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3 years ago

An atom of oxygen has atomic of 8 and a mass number of 18. How many of each type of subatomic particle doe it contain?

1 answer:

7 0

An atom of Oxygen. Contains:

Protons = 8
Electrons = 8

Neutrons = Mass number - Number of protons = 18 - 8 = 10

Neutrons = 10.

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What part of a refracting telescope would you measure to find the aperture? *

andrezito [222]

Answer:

Objective

Optics

For an optical instrument, the aperture is the diameter of the objective lens (refracting telescope) or the primary mirror (reflecting telescope). The larger the aperture, the more light the telescope can gather, and the fainter the limiting magnitude of the instrument.

Explanation:

6 0

3 years ago

Read 2 more answers

weather balloon is filled with helium to a volume of 340 L at 30 ∘C and 751 mmHg . The balloon ascends to an altitude where the

valentinak56 [21]

Answer: Thus the volume of the balloon at this altitude is 419 L

Explanation:

Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.

The combined gas equation is,

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$

where,

$P_1$ = initial pressure of gas = 751 mm Hg

$P_2$ = final pressure of gas = 495 mm Hg

$V_1$ = initial volume of gas = 340 L

$V_2$ = final volume of gas = ?

$T_1$ = initial temperature of gas = $30^oC=273+30=303K$

$T_2$ = final temperature of gas = $-27^oC=273-27=246K$

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

$\frac{751\times 340}{303}=\frac{495\times V_2}{246}$

$V_2=419L$

Thus the volume of the balloon at this altitude is 419 L

8 0

3 years ago

4. Magnesium and oxygen undergo a chemical reaction to

erastovalidia [21]

Answer:

About 16.1 grams of oxygen gas.

Explanation:

The reaction between magnesium and oxygen can be described by the equation:
$\displaystyle 2\text{Mg} + \text{O$_2$} \longrightarrow 2\text{MgO}$

24.4 grams of Mg reacted with O₂ to produce 40.5 grams of MgO. We want to determine the mass of O₂ in the chemical change.

Compute using stoichiometry. From the equation, we know that two moles of MgO is produced from every one mole of O₂. Therefore, we can:

Convert grams of MgO to moles of MgO.
Moles of MgO to moles of O₂
And moles of O₂ to grams of O₂.

The molecular weights of MgO and O₂ are 40.31 g/mol and 32.00 g/mol, respectively.

Dimensional analysis:

$\displaystyle 40.5\text{ g MgO} \cdot \frac{1\text{ mol MgO}}{40.31\text{ g MgO}} \cdot \frac{1\text{ mol O$_2$}}{2\text{ mol MgO}} \cdot \frac{32.00\text{ g O$_2$}}{1\text{ mol O$_2$}} = 16.1\text{ g O$_2$}$

In conclusion, about 16.1 grams of oxygen gas was reacted.

You will obtain the same result if you compute with the 24.4 grams of Mg instead:

$\displaystyle 24.4\text{ g Mg}\cdot \frac{1\text{ mol Mg}}{24.31\text{ g Mg}} \cdot \frac{1\text{ mol O$_2$}}{1\text{ mol Mg}} \cdot \frac{32.00\text{ g O$_2$}}{1\text{ mol O$_2$}} = 16.1\text{ g O$_2$}$

3 0

2 years ago

Calculate the eccentricity of an ellipse. The distance between the foci is 5.2 and the length of the major axis is 20.6.Round of

Dominik [7]

Answer:

The eccentricity of the ellipse is 0.252.

Explanation:

The eccentricity of an ellipse ( $c$ ), dimensionless, can be determined by means of the following expression:

$e = \frac{\bar c}{\bar a}$ (1)

Where:

$\bar c$ - Distance between the foci, dimensionless.

$\bar a$ - Length of the major axis, dimensionless.

If we know that $\bar c = 5.2$ and $\bar a = 20.6$ , then the eccentricity of the ellipse is:

$e = \frac{5.2}{20.6}$

$e = 0.252$

The eccentricity of the ellipse is 0.252.

8 0

3 years ago

Consider the following system at equilibrium where H° = 16.1 kJ, and Kc = 6.50×10-3, at 298 K. 2NOBr(g) 2NO(g) + Br2(g)If the VO

Norma-Jean [14]

Answer:

1) The value of Kc : (C.) remains the same

2) The value of Qc : (A.) is greater than Kc

3) The reaction must : (B.) run in the reverse direction to reestablish equilibrium.

4) The number of moles of Br2 will : (B.) decrease

Explanation:

Value of concentration equilibrium constant Kc depends only on temperature. Since temperature remains constant, therefore, Kc remains constant. Decrease in volume means increase in pressure. Increase in pressure favors the side with less gaseous species. Hence, increase in pressure will favor the reverse reaction towards reactants.

7 0

3 years ago