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3 years ago

#1: Which of the following scientists came up with the first widely recognized atomic theory?

2 answers:

6 0

<span>Yes that answer is correct. John dalton was an english scientist who lived during the 18th and 19th centuries and he is most famous for proposing the modern first widely recognized atomic theory. But, it is thought that his theory is influenced by the ideas of another scientist called Bryan Higgins .</span>

svet-max [94.6K]3 years ago

3 0

Answer:

John Dalton

Explanation:

Done the topic

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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

ale4655 [162]

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

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.

6 0

2 years ago

Which answer choice best describes the difference between folded mountains and fault-block mountains?

melamori03 [73]

The answer is; C

In folding, when segments of Earth's crust are bent and doubled over, the sediments in between are form folds, since they are forced into a smaller space. This also occurs in converging plates boundaries.

Block Mountains occur when stress due to compression in the crust causes the hanging wall between a fault to move up relative to the footwall.

6 0

3 years ago

Read 2 more answers

How many liters of plasma are present in 8.5 pints?

stellarik [79]

Answer:

there are 4.0205 Litres of plasma in 8.5 pints

Explanation:

Recall that:

1 quart qt = 2 pints pt and 1 quart = 946 mL

∴ two pints will contain 946 mL

and one pint will be = 946 mL/2

= 473 mL

Similarly, 8.5 pints will contain 473 mL × 8.5 = 4020.5 mL

We know that :

1000 mL = 1 Litres

Hence 4020.5 mL = (4020.5 /1000)L

= 4.0205 Litres

Therefore, there are 4.0205 Litres of plasma in 8.5 pints

4 0

3 years ago

The fuel used to power the booster rockets on

Effectus [21]

Answer:

746 moles of H2O are been produced from 373 moles of Al.

Explanation:

For every 3 moles of aluminum, you get 6 moles of H2O (double). Therefore, every 373 moles of Al, you will get double as well, that is 746 m.

3 0

3 years ago

How many electrons does nitrogen (N) need to gain to have a stable outer electron shell

earnstyle [38]

It need "3 electrons" to have a stable electronic configuration.

'cause it has 5 electrons in it's outer shell & every atom needs 8 electrons. So, it requires 3 more!

Hope this helps!

7 0

2 years ago

Read 2 more answers