Tungsten (W) and chlorine (Cl) form a series of compounds with the following compositions:_______.
Mass % W Mass % Cl
72.17 27.83
56.45 43.55
50.91 49.09
46.36 53.64
If a molecule of each compound contains only one tungsten atom, what are the formulas for the four compounds?

Answer:

Ecological islands is just a terminology used, since it isn't surrounded by water like an actual island, instead, it's something isolated from other things, which is the same thing as an island in a way:

Island (geographical) - Land isolated from bigger "main" land masses by water.

Island (ecological) - Land which contains certain isolated features (habitat, plants, etc.).

Explanation:

An ecological island is an area of land, isolated by natural or artificial means from its surrounding land while geographical islands are a body of land surrounded by water.

An ecological island refers to an area of land which is not necessarily an actual island but isolated by natural or artificial means from the surrounding land. A natural micro-habitat exists on sich lands amidst a larger differing ecosystem.

In artificial ecological islands, all non-native species are eradicated, native species are reintroduced and nurtured, and the natural or artificial border is maintained to prevent the reintroduction of non-native species.

A geographical island is a body of land surrounded by water. Continents are also surrounded by water as they are so big but they are not considered islands. Islands may be categorized as either continental or oceanic.

There are so many islands in the lakes, oceans, and rivers around the world. They vary in climate, size, and the types of organisms that inhabit them.

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Answer: [tex]Pb(NO_3)_2(aq)+2NaOH(aq)\rightarrow 2NaNO_3(aq)+Pb(OH)_2(s)[/tex]

Explanation:

A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.

The balanced chemical equation for a precipitate forms when aqueous solutions of lead(II) nitrate and sodium hydroxide are combined is:

[tex]Pb(NO_3)_2(aq)+2NaOH(aq)\rightarrow 2NaNO_3(aq)+Pb(OH)_2(s)[/tex]

Answer:

i wish i could help but t know either so i wish you luck for an answer once again truly sorry don'

Explanation:

i am sorry but i do not know :(

Answer:

The frequency is  [tex]f =  2,01 * 10^{15} \  Hz  [/tex]

Explanation:

From the question we are told that

   The energy required to ionize boron is [tex]E_b  =  801 KJ/mol[/tex]

Generally the ionization energy of boron pre atom is mathematically represented as

     [tex]E_a  =  \frac{E_b}{N_A}[/tex]

Here  [tex]N_A[/tex] is the Avogadro's constant with value [tex]N_A  =  6.022*10^{23}[/tex]

So

      [tex]E_a  =  \frac{801}{6.022*10^{23}}[/tex]

=>     [tex]E_a  =  1.330 *10^{-18} \  J/atom [/tex]

Generally the energy required to liberate one electron from an atom is equivalent to the ionization energy per atom and this mathematically represented as

       [tex]E =  hf  =  E_a[/tex]

=>     [tex]  hf  =  E_a[/tex]

Here h is the Planks constant with value [tex]h = 6.626 *10^{-34}[/tex]

So

       [tex]f =  \frac{1.330 *10^{-18}}{ 6.626 *10^{-34}}[/tex]

=>      [tex]f =  2,01 * 10^{15} \  Hz  [/tex]

Answer:

I think it's A and D

Explanation:

I'm not sure if it's right

Answer:

The answer is B and D

Explanation:

trust fr

Answer:

Hypothesis: IF a penny is dropped from a building, THEN it would kill a pedestrian below

Controls: Same building, Same distance

Independent variable: Penny

Dependent variable: Pedestrian's death

Conclusion: The hypothesis is rejected

Explanation:

- The hypothesis is a testable explanation to an observed problem or asked question. Based on the cientific question in this question, a possible hypothesis will be: IF a penny is dropped from a building, THEN it would kill a pedestrian below

- Independent variable is the variable that is changed or manipulated in an experiment. In this case, the PENNY is the independent variable

- Dependent variable is the variable that responds to the change made to the independent variable. It is the measured variable. In this case, the dependent variable is the DEATH OF PEDESTRIANS.

- Controls are those variables that is kept constant or unchanged throughout the experiment. The controls in this experiment are: Same building, Same distance of throw etc.

- The conclusion is whether the hypothesis is accepted or not depending on the result of the experiment conducted. In this case, the hypothesis will be rejected if the penny doesn't kill a pedestrian

Answer:

The molecules in the liquid are moving past one another. The hydrogen end of one water molecule is attracted to the oxygen end of another but only for a short time because they are moving. The molecules in ice are further apart than in liquid water. The molecules in ice are in fixed positions but still vibrate.

