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3 years ago

What is group 18 of the periodic table called?

Chemistry

2 answers:

Korolek [52]3 years ago

4 0

Group 18 is known as the Noble/ Inert Gases

Stolb23 [73]3 years ago

4 0

Group 18 is called the noble glass

Sorry If I am wrong

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Which of the following are characteristics of a protein? Select all that apply. A. It is made of amino acids. B. It has long cha

gayaneshka [121]

I believe the answers are A and D

3 0

2 years ago

Calculate the energy of one photon of yellow light that has a wavelength of 5.89x10^-7m.

Viktor [21]

Answer:

E = energy = ? ,

λ = Wavelength = 5.89 × 10^-7 m —> = 589 ×10 ^-9 m ,

h =Planck constant = 6.63 × 10^-34 J.s ,

f = frequency of photo/ electromagnetic radiation = c/λ ,

c = Speed of light in a vacuum = 3 × 10^8 m/s

___o___o____

$E = hf \\ \\ E = h \frac{c}{λ} \\ \\ E = 6.63 \times {10}^{ - 34} \frac{3 \times {10}^{8} }{5.89 \times {10}^{ - 7} } \\ \\E = \frac{6.63 \times {10}^{ - 34} \times 3 \times {10}^{8} }{5.89 \times {10}^{ - 7} } \\ \\ E = \frac{663 \times {10}^{ - 36} \times 3 \times {10}^{8} }{589 \times {10}^{ - 9} } \\ \\ E = \frac{1989 \times {10}^{ - 28} }{589 \times {10}^{ - 9} } \\ \\ E = 3.37691 \times {10}^{ - 19} J$

I hope I helped you^_^

8 0

2 years ago

When a 3.25 g sample of solid sodium hydroxide was dissolved in a calorimeter in 100.0 g of water, the temperature rose from 23.

sertanlavr [38]

Answer : The enthalpy change for the solution is 42.8 kJ/mol

Explanation :

Heat released by the reaction = Heat absorbed by the calorimeter + Heat absorbed by the water

$q=[q_1+q_2]$

$q=[c_1\times \Delta T+m\times c_2\times \Delta T]$

where,

q = heat released by the reaction

$q_1$ = heat absorbed by the calorimeter

$q_2$ = heat absorbed by the water

$c_1$ = specific heat of calorimeter = $15.8J/^oC$

$c_2$ = specific heat of water = $4.18J/g^oC$

$m$ = mass of water = 100.0 g

$\Delta T$ = change in temperature = $T_2-T_1=(32.0-23.9)=8.1^oC$

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

$q=[(15.8J/^oC\times 8.1^oC)+(100.0g\times 4.18J/g^oC\times 8.1^oC)]$

$q=3513.8J=3.5138kJ$ (1 kJ = 1000 J)

Now we have to calculate the enthalpy change for the solution.

$\Delta H=\frac{q}{n}$

where,

$\Delta H$ = enthalpy change = ?

q = heat released = 3.5138 kJ

m = mass of NaOH = 3.25 g

Molar mass of NaOH = 40 g/mole

$\text{Moles of }NaOH=\frac{\text{Mass of }NaOH}{\text{Molar mass of }NaOH}=\frac{3.25g}{40g/mole}=0.0812mole$

Now,

$\Delta H=\frac{3.5138kJ}{0.0821mole}=42.8kJ/mol$

Therefore, the enthalpy change for the solution is 42.8 kJ/mol

4 0

2 years ago

What do you think will happen by adding cold seawater to "your ocean”

Contact [7]

Answer:

it will be troubled and won't have peace

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2 years ago

3. What detrmines the identity of an atom?

Brrunno [24]

The number of protons in one atom of an element determines the atom's identity, and the number of electrons determines its electrical charge. The atomic number tells you the number of protons in one atom of an element. ... The atomic mass of an element is the total number of protons and neutrons in the nucleus of the atom.

5 0

2 years ago