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3 years ago

Which of the following are considered pure substances?

Chemistry

2 answers:

Tanzania [10]3 years ago

8 0

Element. Everything is else is a mixture, therefore not pure.

Ganezh [65]3 years ago

3 0

Answer: A. Element and B. Compound

Explanation:

Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Copper $Cu$

Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water $H_2O$

Heterogeneous mixture : It is a mixture that has non-uniform composition throughout the solution and the particle size or shapes are also different.There is a physical boundary between the dispersed phase and dispersion medium.

Homogeneous mixture: It is a mixture that has uniform composition throughout the solution and the particle size or shapes are not different.There is no physical boundary between the dispersed phase and dispersion medium.

Thus element and compound are pure substances.

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determine the average volume from the following volume reading: 3.00ml, 2.0ml, 2.987 x 10^-3 l, and 3.4856 ml

lesya [120]

Answer:

The average of given values is 2.1221 ml

Explanation:

Given data:

Given measurements = 3.00 ml , 2.0 ml, 2.987 × 10⁻³ml , 3.4856 ml

Average value of given measurements = ?

Solution:

Formula:

Average value = sum of all measurement / total number of measurements

2.987 × 10⁻³ml = 0.002987 ml

Now we will put the values.

Average value = 3.00 ml + 2.0 ml + 0.002987 ml+ 3.4856 ml / 4

Average value = 8.488587 ml / 4

Average value = 2.1221 ml

The average of given values is 2.1221 ml

8 0

3 years ago

A mixture of 0.10 mol of NO, 0.050 mol of H2, and 0.10 mol of H2O is placed in a 1.0-L vessel at 300 K. The following equilibriu

tatyana61 [14]

Answer:

[H2] = 0.012 M

[N2] = 0.019 M

[H2O] = 0.057 M

Explanation:

The strategy here is to account for the species at equilibrium given that the concentration of [NO]=0.062M at equilibrium is known and the quantities initially present and its stoichiometry.

2NO(g) + 2H2(g) ⇒ N2(g) + 2H2O(g)

i mol 0.10 0.050 0.10

c mol -0.038 -0.038 +0019 +0.038

e mol 0.062 0.012 00.019 0.057

Since the volume of the vessel is 1.0 L, the concentrations in molarity are:

[NO] = 0.062 M

[H2] = 0.012 M

[N2] = 0.019 M

[H2O] = 0.057 M

5 0

2 years ago

A different student is given a 10.0g sample labeled CaBr2 that may contain an inert (nonreacting) impurity. Identify a quantity

grandymaker [24]

Answer:

Mass of Ca in sample, Mass of Br in sample, Number of moles of Ca in sample, Number of moles of Br in sample, Mass or moles of element other than Ca or Br in sample

Explanation:

The AP Classroom will not count your answer to this question as correct unless it includes at least one of the answers listed above. If you say that theanswer to this question is density, it will be marked as incorrect, I found that out the hard way when I used the answers that brainly gave me.

Good luck,

I applaud you for using the sources avalible to you, which is /definetly not/ cheeting.

8 0

2 years ago

What quantity can be calculated for a solid compound, given only the formula of the compound and the periodic table of elements

gavmur [86]

When you have both of these ( The periodic table of elements and the formula of your compound) you are able to calculate the R.M.M ( Relative atomic mass) of that compound.
For example the formula of a NaCl ( Table salt ) has the elemnt Na and Cl.
We look at the atomic mass of both of these compounds
Na - 23
Cl - 35.5
R.M.M = 23 +35.5 = 58.5
Hope this helps :).

6 0

2 years ago

Chemical properties of sodium

Svetlanka [38]

Answer:

Density 0.97 g.cm -3 at 20 °C

Melting point 97.5 °C

Boiling point 883 °C

oxidation states +1, −1 (rare)

Explanation:

Have a nice day

5 0

2 years ago