The radius of a platinum atom is 139 pm. How many platinum atoms would have to be laid side by side to span a distance of 1.39 mm?

Answer:

The two carbon atoms share a total of six electrons with each other.

Explanation:

Looking at the structure of the molecule H-C≡C-H as shown in the question, we will notice that there exists a triple bond between the two carbon atoms.

Each bond between the two carbon atoms represents two electrons shared. Since there are three bonds between the two carbon atoms, then a total of six electrons were shared between the two carbon atoms hence the answer chosen above.

The pressure of hydrogen gas is 607.7 mmHg

According of Dalton's law of Partial pressure, the total pressure of a mixture of gases is the sum of the partial pressures of the individual gases in the mixture.

We can now write;

The for hydrogen collected over water, we have a mixture of hydrogen gas and water vapour.

Total pressure = pressure of hydrogen gas + vapour pressure of water

Pressure of hydrogen gas = Total pressure - vapour pressure of water

Pressure of hydrogen gas =  636 mmHg - 28.3 mmHg

Pressure of hydrogen gas = 607.7 mmHg

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Answer:

Electro positivity increases down the group

Explanation:

The mass of bromine is 79.904, and since there are two of them in the Calcium Bromide molecule, we'll multiply it by 2 to get 159.808. Dividing that by the full mass of the molecule then multiply it by 100 will give you the answer.

We know

[tex]\boxed{\Large{\sf M_1V_1=M_2V_2}}[/tex]

[tex]\\ \Large\sf\longmapsto M_2=\dfrac{M_1V_1}{V_2}[/tex]

[tex]\\ \Large\sf\longmapsto M_2=\dfrac{3(75)}{250}[/tex]

[tex]\\ \Large\sf\longmapsto M_2=\dfrac{225}{250}[/tex]

[tex]\\ \Large\sf\longmapsto M_2=0.9M[/tex]

Answer:

Mass 1=3M

Mass 2=?

Volume1=75mL

Volume2=250mL

By using molarity formula:

mass1*volume 1=mass2*volume 2

3M*75=mass2*250

mass2=225/250

mass2:0.9M

Answer:

gamma ray

Explanation:

Answer:

Solar heating of the Earth's surface is uneven because land heats faster than water, and this causes air to warm, expand and rise over land while it cools and sinks over the cooler water surfaces.This differential heating is passed on to the air above by conduction which causes air expansion and changes in pressure.

Data obtained from the question

NaNO₃ + H₂SO₄ —> NaHSO₄(s) + HNO₃ ΔH° = 21.2 KJ

Determination of the mass of NaNO₃ that was converted from the balanced equation.

Molar mass of NaNO₃ = 23 + 14 + (16×3)

= 23 + 14 + 48

= 85 g/mol

Mass of NaNO₃ from the balanced equation = 1 × 85 = 85 g

Thus, 85 g of NaNO₃ were converted from the balanced equation.

Determination of the heat absorbed by converting 100 g of NaNO₃.

From the balanced equation above,

When 85 g of NaNO₃ were converted, 21.2 KJ were absorbed by the system.

Thus, the conversion of 100 g of NaNO₃ will cause the system to absorb = [tex]\frac{100 * 21.2}{85} =[/tex] 24.9 KJ of heat energy.

Therefore, the system will absorb 24.9 KJ of heat energy.

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The correct order of the substances in order of decreasing boiling point is,

KF , CH30OH , CO2 , Ne

Boiling point, the temperature at which the force exerted by the surroundings upon a liquid exists equaled by the pressure exerted by the vapor of the liquid; under this situation, the addition of heat affects the transformation of the liquid into its vapor without increasing the temperature.

The main difference between the boiling point and the melting point stands that the melting point is determined as the temperature at which solid and liquid phases exist in equilibrium, whereas the boiling point stands as the temperature at which the vapor pressure of a liquid stands equal to the external pressure.

Hence, The correct order of the substances in order of decreasing boiling point is,

KF , CH30OH , CO2 , Ne

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60 I think bcz if there is 1&2 they differ 10 times

The milk has a pH of 6.0 and household ammonia has a pH of 12.0. then milk will be 6 times milk acidic than ammonia.

The pH scale, which previously stood for "potential of hydrogen," would be used to describe how acidic or basic an aqueous solution is.

More hydrogen ions are present in an acidic solution than it was in pure water.

It is given then,

[tex](milk)pH_{1} = 6\\(ammonia)pH_{2} = 12[/tex]

The concentration of hydrogen ions can be calculated by using the formula:

[tex][H^{+}] = 10^{-pH}[/tex]

By putting the value of given data in the above equation.

[tex][H^{+}_{milk} ] / H^{+}_{ammonia}= 10^{-6}/10^{-12}\\ = 10^{6} = 6[/tex]

We get that, milk will be 6 times more acidic than ammonia.