Explanation:

-google

Answer:

Explanation:

The new volume can be found by using the formula for Boyle's law which is

[tex]P_1V_1 = P_2V_2[/tex]

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

Since we are finding the new volume

[tex]V_2 = \frac{P_1V_1}{P_2} \\[/tex]

We have

[tex]V_2 = \frac{300 \times 2}{7} = \frac{600}{7} \\ = 85.714285...[/tex]

We have the final answer as

Hope this helps you

Answer:

Molarity = 1.4 M

Explanation:

Given data:

Mass of LiCl = 15.25 g

Volume of solution = 250 mL (250/1000 = 0.25 L)

Molarity of solution = ?

Solution:

Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.

Formula:

Molarity = number of moles of solute / L of solution

Now we will calculate the number of moles of LiCl.

Number of moles = mass/molar mass

Number of moles = 15.25 g/ 42.39 g/mol

Number of moles = 0.36 mol

Molarity:

Molarity = 0.36 mol / 0.25 L

Molarity = 1.4 M           (M= mol/L)

Ideal gas law is valid only for ideal gas not for vanderwaal gas. Therefore, value of the gas constant R is 0.0821LatmK⁻¹ when volume is 0.0413 L.

Ideal gas equation is the mathematical expression that relates pressure volume and temperature.

Mathematically the relation between Pressure, volume and temperature can be given as

PV=nRT

where,

P = pressure of nitrogen gas = 0.991 atm

V= volume of nitrogen gas =0.0413 L

n =number of moles of nitrogen gas = given mass ÷Molar mass

                                                          =0.0451 g ÷28

                                                          =0.0016mol

T =temperature of nitrogen gas =298 K

R = Gas constant =?

0.991 atm×0.0413 L=0.0016×R×298 K

R=0.0821LatmK⁻¹

Therefore, value of the gas constant R is 0.0821LatmK⁻¹.

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Answer: The mass of blue copper sulfate is 3.5 g

Explanation:

Law of conservation of mass states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.

This also means that total mass on the reactant side must be equal to the total mass on the product side.

The chemical equation for the heating of copper sulfate crystals is:

Let the mass of blue copper sulfate be 'x' grams

We are given:

Mass of copper sulfate powder = 2.1 grams

Mass of water = 1.4 grams

Total mass on reactant side = x

Total mass on product side = (2.1 + 1.4) g

So, by applying law of conservation of mass, we get:

Hence, the mass of blue copper sulfate is 3.5 grams

Answer:

it is Calcium (Ca)

4th period, 2nd group, 2 valence electrons

Answer:

c,a,b,d

Explanation:

Answer:

[tex]a=\frac{f}{d-e}-\frac{b}{c}[/tex]

Explanation:

Hello.

In this case, for the equation:

[tex](a+b/c)(d-e)=f[/tex]

For isolating a, we must first pass (d-e) to divide at the other side as it is initially multiplying:

[tex]a+b/c=\frac{f}{(d-e)}[/tex]

Next, as b/c is adding, it passes to subtract at the other side in order to finally isolate a:

[tex]a=\frac{f}{d-e}-\frac{b}{c}[/tex]

Best regards!

Answer:

x = 33.52 amu

Explanation:

It is given that,

Isotope A has a mass of 34 amu and an abundance of 52%, isotope B has a mass of 33 amu and an abundance of 48%.

Let x is the average atomic mass of this element. It can be calculated as follows :

[tex]x=52\%\ \text{of}\ 34+48\%\ \text{of}\ 33\\\\x=\dfrac{52}{100}\times 34+\dfrac{48}{100}\times 33\\\\x=0.52\times 34+0.48\times 33\\\\x=33.52\ \text{amu}[/tex]

So, the average atomic mass of this element is 33.52 amu.

Answer: The molar mass of the unknown gas  is 9 g/mol

Explanation:

From Graham's law of effusion rates, the rate of effusion of a gas is inversely proportional to the square root of its molar mass.

