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tiny-mole [99]
3 years ago
11

Classify each of these statements as always true, AT, sometimes true, ST, or never true, NT. _____ 1. A mole of a pure substance

contains 6.02 x 1023 atoms. _____ 2. The representative particle of a compound is a molecule. _____ 3. A mole of CCl4 is composed of one atom of carbon and 4 atoms of chlorine. _____ 4. One mole of gas occupies 22.4 L _____ 5. The formula of methane is CH4. If methane contains 75% carbon, then 100 grams of methane contains 25 grams of carbon. _____ 6. The formula for methane CH4 is both an empirical and molecular formula. _____ 7. The empirical formula of C6H12O6 is C2H4O2.
Chemistry
1 answer:
poizon [28]3 years ago
8 0

Answer:

1. AT

2. NT

3. AT

4. ST

5. NT

6. AT

7.ST.

Explanation:

1. AT

This is so because a mole of a pure substance contains that number of atoms at any point in time. The only criterion needed there is if the compound is pure or not.

2. NT.

3.AT

IN CCl4, we have one atom of carbon and 4 atoms of chlorine.

4. ST

This is only true in some instances and not at all times. The relation is only true at s.t.p. It does not hold at other conditions which are not s.t.p

5. NT

Methane contains 75% carbon. It is only right that 100gm methane would contain more than what the hydrogen would have as it has a higher percentage by mass and hence the 25gm is wrong.

6. AT

YES. The molecular formula of methane is also it's empirical formula

7. ST

This is not always true as we have more than one way in which the outside multiple n can multiply the inner numbers to yield the molecular formula. In the case quoted above, n = 3. Analysis can also show that n = 6 in which case the empirical formula would be CH2O.

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solmaris [256]
The shape of the H2O molecule is a Bent Triatomic.
It isn't symmetrical.
The H2O molecule is polar.
6 0
3 years ago
Read 2 more answers
Which reactions are single displacement reactions? 2NaBr + CaF2 → 2NaF + CaBr2 SnO2 + 2H2 → Sn + 2H2O 4Na + O2 → 2Na2O 2KClO3 →
r-ruslan [8.4K]

Answer : The correct options are, SnO_2+2H_2\rightarrow Sn+2H_2O and 2Al+6HCl\rightarrow 2AlCl_3+3H_2

Explanation :

Single displacement reaction : It is a type of chemical reaction in which the more reactive element displaces the less reactive element.

Option A reaction : 2NaBr+CaF_2\rightarrow 2NaF+CaBr_2

It is an example of double displacement reaction because in this reaction a positive cation and a negative anion of the two reactants exchange their places to form two new products.

Option B reaction : SnO_2+2H_2\rightarrow Sn+2H_2O

It is an example of single displacement reaction.

Option C reaction : 4Na+O_2\rightarrow 2Na_2O

It is an example of combination reaction because in this reaction two reactants react to give a single product.

Option D reaction : 2KClO_3\rightarrow 2KCl+3O_2

It is an example of decomposition reaction because in this reaction a single reactant decomposes into two or more products.

Option E reaction : 2Al+6HCl\rightarrow 2AlCl_3+3H_2

It is an example of single displacement reaction because in this reaction the most react element, aluminium displaces the less reactive element, hydrogen.

Hence, the options B and E are single displacement reactions.

5 0
3 years ago
Titanium has an HCP crystal structure, a c/a ratio of 1.669, an atomic weight of 47.87 g/mol, and a density of 4.51 g/cm3. Compu
IrinaK [193]

Answer : The atomic radius for Ti is, 1.45\times 10^{-8}cm

Explanation :

Atomic weight = 47.87 g/mole

Avogadro's number (N_{A})=6.022\times 10^{23} mol^{-1}

First we have to calculate the volume of HCP crystal structure.

Formula used :  

\rho=\frac{Z\times M}{N_{A}\times V} .............(1)

where,

\rho = density  = 4.51g/cm^3

Z = number of atom in unit cell (for HCP = 6)

M = atomic mass  = 47.87 g/mole

(N_{A}) = Avogadro's number  

V = volume of HCP crystal structure = ?

