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1 year ago

In the preceding information section there is a "bohr's diagram" of an atom. Which atom is it?

Chemistry

1 answer:

dsp731 year ago

5 0

Bohr's atomic model may have not been the accurate atomic model we have in the present, but he helped paved the way for accurate discoveries. His model is also called the planetary model. The nucleus, containing the neutrons and protons are situated at the center of the atom. The electrons are orbiting around the nucleus. The model is illustrated as shown in the attached picture.

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Which air mass has formed immediately north of Antarctica in the image?

hammer [34]

Answer:

Maritime Polar

5 0

1 year ago

Read 2 more answers

Suppose a group of volunteers is planning to build a park near a local lake. The lake is known to contain low levels of arsenic

Kisachek [45]

Answer:

A) 10.75 is the concentration of arsenic in the sample in parts per billion .

B) 7,633.66 kg the total mass of arsenic in the lake that the company have to remove.

C) It will take 1.37 years to remove all of the arsenic from the lake.

Explanation:

A) Mass of arsenic in lake water sample = 164.5 ng

The ppb is the amount of solute (in micrograms) present in kilogram of a solvent. It is also known as parts-per million.

To calculate the ppm of oxygen in sea water, we use the equation:

$\text{ppb}=\frac{\text{Mass of solute}}{\text{Mass of solution}}\times 10^9$

Both the masses are in grams.

We are given:

Mass of arsenic = 164.5 ng = $164.5\times 10^{-9} g$

$1 ng=10^{-9} g$

Volume of the sample = V = $15.3 cm^3$

Density of the lake water sample ,d= $1.00 g/cm^3$

Mass of sample = M = $d\times V=1.0 g/cm^3\times 15.3 cm^3=15.3 g$

$ppb=\frac{164.5\times 10^{-9} g}{15.3 g}\times 10^9=10.75$

10.75 is the concentration of arsenic in the sample in parts per billion.

Mass of arsenic in $1 cm^3$ of lake water = $\frac{164.5\times 10^{-9} g}{15.3}=1.075\times 10^{-8} g$

Mass of arsenic in $0.710 km^3$ lake water be m.

$1 km^3=10^{15} cm^3$

Mass of arsenic in $0.710\times 10^{15} cm^3$ lake water :

$m=0.710\times 10^{15}\times 1.075\times 10^{-8} g=7,633,660.130 g$

1 g = 0.001 kg

7,633,660.130 g = 7,633,660.130 × 0.001 kg=7,633.660130 kg ≈ 7,633.66 kg

7,633.66 kg the total mass of arsenic in the lake that the company have to remove.

Company claims that it takes 2.74 days to remove 41.90 kilogram of arsenic from lake water.

Days required to remove 1 kilogram of arsenic from the lake water :

$\frac{2.74}{41.90} days$

Then days required to remove 7,633.66 kg of arsenic from the lake water :

$=7,633.66\times \frac{2.74}{41.90} days=499.19 days$

1 year = 365 days

499.19 days = $\frac{499.19}{365} years = 1.367 years\approx 1.37 years$

It will take 1.37 years to remove all of the arsenic from the lake.

3 0

1 year ago

Consider four beakers labeled A, B, C, and D, each containing an aqueous solution and a solid piece of metal. Identity the beake

Anna71 [15]

Answer:

A Reaction

3. Pt(NO₃)₂(aq) + Cu(s)

4. Cr(s) + H₂SO₄(aq)

B Non Reaction

1. Mn(s) + Ca(NO₃)₂(aq)

2. KOH(aq) + Fe(s)

Y > Q > W > Z > X

Explanation:

The first question is whether a reaction will occur base on the chemical equation below.

1. Mn(s) + Ca(NO₃)₂(aq)

2. KOH(aq) + Fe(s)

3. Pt(NO₃)₂(aq) + Cu(s)

4. Cr(s) + H₂SO₄(aq)

Firstly, some element are more reactive than others , base on this criteria element can be arranged base on it reactivity .

1. Mn(s) + Ca(NO₃)₂(aq)

This reaction will not occur because Mn cannot displace Ca in it compound. Usually, more reactive element displaces less reactive element.

2. KOH(aq) + Fe(s)

The reaction will not occur since Iron is less reactive and lower in the reactivity series than potassium . So iron won't be able to displace potassium.

3. Pt(NO₃)₂(aq) + Cu(s)

Copper is more reactive than platinum so it will displace platinum easily . The reaction will definitely occur.

4. Cr(s) + H₂SO₄(aq)

Chromium is higher up in the reactivity series than hydrogen so, it will definitely displace hydrogen in it compound . The reaction will occur in this case.

Base on the reaction

Q + W+ Reaction occurs

Since the reaction occurred element Q is more reactive as it displace element w from it compound.

X + Z+ No reaction

No reaction occurred because element x is less reactive than z therefore, it cannot displace z from it compound.

W + Z+ Reaction occurs

Element w is more reactive than z as it displaces z form it compound.

Q+ + Y Reaction occurs

Element Y is more reactive than element Q as it displaces Q from it compound.

Therefore, the order of reactivity from the most reactive to the least reactive will be Y > Q > W > Z > X

3 0

2 years ago

Calculate the maximum concentration (in m) of silver ions (ag+) in a solution that contains 0.025 m of co32-. the ksp of ag2co3

Helen [10]

Equilibrium equation is

Ag2CO3(s) <---> 2 Ag+(aq) + CO32-(aq) 

From the reaction equation above, the formula for Ksp: 

Ksp = [Ag+]^2 [CO32-] = 8.1 x 10^-12 
You know [CO32-], so you can solve for [Ag+] as: 
(8.1 x 10^-12) = [Ag+]^2 (0.025) 
[Ag+]^2 = 3.24 x 10^-10 
[Ag+] = 1.8 x 10^-5 M

5 0

2 years ago

According to the following reaction, how many grams of chloric acid (HClO3) are produced in the complete reaction of 31.6 grams

gogolik [260]

Answer:

$m_{HClO_3}=12.7gHClO_3$

Explanation:

Hello,

Considering the reaction:

$3Cl_2(g)+3H_2O(l)-->5HCl+HClO_3$

The molar masses of chlorine and chloric acid are:

$M_{Cl_2}=35.45*2=70.9g/mol\\M_{HClO_3}=1+35.45+16*3=84.45g/mol$

Now, we develop the stoichiometric relationship to find the mass of chloric acid, considering the molar ratio 3:1 between chlorine and chloric acid, as follows:

$m_{HClO_3}=31.6gCl_2*\frac{1molCl_2}{70.9gCl_2} *\frac{1molHClO_3}{3mol Cl_2} *\frac{85.45g HClO_3}{1mol HClO_3} \\m_{HClO_3}=12.7gHClO_3$

Best regards.

4 0

2 years ago