[tex]\frac{rate_1}{rate_2}=\sqrt{\frac{M_2}{M_1}} [/tex]

[tex]rate=\frac{volume}{time} [/tex]

Rate is volume effused per unit time. Since, the volumes are same, the formula could be written as:

[tex]\frac{t_B}{t_A}=\sqrt{\frac{M_B}{M_A}}[/tex]

Putting the values in the formula:

[tex]\frac{2.42min}{11.1min}=\sqrt{\frac{M_{H_2}}{M_A}} [/tex]

[tex]\frac{2.42min}{11.1min}=\sqrt{\frac{2}{M_A}} [/tex]

Squaring both sides:

[tex]\frac{2}{M_A}=0.218[/tex]

[tex]M_A=9g/mol[/tex]

The molar mass of the unknown gas  is 9 g/mol

Dull black surface are good absorbers of radiation.

The process by which energy in the form of electromagnetic radiation is emitted by a heated surface and travels directly to its absorption point at the speed of light.

The rate at which a body absorbs or radiates thermal radiation relies upon the nature of the surface as well.

According to the Kirchhoff's radiation law, the objects, which are good emitters are also good absorbers.

A blackened surface is an excellent absorber as well as an excellent emitter.

A black body refers to a body, which is regarded as a perfect radiator and absorber of electromagnetic radiations, a dull black surface is a good absorber of heat radiation.

Thus, dull black surface is the best surface for absorbing heat radiation.

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Answer:

a. 0.183 mol C

b. 0.366 mol H

Explanation:

Assuming total combustion, all of the carbon in the unknown compound turned into carbon dioxide, CO₂.

So first we calculate the CO₂ moles produced, using its molecular weight:

This means in the unknown compound there were 0.183 moles of carbon, C.

Conversely, all of the hydrogen in the unknown compound turned into water, H₂O.

Calculating the H₂O moles:

We multiply the water moles by two, as there are 2 H moles per H₂O mol:

Answer:

92.75%

Explanation:

The overall chemical equation for the reaction in the preparation of alum from the aluminium can be expressed as:

[tex]\mathtt{2Al + 2KOH + 4H_2SO_4 +2H_2O \to 2KAl(SO_4)_2 2H_2O +3H_2}[/tex]

From above; we will see that 2 moles of Aluminium react with sulphuric acid and water to produce 2 moles o aluminium alum.

Therefore, the theoretical yield can be determined as:

[tex]=0.4395 \ g Al \times \dfrac{1 \ mol \ Al}{27 \ g Al }\times \dfrac{2 \ mol \ KAl(SO_4)_2}{2 \ mol \ Al}\times \dfrac{294.23 \ KAl(SO_4)_2}{1 \ mol \ KAl(SO_4)_2}[/tex]

= 4.789g of [tex]KAl(SO_4)_2[/tex]

To find the percent yield, we need to divide the actual yield by the theoretical yield and then multiply it with 100.

∴

percent yield = ( mass of alum(g)/theoretical yield(g) ) × 100

percent yield = ( 4.789g / 5.1629g ) × 100%

percent yield = 0.9275 × 100%

percent yield = 92.75%

Thus, the percent yield of the experiment 92.75%

Answer:

2.35 x 10²⁰ atoms Ga

Explanation:

After converting from mg to g, use the molar mass as the unit converter to convert to moles. Then using Avogadro's number, 6.022 x 10²³ convert from moles to atoms of Ga.

[tex]27.2mgGa*\frac{1g}{1000mg} *\frac{1 mol Ga}{69.72gGa} *\frac{6.022*10^2^3 atoms Ga}{1 molGa} = 2.349 * 10^2^0 atoms Ga[/tex]

Then round to 3 significant figures = 2.35 x 10²⁰ atoms Ga.

The number of atoms in 27.2 mg sample of Ga is 2.35 × 10²⁰ atoms

From the question, we are to calculate the number of atoms in a 27.2 mg sample of Ga.

First, we will determine the number of moles of Ga present

Using the formula,

[tex]Number\ of\ moles = \frac{Mass}{Molar\ mass} [/tex]

Mass = 27.2 mg = 0.0272 g

Molar mass = 69.72 g/mol

Then,

[tex]Number\ of\ moles \ of\ Ga = \frac{0.0272}{69.72} [/tex]

[tex]Number\ of\ moles \ of\ Ga = [/tex] 0.000390132 moles

Now, for the number of atoms present

From the formula

Number of atoms = Number of moles × Avogadro's constant

Then,

Number of Ga atoms = 0.000390132 × 6.022×10²³

Number of Ga atoms = 2.35 × 10²⁰ atoms

Hence, the number of atoms in 27.2 mg sample of Ga is 2.35 × 10²⁰ atoms

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Answer:

XH₂ = 0.4885

XN₂ = 0.4290

XAr = 0.0825

Explanation:

Step 1: Given data

Step 2: Calculate the total pressure (P)

The total pressure is equal to the sum of the partial pressures of all the gases.

