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2 years ago

13. Which statement best describes an element? *

Chemistry

1 answer:

Natasha2012 [34]2 years ago

4 0

Explanation:

Distinguish chemical substances from mixtures

Key Points

Matter can be broken down into two categories: pure substances and mixtures. Pure substances are further broken down into elements and compounds. Mixtures are physically combined structures that can be separated into their original components.

A chemical substance is composed of one type of atom or molecule.

A mixture is composed of different types of atoms or molecules that are not chemically bonded.

A heterogeneous mixture is a mixture of two or more chemical substances where the various components can be visually distinguished.

A homogeneous mixture is a type of mixture in which the composition is uniform and every part of the solution has the same properties.

Various separation techniques exist in order to separate matter, including include distillation, filtration, evaporation and chromatography. Matter can be in the same phase or in two different phases for this separation to take place.

Terms

substanceA form of matter that has constant chemical composition and characteristic properties. It is composed of one type of atom or molecule.

elementA chemical substance that is made up of a particular kind of atom and cannot be broken down or transformed by a chemical reaction.

mixtureSomething that consists of diverse, non-bonded elements or molecules.

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You titrate 25.00 mL of the lemon-lime Kool-Aid (with KI, HCl, and starch) with 0.001000 M KIO3(aq) solution. The titration requ

Svetradugi [14.3K]

Answer:

1.0190 x 10⁻⁵ mol

Explanation:

We know the titration required 10.19 mL of 0.001000 M KIO₃, from this information we can calculate the number of moles KIO₃ reacted and from there the number of moles of ascorbic acid since it is a monoprotic acid ( 1 equivalent of ascorbic acid to one equivalent KIO₃).

Molarity = mol/V

V KIO₃ = 10.19 mL = 10.19 mL x 1 L/1000 mL = 0.01019 L

⇒ mol KIO₃ = V x M = 0.01019 L x 0.0010 mol / L = 1.0190 x 10⁻⁵ mol KIO₃

# mol ascorbic acid = # mol KIO₃ = 1.0190 x 10⁻⁵ mol

8 0

2 years ago

If 450.0 mL of a 0.500 M solution is mixed with 200.0 mL of water, what is the molarity of the new

Oksana_A [137]

Answer:

Answer: A) .346 M

Explanation:

Given:

- 450 mL

- .5 M soln

-200 mL water

1) Convert mL to L

450 mL = .45 L

200 mL = .2 L

2) Find mols in solution

.5 M = x/.45 L

x = .225 mol

3) Find total volume of solution

.45 L + .2 L =.65 L

4) Find new molarity

molarity (M) = mols solute/ L solution

y = .225 mol (from step 2)/ .65 L (from step 3)

y = .346 M

Answer: A) .346 M

7 0

2 years ago

What is the molar mass of an unknown gas with a density of 2.00 g/L at 1.00 atm and 25.0 °C?

soldier1979 [14.2K]

Answer:

Explanation:Explanation:

Your starting point here will be the ideal gas law equation

∣

¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

∣

−−−−−−−−−−−−−−−

, where

- the pressure of the gas

- the volume it occupies

- the number of moles of gas

- the universal gas constant, usually given as

0.0821

atm

⋅

mol

⋅

- the absolute temperature of the gas

Now, you will have to manipulate this equation in order to find a relationship between the density of the gas,

, under those conditions for pressure and temperature, and its molar mass,

You know that the molar mass of a substance tells you the mass of exactly one mole of that substance. This means that for a given mass

of this gas, you can express its molar mass as the ratio between

and

, the number of moles it contains

∣

¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

∣

−−−−−−−−−−−−−

(

)

Similarly, the density of the substance tells you the mass of exactly one unit of volume of that substance.

This means that for the mass

of this gas, you can express its density as the ratio between

and the volume it occupies

∣

¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

∣

−−−−−−−−−−−

(

)

Plug equation

(

)

into the ideal gas law equation to get

⋅

Rearrange to get

⋅

Finally, use equation

(

)

to write

⋅

Convert the temperature of the gas from degrees Celsius to Kelvin then plug in your values to find

1.02

⋅

0.0821

atm

⋅

mol

⋅

(

273.15

)

0.990

atm

∣

¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

26.3 g mol

−

∣

−−−−−−−−−−−−−−−−

I'll leave the answer rounded to three

7 0

3 years ago

John is carefully pouring a chemical into a beaker when the beaker slips and breaks

Kryger [21]

Following laboratory safety protocols such as wearing personal protective equipment will protect John when the accident occurred.

<h3>What are laboratory safety protocols?</h3>

Laboratory safety protocols are the protocols put in place to ensure safety in the laboratory.

Laboratory safety protocols include the following:

always wear personal protective equipment in the laboratory
do not play in the laboratory
do not eat in the laboratory

Following laboratory safety protocols will help protect us from accidents which occur in the laboratory.

What happened when john was carefully pouring a chemical into a beaker when the beaker slips and breaks is an example of laboratory accident.

Wearing personal protective equipment will protect John.

In conclusion, following laboratory safety protocols will protect us when accidents occur in the laboratory.

Learn more about laboratory safety protocols at: brainly.com/question/17994387

#SPJ1

Note that the complete question is given as follows:

John is carefully pouring a chemical into a beaker when the beaker slips and breaks. How would laboratory safety protocols help John?

5 0

1 year ago

victus00 [196]

Answer:

This isotope has 59 electrons giving it a charge of -2.

Explanation:

To find this we have to understand isotope relates to the mass of the nucleus. This isotope has 59 electrons to counter the protons and give it a negative charge.

6 0

2 years ago