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3 years ago

Periods on the periodic table are

Chemistry

1 answer:

Roman55 [17]3 years ago

6 0

Answer:

Periods on the periodic table of elements

Explanation:

In the periodic table of elements, there are seven horizontal rows of elements called periods. The vertical columns of elements are called groups, or families. (See also The Periodic Table: Metals, Nonmetals, and Metalloids.) In each period (horizontal row), the atomic numbers increase from left to right.

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The frequency of an x-ray wave is 3.0 x 1012MHz. Its wave speed is 3.0x 108m/s. Calculate the wavelength of the x-ray wave below

jasenka [17]

Answer: The wavelength of the x-ray wave is $10^{-10}m$

Explanation:

To calculate the wavelength of light, we use the equation:

$\lambda=\frac{c}{\nu}$

where,

$\lambda$ = wavelength of the light = ?

c = speed of x-ray= $3.0\times 10^8m/s$

$\nu$ = frequency of x-ray = $3.0\times 10^{12}MHz=3.0\times 10^{18}Hz= 3.0\times 10^{18}s^{-1}$ $(1Hz=1s^{-1})$

Putting in the values:

$\lambda=\frac{3.0\times 10^8m/s}{3.0\times 10^{18}s^{-1}}=10^{-10}m$

Thus the wavelength of the x-ray wave is $10^{-10}m$

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3 years ago

How important is it for scientists and engineers to be able to control the design of

Hatshy [7]

It is important for scientists and engineers to be able to control the design of the material because<u> it create solutions to problems</u>.

<h3>Why material science and engineering is important?</h3>

What things are made of and why they behave the way they do are lessons we learn from materials science. Materials engineering teaches us how to use knowledge to improve things and the way they are made. Research and industry innovation in fields as diverse as aerospace and medicine are driven by materials science and engineering.

<h3>Why is it important for scientists to use the scientific method?</h3>

The scientific method is essential because: It follows a set of rules. Scientists conduct experiments in a standardized manner because the steps used in the scientific method are systematic. This suggests that their research might be spread widely.

To know more about aerospace :

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4 0

1 year ago

If a lab experiment is not completed, you should:___________.

stellarik [79]

The answer to this question is a

7 0

3 years ago

Read 2 more answers

What property is not a characteristic of metals? Brittle Shiny Ductile Malleable

MrMuchimi

Answer:

brittle is not a characteristic of metals

3 0

2 years ago

Read 2 more answers

The constant

Zigmanuir [339]

Answer:

75 kJ/mol

Explanation:

The reactions occur at a rate, which means that the concentration of the reagents decays at a time. The rate law is a function of the concentrations and of the rate constant (k) which depends on the temperature of the reaction.

The activation energy (Ea) is the minimum energy that the reagents must have so the reaction will happen. The rate constant is related to the activation energy by the Arrhenius equation:

ln(k) = ln(A) -Ea/RT

Where A is a constant of the reaction, which doesn't depend on the temperature, R is the gas constant (8.314 J/mol.K), and T is the temperature. So, for two different temperatures, if we make the difference between the two equations:

ln(k1) - ln(k2) = ln(A) - Ea/RT1 - ln(A) + Ea/RT2

ln (k1/k2) = (Ea/R)*(1/T2 - 1/T1)

k1 = 8.3x10⁸, T1 = 142.0°C = 415 K

k2 = 6.9x10⁶, T2 = 67.0°C = 340 K

ln(8.3x10⁸/6.9x10⁶) = (Ea/8.314)*(1/340 - 1/415)

4.8 = 6.39x10⁻⁵Ea

Ea = 75078 J/mol

Ea = 75 kJ/mol

4 0

3 years ago