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3 years ago

What distinguishes a substance from a mixture?

1 answer:

4 0

A mixture consists of numerous substances, whereas a substance does not consist of mixtures, but rather of compounds. Mixtures can be separated physically, while substances cannot.

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What are the spectator ions in the equation below? Select all that apply.

Licemer1 [7]

Answer:

H+ and NO3- ions

Explanation:

The Pb²+ ions react with the SO4²‐ ions to form a solid precipitate, i.e. they bond together and undergo a phase change;

On the contrary, the H+ and NO3- ions are aqueous ions before the reaction and the same after the reaction, i.e. they don't change;

Hence, the H+ and NO3- ions are spectator ions

The way to do this type of question is to consider what changes and what doesn't, look at phase changes and oxidation state changes

7 0

2 years ago

HELP NOW!!

Bess [88]

Alkaline Earth Metals are the elements located in the second period from the left of the periodic table. These elements lose two electrons to form the stable octet when forming an ionic bond, resulting in a net charge of +2. Because they’re trying to get rid of those electrons to get to the stable octet, it’s easy to remove them - this means that the ionization energy of these elements is relatively low. Finally, since they’re looking to get rid of electrons, they certainly aren’t trying to gain any, meaning that their electronegativity is relatively low.

The correct answers are A and D.

3 0

2 years ago

Read 2 more answers

Calculate the relative density of carbon monoxide and carbon dioxide with respect to air.

JulsSmile [24]

Density is proportional to molar mass, assuming pressure and temperature remain constant. Therefore, since CO has a molar mass of 28 and CO2 has a molar mass of 44:
The relative density of CO vs air is 28/29 = 0.9655.
The relative density of CO2 vs air is 44/29 = 1.517.

3 0

3 years ago

Does the fossil record include every species that every lived? Why or why not?

fgiga [73]

No, some species didn’t have bones and things of the such that could become fossilized.

3 0

3 years ago

You placed a sample of a hydrate of calcium chloride (CaCl2) in a weighed test tube, and weighed the filled test tube.

ziro4ka [17]

Answer:

1. 5g

2. 2.3g

3. 2.7g

4. 0.02mol

5. 0.13mol

6. 7moles

Explanation:

From the question, the following were obtained:

Mass of empty tube = 13.5g

Mass of empty tube + hydrated salt = 18.5g

Mass of tube + anhydrous salt = 16.2g

1. Mass of empty tube = 13.5g

Mass of empty tube + hydrated salt = 18.5g

Mass of hydrated salt = 18.5 — Mass of empty tube

Mass of hydrated salt = 18.5 — 13.5 = 5g

2. Let us calculate the mass of the anhydrous salt.

Mass of tube + anhydrous salt = 16.2g

Mass of empty tube = 13.5g

Mass of anhydrous salt = 16.2 — Mass of empty tube = 16.2 — 13.5

Mass of anhydrous salt = 2.7g

Now we can calculate the mass of the water evolved as follows:

Mass of water = Mass of hydrated salt — Mass of anhydrous

Mass of water = 5 — 2.7 = 2.3g

3. Mass of empty tube = 13.5g

Mass of anhydrous salt = 16.2 — Mass of empty tube = 16.2 — 13.5

Mass of anhydrous salt = 2.7g

4. MM of CaCl2 = 40 +(2x35.5) = 40 + 71 = 111g

Mass of CaCl2 = 2.7g

Number of mole = Mass /Molar Mass

Number of mole of CaCl2 = 2.7/111 = 0.02mol

5. MM of H2O = (2x1) +16 = 2 + 16 = 18g/mol

Mass of H2O = 2.3g

Number of mole = Mass /Molar Mass

Number of mole of H20 = 2.3/18 = 0.13mol

6. To get the mole of water in the molecular formula, we will find the ratio of the number of mole of anhydrous salt to water as shown below:

Mole anhydrous : mole of water ie

0.02 : 0.13 = 1 : 7

Therefore, the mole of water in the formula is 7 ie

CaCl2.7H20

3 0

3 years ago