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2 years ago

Astronomers initially had difficulty identifying the emission lines in quasar spectra at optical wavelengths because

Physics

1 answer:

Rus_ich [418]2 years ago

6 0

No one expected violet & ultraviolet spectral lines to be shifted towards the red.

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A metal, M, forms an oxide having the formula M2O3 containing 52.92% metal by mass. Determine the atomic weight in g/mole of the

irina [24]

Answer:

The atomic weight in g/mole of the metal (molar mass) is 8.87.

Explanation:

To begin, it is possible to assume that, as a sample, it has 100 g of the compound. This means that:

52.92% metal: 52.92 g M
47.80% oxygen: 47.80 g O

Using the molar mass of oxygen, which is 16 g / mol, it is possible to calculate the amount of moles of oxygen present in the sample using the rule of three:

$moles of oxygen=\frac{47.8g*1mol}{16g}$

moles of oxygen=2.9875

The chemical formula of metal oxide tells you that:

2 M⁺³ + 3 O²⁻ ⇒ M₂O₃

In the previous equation you can see that you need 3 oxygen anions to react with two metal cations. Then:

$2.9875 moles of oxygen*\frac{2 moles of metal M}{1 mol of oxygen} = 5.975 moles of metal M$

You have 52.92 g of metal in the sample, then the molar mass of the metal is:

$molar mass=\frac{52.92 g}{5.975 mol}$

molar mass≅ 8.87 g/mol

The atomic weight in g/mole of the metal (molar mass) is 8.87.

The closest match to this value is Beryllium (Be), which has an atomic mass of 9.0122 g / mol.

3 0

2 years ago

A confused dragonfly flies forward and backward in a straight line. Its motion is shown on the following graph of horizontal pos

sertanlavr [38]

Answer:

Explanation:

Assuming your graph and question match the attachment, the average speed is 0. The bug ends up where it started, so its displacement is zero.

average speed = displacement/time = 0/(8 s)

average speed = 0

7 0

2 years ago

You have been abducted by aliens and find yourself on a strange planet. Fortunately, you have a meter stick with you. You observ

defon

Answer:

$36.4276\ m/s^2$

Explanation:

m = Mass of stick

L = Length of stick = 1 m

h = Center of mass of stick = $\dfrac{1}{2}=0.5\ m$

g = Acceleration due to gravity

T = Time period = 0.85 s

Time period is given by

$T=2\pi\sqrt{\dfrac{I}{mgh}}$

Moment of inertia is given by

$I=m\dfrac{L^2}{3}$

$T=2\pi\sqrt{\dfrac{m\dfrac{L^2}{3}}{mgh}}\\\Rightarrow T=2\pi\sqrt{\dfrac{L^2}{3gh}}\\\Rightarrow g=\dfrac{4\pi^2L^2}{3hT^2}\\\Rightarrow g=\dfrac{4\pi^2\times 1^2}{3\times 0.5\times 0.85^2}\\\Rightarrow g=36.4276\ m/s^2$