P = pH₂ + pN₂ + pAr = 441.0 Torr + 387.3 Torr + 74.5 Torr = 902.8 Torr

Step 3: Calculate the mole fraction (X) of each gas

We will use the following expression.

Xi = pi / P

where,

Xi: mole fraction of the gas i

pi: partial pressure of the gas i

P: total pressure

XH₂ = pH₂ / P = 441.0 Torr / 902.8 Torr = 0.4885

XN₂ = pN₂ / P = 387.3 Torr / 902.8 Torr = 0.4290

XAr = pAr / P = 74.5 Torr / 902.8 Torr = 0.0825

Answer:

NaCl(aq)

Explanation:

Nacl(aq) is an electrolyte when it melts and it conducts electricity. This is due to the fact that when it is in solution, it dissociates to be Na+ and Cl-. These ions are conductors of electricity. It conducts electricity because of the movements and also the discharge of ions. CH3OH(aq) is not a conductor of electricity therefore the first option is the answer.

Answer:

Potassium chloride, KCl , is an ionic compound formed by the electrostatic force of attraction that holds the potassium cations and the chlorine anions together

Explanation:

Answer:

Explanation:

Significant figure implies number of digits that are to be considered. Some rules are required to be considered when writing a given expression to an expected significant figures.

So that:

1) 0.00004050 is 4 significant figures

2) 54.7000 is 6 significant figures

3) 1,000.09 is 6 significant figures

4) 0.039 is 2 significant figures

Answer:

See explanation

Explanation:

When the temperature was increased, the pressure of the gas in the can was increased.

When Maria removed the can and placed it in cold liquid, the decrease in temperature led to a corresponding decrease in pressure of the gas inside the can hence the can was crushed.

Hypothesis: The pressure of the gas in the can is directly proportional to temperature.

Maria was careless about the experiment. She ought to have first checked whether the hot plate was off before placing the soda can. Secondly,she should not have immediately plunged the soda can into liquid because it will shrink due to decrease in pressure. She should not also have removed the soda can with bare hands to avoid getting burns and blisters.

Answer:

You feel warm when you stand near a campfire because the flames of the fire warm your body. The heated waves are hit towards you and your body feels warm.

Hope this helped :)

Explanation:

Answer:

4

Explanation:

24/6 is 4.

Answer:

Mathematically: D = m/v. If you know what liquid you have, you can look up its density in a table. Once you know that, all you have to do to find the mass of the liquid is to measure its volume. Once you know density and volume, calculate mass using this relationship: mass = density • volume.

Explanation:

Answer:

Silver.

Explanation:

Hello!

In this case, we can consider the specific heat as the property that we can analyze in order to answer to this question. In such a way, as the specific heat is known as the energy required to modify the temperature of 1 g of the substance by 1 °C, since the masses of all the substances are the same, we can that their specific heats are respectively 0.240, 0.444 and 4.184 J/(g°C), from the equation:

[tex]Q=mCp\Delta T[/tex]

We can see that the higher the specific heat (Cp) the lower the change in temperature considering their inversely proportional relationship. However, as 100 J of energy is applied to all the substances, we can see that silver will exhibit the largest temperature change because a higher change is needed to fit with the provided energy.

Best regards.

Answer:

Exothermic

Explanation:

Nuclear fission means splitting, so there is a lot of energy being released.

Calcium (Ca) is in group 2 and period 4 on the periodic table be because Calcium has 2 valence electrons and 4 electron shell. Thus, calcium is a metal like all other group 2 element.

The correct answer to the question is Option C. Calcium, like all group 2 elements, is reactive and a solid at room temperature.

Calcium is a group 2 element majorly because it has 2 valence electrons. It is also in period 4 because it has 4 electron shells.

Being a group 2 element, calcium is a solid at room temperature and also reactive. All elements in the group 2 are metals.

There are other elements in period 4 which are not solid. For example krypton is an element in period 4 and it is a gas and not reactive.

From the above information, we can conclude that the correct answer to the question is:

Option C. Calcium, like all group 2 elements, is reactive and a solid at room temperature.

See attached image

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