All categories

3 years ago

Contrast mixtures with pure substances

Chemistry

1 answer:

dimaraw [331]3 years ago

7 0

Mixtures

consist of two or more substances
have a variable composition
can be separated into their components by physical means

Pure substances

consist of a single element or compound
have a definite and constant composition
cannot be separated into their components by physical means

You might be interested in

Which reaction is a decomposition reaction? A. 2KClO3 → 2KCl + 3O2 B. 4Na + O2 → 2Na2O C. ZnS + 3O2 → 2ZnO + 2SO2 D. 2NaBr + CaF

Vedmedyk [2.9K]

Answer:

Option A. 2KClO₃ → 2KCl + 3O₂

Explanation:

There are five basic general types of chemical reactions:

Decomposition reactions

Synthesis or combination reaction

Single replacement reactions

Double replacement reactions

Combustion reactions

The given reactions are:

2KClO₃ → 2KCl + 3O₂

Which is, indeed, a decomposition reaction because the reactant, KClO₃, is a single substance that undergoes a reaction in which it yields two new substances, known as products: KCl and O₂.

4Na + O₂ → 2Na₂O is a synthesis or combination reaction because two reactants, Na and O₂, combine for the formation of one single new product, Na₂O.

ZnS + 3 O₂ → 2ZnO + 2SO₂ is a single replacement reaction because oxygen is replacing Zn and S in ZnS to form ZnO and plus SO₂.

2NaBr + CaF₂ → 2NaF + CaBr₂ is a double replacement reaction because two ions (Br⁻ from NaBr and F⁻ from CaF₂) are exchanging places with other two ions (Na⁺ from NaBr and Ca²⁺ from CaF₂) two form two new ionic compounds (NaF and CaBr₂).

4 0

2 years ago

The Element rhenium has two naturally occurring isotopes, 185 Re and 187 Re, with an average atomic mass of 186.207 amu. Rhenium

BigorU [14]

To calculate the average mass of the element, we take the summation of the product of the isotope and the percent abundance. In this case, the equation becomes 186.207=187*0.626+185*x where x is the percent abundance of 185. The answer is 0.374 or 37.4%. This can also be obtained by 100%-62.6%= 37.4%.

8 0

2 years ago

Why are there so many capillaries in the lungs?

AysviL [449]

There's a lot of capillaries in the lungs because the blood needs to be transferred and the capillaries are the smallest vessels that can do this.

6 0

3 years ago

The distance between the centers of the two oxygen atoms in an oxygen molecule is 1.21 x 10-8 cm. What is this distance in inche

Sergio [31]

Answer:

$d=4.75\times 10^{-9}\ \text{inches}$

Explanation:

Given that,

The distance between the centers of the two oxygen atoms in an oxygen molecule is $1.21\times 10^{-8}\ cm$ .

We need to convert this distance in inches.

We know that,

1 cm = 0.393 inches

We can solve it as follows :

$1.21\times 10^{-8}\ cm=0.393\times 1.21\times 10^{-8}\\\\=4.75\times 10^{-9}\ \text{inches}$

So, the distance between the centers of the two oxygen atoms is $4.75\times 10^{-9}\ \text{inches}$ .

5 0

2 years ago

Question 11 point)

MrMuchimi

Answer:

The correct option is C) the moon takes the same time to rotate and revolve.

Explanation:

Scientific experiments have concluded that it takes approximately 23 days for the moon to rotate and also it takes the same duration for the moon to revolve around the Earth. Due to this consistency, the moon appears to be still.

Such synchronization results in the same face of the moon to be directed towards the Earth. Hence, the same craters of the moon will be observed by the scientist every day.

Other options, like option D, is not correct because there will be craters on the other side of the moon too. But as we see the same side of the moon, hence we cannot see the craters present on the other side of the moon.

5 0

3 years ago