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Answer:

C

Explanation:

If he can't read his computer screen. Means his eyes have problem

A new member of your team is visually impaired. He's having a hard time reading his computer screen.  value diversity require computer usage. 12 Tell him that he might want to schedule an eye exam. Therefore, option C is correct.

Institutions and community members who value diversity do so in order to recognize the advantages of both their differences and commonalities. They make a deliberate effort to forge enduring connections between individuals and organizations with a broad membership.

When people's unique qualities, abilities, interests, and viewpoints are recognized and supported, they develop a stronger sense of self and health and achieve better results in their academic and professional endeavors.

Although diversity and inclusion are related ideas, they are not the same thing. Diversity has to do with representation or how something is put together. The degree to which the contributions, presence, and viewpoints of other groups of individuals are appreciated and incorporated into a setting is referred to as inclusion.

Thus, option C is correct.

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Answer:

-401.06 atm

Explanation:

Applying,

P = (nRT/V-nb)-(an²/V²)............... Equation 1

Where P = Pressure, R = Universal gas constant, V = molar Volume, T = Temperature in Kelvin, a = gas constant a , b = gas constant b, n = numbers of mole

From the question,

Given: T = 299.8 K, V = 0.8006 L, a = 2.318 L.atm/mol, b = 3.978×10²L/mol

Constant: R = 0.0082 atm.dm³/K.mol

Substitute these values into equation 1

P = [(0.0082×299.8×10.53)/(0.8006-(10.53×397.8)]-[(10.53²×2.318/0.8006²)]

P = (25.89/-4188.0334)-(400.995)

P = -0.0618-400.995

P = -401.06 atm

Answer:

I think its A maybe am not sure

Answer:

a. Endothermic.

b. [tex]Q_{rxn}=5493.6J[/tex]

c. [tex]\Delta H_{rxn}=35.0kJ/mol[/tex]

Explanation:

Hello there!

In this case, according to the given information for this calorimetry problem, it turns out possible for us to proceed as follows:

a. Due to the fact that the temperature of water goes from 23.0 °C to 18.0 °C, we infer this reaction is endothermic as the ammonium nitrate absorbed heat from the water.

b. Here, we consider the following heat equation:

[tex]Q_{rxn}=-Q_{water}[/tex]

Whereas we solve for the heat of reaction by means of the mass of the solution (both water and ammonium nitrate), the specific heat of the solution (we assume it is equal to that of water) and the temperature change:

[tex]Q_{rxn}=-m_{solution}C_{solution}(T_f-T_i)\\\\Q_{rxn}=-(12.6g+250.g)(4.184\frac{J}{g\°C} )(18.0\°C-23.0\°C)\\\\Q_{rxn}=5493.6J[/tex]

c. Here, we divide the previously calculated heat by the moles of ammonium nitrate (molar mass = 80.043 g/mol) to obtain the enthalpy of reaction per mole of this compound:

[tex]n_{NH_4NO_3}=12.6g*\frac{1mol}{80.043 g}=0.157mol\\\\\Delta H_{rxn}=\frac{5493.6J}{0.157mol} =34898.7J/mol\\\\\Delta H_{rxn}=35.0kJ/mol[/tex]

Regards!

Answer:

Alpha and beta particles originate from the nucleus, protection from radiation is important because if the radiation passes through the body it can damage cells. Exposure to radiation is often limited by increasing the distance from the radioactive source.

Explanation:  

Explanation:

The given data is:

The mass of hydrogen is 6.54 kg.

The actual yield is 30.4 kg.

The balanced chemical equation of the reaction is:

[tex]N_2(g)+3H_2(g)<=>2NH_3(g)[/tex]

At first the theoretical yield should be calculated by using the balanced chemical equation:

3 mol. of hydrogen forms ---- 2 mol. of ammonia.

The molar mass of hydrogen is 2.0 g/mol.

The molar mass of ammonia is 17.0 g/mol.

Hence, the above statement can be rewritten as:

6g of hydrogen forms --- 34g of ammonia.

Then,

6.54g of hydrogen forms :

[tex]6.54 kg x 34 g / 6 g\\=37.1 kg[/tex]

% yield = (actual yield /theoretical yield )x 100

=(30.4 kg /37.1 kg )x100

=81.9

Hence, % yield is 81.9.

Suppose you have a material in it's liquid phase. As you give energy to that liquid, the temperature of the liquid will increase gradually, and the relation between the increase of temperature and the given energy is the specific heat.

Now, there is a point, a critical point, where the temperature stops to increase, which means that we are near a change of phase. So from this point on, the energy is not used to increase the kinetic energy of the particles (which would increase the temperature), the energy is used to break the bonds and allow a change of phase, for example, from liquid to gas.

So, we know that if you have a mol of water at 100°C, then you need to add 40.7 kJ of energy to change the phase of the water from liquid to gas phase.

This means that if you have a mol of water and you give that exact energy, the temperature will not change, instead, you now will have a mol of water at the temperature of 100°C.

