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2 years ago

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An isotope of lead can be represented by the following symbol ²⁰⁷ 82 PB. From this symbol, it can be deduced that one atom of th

e isotope has: A) 82 neutrons B) 82 protons C) 125 protons D) 207 protons

1 answer:

9966 [12]2 years ago

6 0

Answer:

B) 82 protons

Explanation:

The number of protons for an element never change. 82 Is the atomic number for Pb which is how many protons it has. An isotope means it has more neutrons.

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never [62]

Energy released from cell respiration is know as ATP

4 0

2 years ago

Suppose you have just added 100 ml of a solution containing 0.5 mol of acetic acid per liter to 400 ml of 0.5 m naoh. what is th

Tpy6a [65]

$pH = 13.5$

Explanation:

Sodium hydroxide completely ionizes in water to produce sodium ions and hydroxide ions. Hydroxide ions are in excess and neutralize all acetic acid added by the following ionic equation:

$\text{HAc} + \text{OH}^{-} \to \text{Ac}^{-} + \text{H}_2\text{O}$

The mixture would contain

$0.4 \times 0.5 - 0.1 \times 0.5 = 0.15 \; \text{mol}$ of $\text{OH}^{-}$ and
$0.1 \times 0.5 = 0.05 \; \text{mol}$ of $\text{Ac}^{-}$

if $\text{Ac}^{-}$ undergoes no hydrolysis; the solution is of volume $0.1 + 0.4 = 0.5 \; \text{L}$ after the mixing. The two species would thus be of concentration $0.30 \; \text{mol} \cdot \text{L}^{-1}$ and $0.10 \; \text{mol} \cdot \text{L}^{-1}$ , respectively.

Construct a RICE table for the hydrolysis of $\text{Ac}^{-}$ under a basic aqueous environment (with a negligible hydronium concentration.)

$\begin{array}{cccccccc} \text{R} & \text{Ac}^{-}(aq) &+ & \text{H}_2\text{O}(aq) & \leftrightharpoons & \text{HAc}(aq) & + & \text{OH}^{-} (aq)\\ \text{I} & 0.10 \; \text{M} & & & & & &0.30 \; \text{M}\\ \text{C} & -x \; \text{M}& & & & +x \; \text{M}& & +x \; \text{M} \\ \text{E} & (0.10 - x) \; \text{M} & & & & x \; \text{M} & & (0.30 +x) \; \text{M} \end{array}$

The question supplied the <em>acid</em> dissociation constant $pK_a$ for acetic acid $\text{HAc}$ ; however, calculating the hydrolysis equilibrium taking place in this basic mixture requires the <em>base</em> dissociation constant $pK_b$ for its conjugate base, $\text{Ac}^{-}$ . The following relationship relates the two quantities:

$pK_{b} (\text{Ac}^{-}) = pK_{w} - pK_{a}( \text{HAc})$

... where the water self-ionization constant $pK_w \approx 14$ under standard conditions. Thus $pK_{b} (\text{Ac}^{-}) = 14 - 4.7 = 9.3$ . By the definition of $pK_b$ :

$[\text{HAc} (aq)] \cdot [\text{OH}^{-} (aq)] / [\text{Ac}^{-} (aq) ] = K_b = 10^{-pK_{b}}$

$x \cdot (0.3 + x) / (0.1 - x) = 10^{-9.3}$

$x = 1.67 \times 10^{-10} \; \text{M} \approx 0 \; \text{M}$

$[\text{OH}^{-}] = 0.30 +x \approx 0.30 \; \text{M}$

$pH = pK_{w} - pOH = 14 + \text{log}_{10}[\text{OH}^{-}] = 14 + \text{log}_{10}{0.30} = 13.5$

6 0

2 years ago

Ap sublevel has 3 electrons. How should they be arranged

galina1969 [7]

Answer:

C.)One electron in each p orbital

Explanation:

In a P-sublevel with 3 electrons, they should be arranged with one electron going into each p-orbitals.

This is in accordance with the Hund's rule of maximum multiplicity.

The rule states that "electrons go into degenerate orbitals or sub-levels(p,d and f) singly before paring up".

Since the p-orbital is 3-fold degenerate with a capacity to accommodate a maximum number of 6 electrons, given 3 electrons, they will follow the Hund's rule in order to fill the orbitals.

So one electron will go in each p - orbitals easily.

4 0

2 years ago

Which is a substance that could be found in air, water, or soil that is harmful to humans or animals? carbon dioxide fossil fuel

quester [9]

Hi!

The substance that could be found in air, water or soil that is harmful to humans or animals is called pollutant.

Pollutants are the only harmful substances that can be found in these three places. Carbon Dioxide (CO₂) is commonly found in the air, fossil fuels are found in soil and water and smog is found in the air. Only pollutant can be found in these three places as there are varied in its chemical structure. Common pollutants include Sulfur Dioxide (SO₂) which can be found in the air, and Lead, which can be found in water or soil.

Have a nice day!

4 0

3 years ago

1) How does the oxpecker benefit?

Bezzdna [24]

Explanation:

1)

Oxpeckers are a type of small bird that land on zebras and eat ticks and other parasites that live on the zebra's skin. The oxpeckers get food and the zebras get pest control. ... Tapeworms get food by eating the host's partly digested food, depriving the host of nutrients.

2)i. Fast Speed. Basically, we can process data that is stored in HDFS at lightning-fast speed with traditional SQL knowledge, by using Impala.

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vi. Big Data. ...

vii. Relational model. ...

viii. Languages.

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In the Internet, a hostname is a domain name assigned to a host computer. ... For example, en.wikipedia.org consists of a local hostname (en) and the domain name wikipedia.org. This kind of hostname is translated into an IP address via the local hosts file, or the Domain Name System (DNS) resolver.

4) Usually, although parasites harm their hosts, it is in the parasite's best interest not to kill the host, because it relies on the host's body and body functions, such as digestion or blood circulation, to live. Some parasitic animals attack plants.

5)The pollen sticks to the hummingbird and as the hummingbird goes to another cardinal flower for food the pollen is spread. This would qualify as a mutual relationship because both of the organisms benefit from the relationship. ... These two organisms have a relationship that is known as mutualism.

6)According to Campbell, moose populations are highest in areas 40 years after a major wildfire. But habitat loss is not the only probable cause of moose decline. Tiny ticks also could be a big problem. ... Without deep snow, then predators like wolves and mountain lions have an advantage over moose.”

Deforestation Led to Decline

The reasons why wolves have seen their population decimated mainly due to the diminishing forests in North America, where many of the wolves are found. Wolves were able to live in and survive in such an environment.

5 0

2 years ago