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3 years ago

Which of the following observations would indicate that a material is a pure substance

Chemistry

2 answers:

Lena [83]3 years ago

3 0

What is the following

yaroslaw [1]3 years ago

3 0

It does not dissolve in water.

It changes color after heating.

It cannot be physically broken down into different types of atoms.

It can be physically broken down into different types of molecules.

^the options

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What does bacteria cell and plant cell have in common

Natasha_Volkova [10]

Answer:

They both have a cell wall

Explanation:

7 0

3 years ago

is a polyprotic acid. Write balanced chemical equations for the sequence of reactions that carbonic acid can undergo when it's d

Burka [1]

Answer:

H₂CO₃ H₂O ⇄ HCO₃⁻ + H₃O⁺ Ka1

HCO₃⁻ + H₂O ⇄ CO₃⁻² + H₃O⁺ Ka2

CO₃⁻² + H₂O ⇄ HCO₃⁻ + OH⁻ Kb1

HCO₃⁻ + H₂O ⇄ H₂CO₃ + OH⁻ Kb2

Explanation:

Formula for carbonic acid is: H₂CO₃

It is a dyprotic acid, because it can release two protons. We can also mention that is a weak one. The equilibrums are:

H₂CO₃ H₂O ⇄ HCO₃⁻ + H₃O⁺ Ka1

HCO₃⁻ + H₂O ⇄ CO₃⁻² + H₃O⁺ Ka2

When the conjugate strong bases, carbonate and bicarbonate take a proton from water, the reactions are:

CO₃⁻² + H₂O ⇄ HCO₃⁻ + OH⁻ Kb1

HCO₃⁻ + H₂O ⇄ H₂CO₃ + OH⁻ Kb2

Notice, that bicarbonate anion can release or take a proton to/from water. This is called amphoteric,

6 0

3 years ago

What happens when water is added to a sand-salt mixture

s2008m [1.1K]

The salt dissolves in the water and the sand will gather at the bottom.

8 0

4 years ago

Read 2 more answers

From your observations of the simulation, which strategy was most effective for quickly and efficiently producing ammonia? Why d

Bogdan [553]

Answer:

The electrochemical synthesis of ammonia from nitrogen under mild conditions using renewable electricity is an attractive alternative to the energy-intensive Haber–Bosch process, which dominates industrial ammonia production.

Explanation:

However, there are considerable scientific and technical challenges facing the electrochemical alternative, and most experimental studies reported so far have achieved only low selectivities and conversions. The amount of ammonia produced is usually so small that it cannot be firmly attributed to electrochemical nitrogen fixation rather than contamination from ammonia that is either present in air, human breath or ion-conducting membranes, or generated from labile nitrogen-containing compounds (for example, nitrates, amines, nitrites and nitrogen oxides) that are typically present in the nitrogen gas stream, in the atmosphere or even in the catalyst itself. Although these sources of experimental artefacts are beginning to be recognized and managed, concerted efforts to develop effective electrochemical nitrogen reduction processes would benefit from benchmarking protocols for the reaction and from a standardized set of control experiments designed to identify and then eliminate or quantify the sources of contamination.

8 0

4 years ago

What volume, in milliliters, of water is needed to make an 8.40 M solution of HCl acid using 180. grams of HCI ?

8_murik_8 [283]

Answer:

0 587 mL

Explanation:

First we convert 180 grams of HCl into moles, using its molar mass:

180 g ÷ 36.46 g/mol = 4.94 mol HCl

Now we can use the number of moles and the given concentration to calculate the required volume, applying the definition of molarity:

Molarity = moles / liters

Liters = Moles / molarity

4.94 mol / 8.40 M = 0.588 L

Finally we convert liters into milliliters:

0.588 L * 1000 = 588 mL

The closest answer is option C, 587 mL.

7 0

4 years ago