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3 years ago

Please please help me i’m so confused! i will give brainleiest answer

Chemistry

1 answer:

pochemuha3 years ago

7 0

Answer:

PLEASE MARK AS BRAINLIEST!!

Explanation:

Calcium has an atomic number of 20 and an atomic mass of 40

The mass number of an isotope is the sum of the number of protons and neutrons in the atomic nucleus. The atomic number is the number of protons. The calcium-40 isotope has a mass number of 40 , and an atomic number of 20 , therefore it has 20 protons.

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Which of the following terms refers to the number of moles of solute per liter of solution?

Anika [276]

Molarity
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3 years ago

How many mL are 2.3 mol of CO2 at STP?

kupik [55]

Answer:

0.052mL

Explanation:

1mole of a gas occupy 22.4L.

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3 years ago

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The energy of a photon needed to cause ejection of an electron from a photoemissive metal is expressed as the sum of the binding

slega [8]

Answer:

$Binding\ energy=43.43\times 10^{-20}\ J$

Explanation:

Using the expression for the photoelectric effect as:

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$\nu_0=\frac {c}{\lambda_0}$

Applying the equation as:

$\frac {h\times c}{\lambda}=\frac {hc}{\lambda_0}+\frac {1}{2}\times m\times v^2$

Where,

h is Plank's constant having value $6.626\times 10^{-34}\ Js$

c is the speed of light having value $3\times 10^8\ m/s$

$\lambda$ is the wavelength of the light being bombarded

Given, $\lambda=4.00\times 10^{-7}\ m$

$\frac {hc}{\lambda_0}$ is the binding energy or threshold energy

$\frac {1}{2}\times m\times v^2$ is the kinetic energy of the electron emitted. = $6.26\times 10^{-20}\ J$

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$\frac{h\times c}{\lambda}=Binding\ Energy+Kinetic\ Energy$

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$\frac{19.878}{10^{19}\times \:4}\ J=Binding\ Energy+6.26\times 10^{-20}\ J$

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$Binding\ energy=43.43\times 10^{-20}\ J$

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3 years ago

What did you predict would be the effect on the coil from the battery and the magnet

Nutka1998 [239]

Answer:

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3 years ago

How can scientists practice ethical lab behavior?

olga55 [171]

Answer:

C. By being honest in recording the results of their own experiments

Explanation:

Honesty in recording results is ethical behaviour and the basis of scientific research.

A. is wrong. If you repeat the same experiment, you should always get the same result.

B. is wrong. Copying someone else's results is cheating and certainly unethical behaviour.

D. is wrong. Making up data is dishonest and unethical behaviour.

E. is wrong. Following your own instincts about safety procedures is unethical because your instincts may be wrong. following them may result in injury to yourself or to others.

7 0

3 years ago

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