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3 years ago

Will the ph of a solution of nh4cn be >7, <7, or =7?

1 answer:

7 0

PH of a solution will be <span>higher than 7
</span>
Ammonium cyanide is a salt formed by hydrogen cyanide and ammonia. Ammonia is a weak base and hydrogen cyanide is a weak acid.
NH₄CN + H₂O ⇒ NH₃ + HCN

NH₄⁺ + H₂O -----> H₃O⁺ + NH₃

CN⁻ + H₂O -----> HCN + OH⁻

Although both compounds are weak electrolytes, NH₃ is somewhat stronger base than HCN is a strong acid, so the solution reacts alkaline. We can prove this using Ka and Kb values:

Ka(HCN) = 4.9 x × 10⁻¹⁰

Kb(NH₃) = 1.8 × 10⁻⁵<span>
Kw= </span>1.0 × 10⁻¹⁴

Let's first calculate Ka for NH₄⁺:
Ka(NH₄⁺) x Kb(NH₃<span>) = pKw

</span>Ka(NH₄⁺) = Kw/Kb(NH₃) = 5.6 x 10⁻¹⁰

Then, Kb for CN⁻:

Kb(CN⁻) x Ka(HCN) = pKw

Kb(CN⁻) = Kw/Ka(HCN) = 2 x 10⁻⁵

From this, we can see that the acid constant NH4⁺ is much lower than the base constant of CN⁻, which will say that the solution of NH₄CN will react slightly alkaline because of the higher presence of hydroxyl ions in solution.

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During a lab exam a student looked through the microscope and identified the following cell parts: circular DNA, ribosomes, cell

notsponge [240]

Answer:

The correct answer to this question is a prokaryotic cell.

Explanation:

Prokaryotes have circular DNA and a cell wall, whereas eukaryotes have their DNA packaged into chromosomes and may not have a cell wall (as is the case in animal cells).

Hope this helps!

5 0

2 years ago

Endler's Guppies Experiment on Natural Selection

Morgarella [4.7K]

In conclusion, an experiment about Natural Selection includes mechanisms, explanation, estimation of the frequency of the trait and comparisons.

<h3>What is the scientific method?</h3>

The scientific method is a series of step used to validate evidence and thus formulate theories.

Darwin used the scientific method to draw conclusions about the main mechanism of evolution, i.e., natural selection.

The scientific method involves making a question, providing an explanation of the hypothesis, making observations/experiments (which include experimental and control groups), and drawing conclusions.

The empirical data serve to test a hypothesis (either confirm or reject it) by contrasting its results with predictive outcomes.

The strength of the conclusions can be enhanced by using supporting evidence from other research fields (in this case, for example, the fossil record).

In conclusion, an experiment on Natural Selection includes mechanisms (question), explanation (hypothesis), estimation of the frequency of the trait in the population (prediction) and comparisons (control group).

Learn more about the scientific method here:

brainly.com/question/17216882

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7 0

2 years ago

HClO4 acid solution has a concentration of 5 Molarity. Calculate the concentration of this solution in

Nutka1998 [239]

Answer:

1. Percentage by weight = 0.5023 = 50.23 %

2. molar fraction =0.153

Explanation:

We know that

Molar mass of HClO4 = 100.46 g/mol

So the mass of 5 Moles= 5 x 100.46

Mass (m)= 5 x 100.46 = 502.3 g

Lets assume that aqueous solution of HClO4 and the density of solution is equal to density of water.

Given that concentration HClO4 is 5 M it means that it have 5 moles of HClO4 in 1000 ml.

We know that

Mass = density x volume

Mass of 1000 ml solution = 1 x 1000 =1000 ( density = 1 gm/ml)

m'=1000 g

Percentage by weight = 502.3 /1000

Percentage by weight = 0.5023 = 50.23 %

We know that

molar mass of water = 18 g/mol

mass of water in 1000 ml = 1000 - 502.3 g=497.9 g

So moles of water = 497.7 /18 mole

moles of water = 27.65 moles

So molar fraction = 5/(5+27.65)

molar fraction =0.153

6 0

2 years ago

In Environment A, trees are growing back and some of the larger animals are returning to a logged forest. In Environment B, lich

laiz [17]

Answer:

Environment A is not undergoing succession, and Environment B is.

Explanation:

Ecological succession is a gradual process in which ecosystems significantly change over time. Ecological succession is a term used by scientists to describe the change in the structure of a community of different species, or ecosystem. This concept of ecological succession stems from a desire to understand the patterns of change in large and complex ecosystems like forests and how they can exist in places known to be recently formed, such as volcanic islands.

In environment A, the ecosystem is not really changing, organisms are merely returning to their natural habitat. It does not represent any change in the ecosystem.

In environment B, the original ecosystem has become grossly modified, first by the appearance of lichen and mosses and subsequently by grasses shrubs and animals. These sequence of events correlate well with the idea of ecological succession presented in the opening paragraph hence environment B is undergoing ecological succession.

4 0

3 years ago

Read 2 more answers

What are 2 mixtures and explain your answer

liq [111]

Water and orange juice
Or orange juice and sodium chloride

3 0

2 years ago