Similarly with the case at 25°C (which happens for a particular pressure only)

So the heat of vaporization can not really be related to increases in temperature as you thought.

For changes in temperature, you need to use the specific heat.

We know that for water it is:

c = 4.184 J/g*°C = 76.15 J/mol*°C

So, if you want to increase the temperature from 25° to 100°

This means an increase of 75°C of one mol of water.

We just need to multiply the above number by:

1mol*(75°C)

Energy needed = (76.15 J/mol*°C)*1mol*(75°C) = 5,711.25 J

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Answer:

12

Explanation:

2+8+2=12

atomic no is the No of protons

Answer:

Atomic number is 12.

Explanation:

Atomic number = electrons in filled shells + outermost electrons

= 2 + 8 +2

= 12

Your answer is CaO.I hope that my answer helped you..

Answer:

C

Oxygen gas is limiting.

C(s) + O

2

→CO

2

(g)

No. of moles of carbon =

12

36

=3 moles

No. of moles of oxygen =

32

32

=1 moles

So, 2 moles of carbon is left and oxygen will be completed.

So, O

2

is limiting reagent.

Answer:

14.5

Explanation:

not sure how I got it but I hope this helped!

Answer:

Sodium dihydrogenphosphate = NaH₂PO₄

Sodium monohydrogenphosphate = Na₂HPO₄

Explanation:

A buffer solution is a solution is a solution that resists changes to its oH when a little quantity of strong acid or strong base is added to it.

They are solutions of weak acids or weak bases and their salts known as conjugate base or conjugate acids respectively for the weak acids and weak bases.

For example, a solution of the weak acid ethanoic acid and its salt or conjugate base, sodium ethanoate serves as a buffer solution.

In biochemical experiments, where the pH of the reaction medium is kept as constant and as close as possible to that of the internal environment, buffer solutions are widely used. One of the commonly used buffers is the phosphate buffer. The phosphate buffer consists of the acid salts sodium dihydrogenphosphate and sodium monohydrogenphosphate. Sodium dihydrogenphosphate serves as the weak acid while sodium monohydrogenphosphate serves as the conjugate base.

The formulas of these two compounds are given below:

Sodium dihydrogenphosphate = NaH₂PO₄

Sodium monohydrogenphosphate = Na₂HPO₄

Answer:

TATGGCGTT

Explanation:

Complimentary base pairs:

A-T

C-G

Use the other letter for complimentary strands

Answer:

D. One soluble and one insoluble salts are formed

Explanation:

Explanation:

b. Bromo cyclopentane + HBr

Answer:

[tex]\boxed {\boxed {\sf -2}}[/tex]

Explanation:

We are asked to find the net charge of an ion.

The ion has 14 protons, 16 electrons, and 12 neutrons. Recall the charges of each subatomic particle.

Neutrons are neutral and have no charge, so we can ignore them while finding the net charge. There are 14 protons and 16 electrons.

14 protons and 14 electrons have a net charge of 0 because the charges balance each other out. However, we have 16 electrons, which is 2 more than 14. Each electron has a charge of -1, so the 2 electrons add a charge of -2.

The net charge of the ion is -2.

Answer:

See explanation and image attached

Explanation:

The reaction of (R)-2-chloro-3-methylbutane with potassium tert-butoxide yields a monosubstituted alkene .

Since the base is bulky, the Hoffman product predominates because attack occurs at the less hindered carbon atom to yield the major product as shown.

The alkene reacts with HBr at the secondary carbon atom to yield a carbocation intermediate which is flat and planar. Attack on either face of the carbocation yields a racemic mixture of the (2R) and (2S) products.

Rearrangement of the carbocation to yield a tertiary carbocation gives the 2-bromo-2-methyl butane product as shown in the image attached.

Answer:

catenation

Explanation:

Carbon atoms have four electrons to share in bonding environments to get to the ideal octet. To do this, it bonds with other carbon molecules, called catenation. Catenation is the ability of an atom to bond and share electrons with other atoms of its kind.

In this figure, four shapes contains the same text as in the red oval. The text given in the red oval is KTKEIHLPEQMKJAPDEK.

Shape is "the form of an object or its outline, outer boundary or outer surface".

Text is "a collection of words or letters that are understandable by the reader".

Oval is a rounded and slightly elongated outline or shape like that of an egg.

Hence, four shapes contains the same text as in the red oval.

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Answer:

3,29L

Explanation:

3.29L = V2

Formula: V1/T1 = V2/T2

--------------------

Given:

V1 = 3.0 L V2 = ?

T1 = 310 K T2 = 340 K

--------------------

Plugin:

(X stands in place of V2 just to make it easier to look at)

[3.0L / 310K = X / 340K]

(3.0L / 310K = 0.01L/K)

0.01L/K = X / 340K

(multiply 340K on both sides, it cancels out on the right)

0.01L/K * 340K = X

(0.01L/K * 340K = 3.29L)

**3.29L = X**

[or]

**3.29L = V2**