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3 years ago

Which step accurately describes how to measure the final burette volume?

2 answers:

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To accurately measure the final volume of a solution in a burette, it is important that you read of the measurement in the lower meniscus like for water and for substances like mercury you read it on the upper meniscus. This is the standard way of reading volumes in laboratory apparatus. Also, it should be that the apparatus standing vertically in a plain surface.

LekaFEV [45]3 years ago

3 0

Answer:

The precision to measure a volume in a burette will depend on the shape of the meniscus that forms the liquid. In the case of a concave meniscus, its reading will be made at the lowest height of the liquid surface. This point should touch the upper edge in the division of the burette scale. In the case of a convex meniscus, its reading will be made at the highest height of the liquid surface. This point should touch the bottom edge in the burette scale division.

Explanation:

The accuracy when reading the correct volume in a burette depends on the type of meniscus. If the molecules of a liquid have a greater attraction to the glass wall, the meniscus will have a concave shape, for example, aqueous solutions. A requirement to measure exactly is the adjustment of the meniscus. As stated before, if the meniscus shape is concave, the volume will be read at the lowest height of the liquid surface. If the meniscus is convex, the volume will be taken at the highest height of the liquid surface. Convex menisci are formed by substances such as mercury.

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Which of the following statements is true?

vlabodo [156]

In an unsaturated solution, the amount of solute is less than required in the solution. So, it can dissolve more solute.

Solid state is more dense than the liquid state as the molecules are closely packed in a solid.

Density is temperature dependent as with increase in temperature volume increases. So, the density decreases.

Like dissolves like. A polar solute will dissolve in a polar solvent.

So, the correct statement among the given options is B.For most substances, the solid state is more dense than the liquid state.

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4 years ago

Read 2 more answers

"Two major varieties of igneous rock are _______ and ________. What is the difference between these two types of igneous rock?"

grandymaker [24]

Answer:

Intrusive and Extrusive igneous rocks.

Explanation:

Igneous rocks are defined as those rocks that are formed when magma undergoes the process of crystallization and solidification at or below the earth's surface. For example, Granite, Rhyolite, Gabbro and Diorite.

The igneous rocks are of two different types, namely-

Intrusive igneous rocks- This type of igneous rocks are formed when the magma crystallizes below or within the earth's crust. For example, Granite.

Extrusive igneous rocks- This type of igneous rocks are formed when the magma crystallizes and solidifies at the surface of the earth. For example, Basalt.

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3 years ago

If my dog weighs 31.8 kilograms, how much would she weigh in ounces? Round your to the 1st decimal place.

lidiya [134]

Your dog would weigh 1121.7 ounces

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3 years ago

A student prepares a aqueous solution of trimethylacetic acid . Calculate the fraction of trimethylacetic acid that is in the di

irinina [24]

The question is incomplete, here is the complete question:

A student prepares a 0.21 mM aqueous solution of trimethylacetic acid. Calculate the fraction of trimethylacetic acid that is in the dissociated form in his solution. Express your answer as a percentage. You will probably find some useful data in the ALEKS Data resource. Round your answer to 3 significant digits.

Answer: The percent of dissociation of trimethylacetic acid is 19.5 %

Explanation:

We are given:

Concentration of trimethylacetic acid = 0.21 mM = 0.00021 M (Conversion factor: 1 mole = 1000 millimoles )

The chemical equation for the dissociation of trimethylacetic acid follows:

$C_4H_9COOH\rightleftharpoons C_4H_9COO^-+H^+$

Initial: 0.00021

At eqllm: 0.00021-x x x

The expression of $K_a$ for above equation follows:

$K_a=\frac{[C_4H_9COO^-][H^+]}{[C_4H_9COOH]}$

We know that:

$K_a\text{ for }C_4H_9COOH=1\times 10^{-5}$

Putting values in above expression, we get:

$1\times 10^{-5}=\frac{x\times x}{(0.00021-x))}\\\\x=0.000041,-0.000051$

Neglecting the negative value of 'x' because concentration cannot be negative.

To calculate the fraction of dissociation, we use the equation:

$\text{Percent of dissociation}=\frac{[H^+]}{[C_4H_9COOH]}\times 100$

Putting values in above equation, we get:

$\text{Percent of dissociation}=\frac{0.000041}{0.00021}\times 100\\\\\text{Percent of dissociation of trimethylacetic acid}=19.5%$

Hence, the percent of dissociation of trimethylacetic acid is 19.5 %

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3 years ago

What answer names a producer in an ecosystem

Temka [501]

Answer:

Fir tree

Explanation:

Producers, Consumers, and Decomposers in the Forest Community. Producers are any kind of green plant. Green plants make their food by taking sunlight and using the energy to make sugar. The plant uses this sugar, also called glucose to make many things, such as wood, leaves, roots, and bark. Rabbit, Fungus, and raccoon are all decomposers!

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4 years ago