CO₂ × 200.24 g KHCO₃/44.01 g CO₂ = 1.25 g KHCO₃

Step 3: Calculate the mass percentage of KHCO₃ in the sample.

There are 1.25 g of KHCO₃ in the 1.775 g sample.

%KHCO₃ = 1.25 g/1.775 g × 100% = 70.4%

A 1.775g sample mixture of KHCO₃ is decomposed by heating. if the mass loss is 0.275g, the mass percentage of KHCO₃ is 70.4%.

Learn more about decomposition reactions here: brainly.com/question/14219426

7 0

2 years ago

6. A father rabbit had long ears while the mother rabbit had short ears. Which of these statements

Gnoma [55]

Answer:

D if I’m correct

Explanation:

8 0

3 years ago