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2 years ago

Which of these statements is/are true? Rewrite each false statement to make it true.

Chemistry

2 answers:

SashulF [63]2 years ago

6 0

Answer:

Explanation:

surface tension is first defined as a surface phenomenon in which it behaves like an elastic skin. Scientifically, it can be defined as the force acting perpendicular to a surface.

calculating the molar mass of CH3Br = 12 + (1*3) + 74

= 97 g/mol

molar mass of CH3Cl = 12 + (1*3) + 35.5

=50.5 g/mol

Therefore as seen above, the mass of CH3Br is greater than the mass of CH3Cl and hence this affects their individual forces as earlier stated.

Surface tension is directly proportional to the surface energy. Surface energy basically have to do with the inter-molecular bonds within the atoms of the molecule. Cohesion is defined as attracts between molecules of a fluid when creates a net force of zero and hence cause its spherical shape. Adhesive forces are simply just the attraction of molecules of the fluid and the surface which it is found.

Organic compounds (Alkanes) like wax (paraffin wax)which have low surface energy due to its non-polar functional group and its weak dipole-dipole bonds. Therefore, water adheres weakly to the wax and strongly to its molecules hence its spherical shape

Lelechka [254]2 years ago

4 0

<h3>Answer:</h3>

TRUE- The surface tension of CH3Br is greater than the surface tension of CH3Cl.

FALSE-Water forms spherical drops on wax because the surface tension of water is greater than the adhesive forces between wax and water.

<h3>Explanation:</h3>

The statement that, the surface tension of CH3Br is greater than the surface tension of CH3Cl is true.
This is because of the fact that CH₃Br has more molar mass compared to CH₃Cl. Additionally, CH₃Br has greater dispersion forces and is more polarizable thus having greater surface tension compared to CH₃Cl.
The statement that "Water forms spherical drops on wax because the surface tension of water is greater than the adhesive forces between wax and water" is FALSE.
We would correct it by saying, Water forms spherical drops on wax because the cohesive force of water is greater than the adhesive forces between wax and water.
Cohesive forces are forces of attraction between molecules or particles of the same type while adhesive forces is a force of attraction between molecules of different type.

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As Danny was pouring cereal for his breakfast, he noticed that the cereal box says that the cereal contains 5 milligrams of iron

Vinil7 [7]

Answer:

Correct, because B it is reported to the nearest miligram

Explanation:

4.6 rounded up is 5

6 0

2 years ago

If Co(NH3)63+ has a λmax at 440 nm, calculate ΔE for the complex. A) 2.72 x 10-4 kJ/mol B) 4.52 x 10-2 kJ/mol C) 2.72 x 10 2 kJ/

riadik2000 [5.3K]

<u>Answer:</u> The energy of the complex is $2.72\times 10^2kJ$

<u>Explanation:</u>

To calculate the energy of the complex, we use the equation given by Planck which is:

$\Delta E=\frac{N_Ahc}{\lambda}$

where,

$\lambda$ = Wavelength of the complex = $440nm=4.40\times 10^{-7}m$ (Conversion factor: $1m=10^9nm$ )

h = Planck's constant = $6.624\times 10^{-34}Js$

c = speed of light = $3\times 10^8m/s$

$N_A$ = Avogadro's number = $6.022\times 10^{23}$

$\Delta E$ = energy of the complex

Putting values in above equation, we get:

$\Delta E=\frac{6.022\times 10^{23}\times 6.624\times 10^{-34}\times 3\times 10^8}{4.40\times 10^{-7}}\\\\\Delta E=2.72\times 10^{5}J=2.72\times 10^2kJ$

Conversion factor used: 1 kJ = 1000 J

Hence, the energy of the complex is $2.72\times 10^2kJ$

5 0

2 years ago

How much heat is required to raise the temperature of 670g of water from 25.7"C to 66,0°C? The specific heat

inna [77]

Answer:

Explanation:

q= mc theta

where,

Q = heat gained

m = mass of the substance = 670g

c = heat capacity of water= 4.1 J/g°C

theta =Change in temperature=( 66-25.7)

Now put all the given values in the above formula, we get the amount of heat needed.

q= mctheta

q=670*4.1*(66-25.7)

=670*4.1*40.3

=110704.1

8 0

2 years ago

The nucleus of a neutral potassium atom is "surrounded" by

ddd [48]

The answer is electron.

The nucleus of a neutral potassium atom is "surrounded" by electron.

The neutral potassium atom contains equal number of protons and neutrons, and there are 19 electrons and 19 protons while 20 neutrons.

20 protons and 20 neutrons are there in the nucleus while 19 electrons surrounds the nucleus in different orbits .

7 0

2 years ago

Read 2 more answers

If PbI2(s) is dissolved in 1.0MNaI(aq) , is the maximum possible concentration of Pb2+(aq) in the solution greater than, less th

fredd [130]

Answer:

$\mathbf{s =\sqrt [3]{\dfrac{K_{sp}}{4}}}$

Less than the concentration of Pb2+(aq) in the solution in part ( a )

Explanation:

From the question:

We assume that s to be the solubility of PbI₂.

The equation of the reaction is given as :

PbI₂(s) ⇌ Pb²⁺(aq) + 2I⁻(aq); Ksp = 7 × 10⁻⁹

[Pb²⁺] = s

Then [I⁻] = 2s

$K_{sp} =\text{[Pb$^{2+}$][I$^{-}$]}^{2} = s\times (2s)^{2} = 4s^{3}\\s^{3} = \dfrac{K_{sp}}{4}\\\\s =\mathbf{ \sqrt [3]{\dfrac{K_{sp}}{4}}}\\\\\text{The mathematical expressionthat can be used to determine the value of }\mathbf{s =\sqrt [3]{\dfrac{K_{sp}}{4}}}$

The Concentration of Pb²⁺ in water is calculated as :

$\mathbf{s =\sqrt [3]{\dfrac{K_{sp}}{4}}}$

$\mathbf{s =\sqrt [3]{\dfrac{7*10^{-9}}{4}}}$

$\mathbf{s} =\sqrt[3]{1.75*10^{-9}}$

$\mathbf{s} =\mathbf{1.21*10^{-3} \ mol/L }$

The Concentration of Pb²⁺ in 1.0 mol·L⁻¹ NaI

$\mathbf{PbCl{_2}} \leftrightharpoons \ \ \ \ \ \ \ \mathbf{Pb^{2+}} \ \ \ \ \ + \ \ \ \ \ \ \ \mathbf{2 I^-}$

$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \mathbf0} \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \mathbf{1.0}$

$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \mathbf{+x} \ \ \ \ \ \ \ \ \ \ \ \ \mathbf{+2x}$

$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \mathbf{+x} \ \ \ \ \ \ \ \ \ \ \ \ \mathbf{1.0+2x}$

The equilibrium constant:

$K_{sp} =[Pb^{2+}}][I^-]^2 \\ \\ K_{sp} = s*(1.0*2s)^2 =7*1.0^{-9} \\ \\ s = 7*10^{-9} \ \ m/L$

It is now clear that maximum possible concentration of Pb²⁺ in the solution is less than that in the solution in part (A). This happens due to the common ion effect. The added iodide ion forces the position of equilibrium to shift to the left, reducing the concentration of Pb²⁺.

3 0

2 years ago