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3 years ago

Compare and contrast the fine and coarse adjustment knobs on a microscope

Chemistry

1 answer:

IceJOKER [234]3 years ago

8 0

The fine adjustment knob focuses an image. The coarse adjustment knod moves the slide up or down.

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A saturated solution of Pb(IO3)2 in pure water has a lead ion concentration of 5.0 x 10-5 Molar. What is the Ksp value of Pb(IO3

Orlov [11]

Answer:

Option (E) is correct

Explanation:

Solubility equilibrium of $Pb(IO_{3})_{2}$ is given as follows-

$Pb(IO_{3})_{2}\rightleftharpoons Pb^{2+}+2IO_{3}^{-}$

Hence, if solubility of $Pb(IO_{3})_{2}$ is S (M) then-

$[Pb^{2+}]=S(M)$ and $[IO_{3}^{-}]=2S(M)$

Where species under third bracket represent equilibrium concentrations

So, solubility product of $Pb(IO_{3})_{2}$ , $K_{sp}=[Pb^{2+}][IO_{3}^{-}]^{2}$

Here, $[Pb^{2+}]=S(M)=5.0\times 10^{-5}M$

So, $[IO_{3}^{-}]=2S(M)=(2\times 5.0\times 10^{-5})M=1.0\times 10^{-4}M$

So, $K_{sp}=(5.0\times 10^{-5})\times (1.0\times 10^{-4})^{2}=5.0\times 10^{-13}$

Hence option (E) is correct

7 0

3 years ago

What is the difference between food web and food chain and what do they have in common?

abruzzese [7]

A food web is a system of interlocking and interdependent food chains.

A food chain is a hierarchical series of organisms each dependent on the next as a source of food.

Basically, the difference of the two is that a food web contains multiple different species in the same level that eat the animal below it's status. A food chain is one after the other.

7 0

3 years ago

What mass of powdered drink mix is needed to make a 0.5 M solution of 100 mL?

Maru [420]

Answer:

There is 17,114825 g of powdered drink mix needed

Explanation:

Step 1 : Calculate moles

As given, the concentration of the drink is 0.5 M, this means 0.5 mol / L

Since the volume is 100mL, we have to convert the concentration,

⇒0.5 / 1 = x /0.1 ⇒ 0.5* 0.1 = x = 0.05 M

This means there is 0.05 mol per 100mL

Step 2 : calculate mass of the powdered drink

here we use the formula n (mole) = m(mass) / M (Molar mass)

⇒ since powdered drink mix is usually made of sucrose (C12H22O11) and has a molar mass of 342.2965 g/mol.

0.05 mol = mass / 342.2965 g/mol

To find the mass, we isolate it ⇒0.05 mol * 342.2965 g/mol = 17,114825g

There is 17,114825 g of powdered drink mix needed

3 0

3 years ago

Read 2 more answers

example best shows that the chemistry of water is helpful to plants? Water’s polarity produces a high density, which allows wate

Gennadij [26K]

The right answer for the question that is being asked and shown above is that: "Water’s polarity produces a high density, which allows water to move to the leaves." Example best shows that the chemistry of water is helpful to plants is that Water’s polarity produces a high density, which allows water to move to the leaves.

8 0

3 years ago

Read 2 more answers

As with other ionic compounds, potassium bromate, KBrO3, dissociates into ions when it dissolves in water. If 13.8 g of KBrO3 is

chubhunter [2.5K]

Answer:

ΔH of dissociation is 38,0 kJ/mol

Explanation:

The dissociation reaction of KBrO₃ is:

KBrO₃ → K⁺ + BrO₃⁻ 

This dissolution consume heat that is evidenced with the decrease in water temperature.

The heat consumed is:

q = CΔTm

Where C is specific heat of water (4,186 J/mol°C)

ΔT is the temperature changing (18,0°C - 13,0°C = 5,0°C)

And m is mass of water (150,0 mL ≈ 150,0 g)

Replacing, heat consumed is:

q = 3139,5 J ≡ 3,14 kJ

13,8 g of KBrO₃ are:

13,8 g×(1mol/167g) = 0,0826 moles

Thus, ΔH of dissociation is:

3,14kJ / 0,0826mol = 38,0 kJ/mol

I hope it helps!

3 0

3 years ago