Now put all the values in above formula (1), we get

4.51g/cm^3=\frac{6\times (47.87g/mol)}{(6.022\times 10^{23}mol^{-1}) \times V}

V=1.06\times 10^{-22}cm^3

Now we have to calculate the atomic radius for Ti.

Formula used :

V=6R^2c\sqrt{3}

Given:

c/a ratio = 1.669 that means,  c = 1.669 a

Now put (c = 1.669 a) and (a = 2R) in this formula, we get:

V=6R^2\times (1.669a)\sqrt{3}

V=6R^2\times (1.669\times 2R)\sqrt{3}

V=(1.669)\times (12\sqrt{3})R^3

Now put all the given values in this formula, we get:

1.06\times 10^{-22}cm^3=(1.669)\times (12\sqrt{3})R^3

R=1.45\times 10^{-8}cm

Therefore, the atomic radius for Ti is, 1.45\times 10^{-8}cm

3 0
3 years ago
Consider the reaction below. Initially the concentration of SO2Cl2 is 0.1000 M. Solve for the equilibrium concentration of SO2Cl
tensa zangetsu [6.8K]

Answer:

[SO_2Cl_2] = 0.09983 M

Explanation:

Write the balance chemical equation ,

SO_2Cl_2((g) = SO_2(g) + Cl_2(g)

initial concenration of SO_2Cl_2((g)  =0.1M

lets assume that degree of dissociation=\alpha

concenration of each component at equilibrium:

[SO_2Cl_2] = 0.1-0.1\alpha

[SO_2] = 0.1\alpha

[Cl_2] = 0.1\alpha

Kc =\frac{0.1\alpha \times 0.1\alpha}{0.1-0.1\alpha}

Kc =\frac{0.1\alpha \times \alpha}{1-\alpha}

as \alpha is very small then we can neglect  1-\alpha

therefore ,

Kc ={0.1\alpha \times \alpha}

\alpha =\sqrt{\frac{Kc}{0.1}}

\alpha = 1.73 \times 10^{-3}

Eqilibrium concenration of [SO_2Cl_2] = 0.1-0.1\alpha = 0.1-0.1\times 0.00173

[SO_2Cl_2] = 0.09983 M

4 0
3 years ago
How are the parts of a wave related? Describe it and include the formula
KonstantinChe [14]

Different parts of wave include Amplitude,wavelength,period,frequency,time-period,speed,velocity .

Explanation:

Waves are one way in which energy may be transferred. Both mechanical and electromagnetic waves will transfer energy.

When a wave is drawn on a graph  the vertical axis is the amplitude of the wave while the horizontal axis can be either distance or time.

The highest point on the graph of the wave is called the crest and the lowest point is called the trough.The line through the center of the wave is the resting position of the medium if there was no wave passing through.

The different properties of a wave include:

Amplitude,wavelength,period,frequency,time-period,speed,velocity etc..

The wavelength of a wave is the distance between two two crests of a wave or two troughs of a wave. The wavelength is usually represented in physics by the Greek letter lambda (λ).  

The frequency of a wave is the number of  times per second that the wave cycles. Frequency is measured in Hertz or cycles per second and often represented by the lower case "f."  

The period of the wave is the time between wave crests. The period is measured in time units such as seconds and is usually represented by the upper case "T".  

The period and frequency are closely related to each other. The period equals  1 over the frequency and the frequency is equal to one over the period. They are reciprocals of each other as shown in the following formulas.

period = 1/frequency  or  T = 1/f

frequency = 1/period  or f = 1/T

Another important property of a wave is the speed of propagation. This is how fast the disturbance of the wave is moving. The speed of mechanical waves depends on the medium that the wave is traveling through. For example, sound will travel at a different speed in water than in air.  

The velocity of a wave is usually represented by the letter "v". The velocity can be calculated by multiplying the frequency by the wavelength.  

velocity = frequency * wavelength  or  v = f * λ

5 0
3 years ago
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