All categories

2 years ago

Why is the Universal Law of Gravitation is a scientific Law and not a theory?

1 answer:

5 0

This is a law because it describes the force but makes not attempt to explain how the force works. A theory is an explanation of a natural phenomenon. Einstein's General Theory of Relativity explains how gravity works by describing gravity as the effect of curvature of four dimensional spacetime.

You might be interested in

The mass of a single uranium atom is 4.70x10^-22 grams. How many uranium atoms would there be in 111 milligrams of uranium?

emmainna [20.7K]

2.4 x 10²² atoms

<h3>Further explanation</h3>

Atomic mass is the average atomic mass of all its isotopes

In determining the mass of an atom, as a standard is the mass of 1 carbon-12 atom whose mass is 12 amu

So the atomic mass obtained is the mass of the atom relative to the 12th carbon atom

mass single Uranium atom=4.7 x 10⁻²² g

then for 111 mg=0.111 g

$\tt \dfrac{0.111}{4.7\times 10^{-22}}=2.4\times 10^{22}$

5 0

3 years ago

Why are stars special sources of light?(2 points)

Alex787 [66]

Answer:

They give off their own light energy

Explanation:

I'm taking astronomy and I answered this questions not too long ago

8 0

3 years ago

If you have access to stock solutions of 1.00 M H3PO4, 1.00 M of HCl, and 1.00 M NaOH solution, (and distilled water of course),

garri49 [273]

Answer:

0.10L of 1.00M of H₃PO₄ and 0.1613L of 1.00M NaOH

Explanation:

The pKa's of phosphoric acid are:

H₃PO₄/H₂PO₄⁻ = 2.1

H₂PO₄⁻/HPO₄²⁻ = 7.2

HPO₄²⁻/PO₄³⁻ = 12.0

To make a buffer with pH 9.40 we need to convert all H₃PO₄ to H₂PO₄⁻ and an amount of H₂PO₄⁻ to HPO₄²⁻

To have a 50mM solution of phosphoures we need:

2L * (0.050mol / L) = 0.10 moles of H₃PO₄

0.10 mol * (1L / mol) = 0.10L of 1.00M of H3PO4

To convert the H₃PO₄ to H₂PO₄⁻ and to HPO₄²⁻ must be added NaOH, thus:

H₃PO₄ + NaOH → H₂PO₄⁻ + H₂O + Na⁺

H₂PO₄⁻ + NaOH → HPO₄²⁻ + H₂O + Na⁺

Using H-H equation we can find the amount of NaOH added:

pH = pKa + log [A⁻] / [HA] (1)

Where [A-] is conjugate base, HPO₄²⁻ and [HA] is weak acid, H₂PO₄⁻

pH = 7.40

pKa = 7.20

[A-] + [HA] = 0.10moles (2)

Replacing (2) in (1):

7.40 = 7.20 + log 0.10mol - [HA] / [HA]

0.2 = log 0.10mol - [HA] / [HA]

1.5849 = 0.10mol - [HA] / [HA]

1.5849 [HA] = 0.10mol - [HA]

2.5849[HA] = 0.10mol

[HA] = 0.0387 moles = H₂PO₄⁻ moles

That means moles of HPO₄²⁻ are 0.10mol - 0.0387moles = 0.0613 moles

The moles of NaOH needed to convert all H₃PO₄ in H₂PO₄⁻ are 0.10 moles

And moles needed to obtain 0.0613 moles of HPO₄²⁻ are 0.0613 moles

Total moles of NaOH are 0.1613moles * (1L / 1mol) = 0.1613L of 1.00M NaOH

Then, you need to dilute both solutions to 2.00L with distilled water.

4 0

3 years ago

What is the mass of 6.02 x 1022 atoms of Xenon? HELP!!!!!

il63 [147K]

So 6.02*10^22 is avogadro constant, which is the amount of atoms in one mole. If you look Xenon up in the periodic table you will find it's mass given 131,293, which is grams per 1 mole.

8 0

3 years ago

What would happen to the water’s boiling point if MgSO4 is added to it?

kirill [66]

Answer:

When Epsom salt (magnesium sulfate) dissolves, it separates into its ions: a magnesium ion (Mg2+) and a sulfate ion (SO4 2-), which results in hard water. When hard water and soap are mixed, the magnesium ion reacts with soap molecules and forms a solid material called a precipitate, which does not dissolve.

Explanation:

can i have brainlest

4 0

3 years ago