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3 years ago

An atom has 18 protons and 8 valence electrons which statement would best identify this element

Chemistry

2 answers:

lorasvet [3.4K]3 years ago

7 0

Argon has 18 protons which identifies the element and is in group Noble Gases which has 8 valence electrons.

fgiga [73]3 years ago

3 0

It would argon because the atomic number is the same as the protons.

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A ________ is an electric circuit that produces a magnetic field

aksik [14]

I believe it would be D. Electromagnet. It's been a while since I've done this stuff, tho. Hope this helps!!!! :)

5 0

3 years ago

A rigid tank contains 1.40 moles of an ideal gas. Determine the number of moles of gas that must be withdrawn from the tank to l

sergey [27]

Answer : The final number of moles of gas that withdrawn from the tank to lower the pressure of the gas must be, 0.301 mol.

Explanation :

As we know that:

$PV=nRT$

At constant volume and temperature of gas, the pressure will be directly proportional to the number of moles of gas.

The relation between pressure and number of moles of gas will be:

$\frac{P_1}{P_2}=\frac{n_1}{n_2}$

where,

$P_1$ = initial pressure of gas = 24.5 atm

$P_2$ = final pressure of gas = 5.30 atm

$n_1$ = initial number of moles of gas = 1.40 moles

$n_2$ = final number of moles of gas = ?

Now put all the given values in the above expression, we get:

$\frac{24.5atm}{5.30atm}=\frac{1.40mol}{n_2}$

$n_2=0.301mol$

Therefore, the final number of moles of gas that withdrawn from the tank to lower the pressure of the gas must be, 0.301 mol.

8 0

2 years ago

For a lake in Michigan, researchers have determined that largemouth bass feed on smaller fish, which in turn feed on zooplankton

allsm [11]

Answer:

the expected decline in largemouth bass is 3,000 kg.

Option d) 3,000 kg is the correct answer.

Explanation:

Given the data in the question;

In 2016, there was 600,000 kg of zooplankton in the lake.

In 2017, an accidental runoff of insecticide near the lake caused a 50 percent decline of the zooplankton population in the lake.

Now,

The remaining mass of zooplankton after the 50% decline will be;

⇒ 600,000 kg zooplankton × 50%

⇒ 600,000 × 50/100

⇒ 300,000 kg of zooplankton

Now, with 10 percent trophic efficiency; smaller fish directly feed on zooplankton; decline in smaller fish mass will be;

⇒ 300,000 kg × 10%

⇒ 300,000 × 10/100

⇒ 30000 kg

Finally, with 10 percent trophic efficiency, largemouth bash directly feed on smaller fish, so the expected decline in mass of largemouth bash will be;

⇒ 30000 kg × 10%

⇒ 30000 kg × 10/100

⇒ 3,000 kg

Therefore, the expected decline in largemouth bass is 3,000 kg.

Option d) 3,000 kg is the correct answer.

7 0

3 years ago

A.Which facilities contribute the most to recycling and the least to recycling based on the pie chart graphic?

nirvana33 [79]

Answer:

a) To determine the facilities that contribute the most to recycling check the pie chart and select the facility with the largest portion while to determine the facilities that contribute the least to recycling check the pie chart and select the facility with the smallest portion

b) Energy is saved because the products which are recycled usually require less energy to turn them into usable materials

c) It saves energy through recycling. It helps sustains the environment. It decrease the emission of green house gases

Explanation:

The question is not complete

a) Pie chart is the graphical representation of information in which the information is represented in a circle. The circle is divided into segments and the portion with the largest segment has the highest percentage.

To determine the facilities that contribute the most to recycling check the pie chart and select the facility with the largest portion while to determine the facilities that contribute the least to recycling check the pie chart and select the facility with the smallest portion

b) Extraction and processing of raw resources to make end products requires a lot of energy. With recycling energy is saved because the products which are recycled usually require less energy to turn them into usable materials

c) It saves energy through recycling. It helps sustains the environment. It decrease the emission of green house gases.

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3 years ago

1) Which of the following is the best example of a physical change?

never [62]

1 is b and 2 is also b

4 0

3 years ago