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3 years ago

Can yall plz help me!!!!!!!!!!!!

Chemistry

1 answer:

tankabanditka [31]3 years ago

6 0

Answer:

Axis

Anatomy

In anatomy, the second cervical vertebra of the spine is named the axis or epistropheus. By the atlanto-axial joint, it forms the pivot upon which the first cervical vertebra, which carries the head, rotates.

Rotation

A rotation is a circular movement of an object around a center of rotation. A three-dimensional object can always be rotated about an infinite number of imaginary lines called rotation axis. If the axis passes through the body's center of mass, the body is said to rotate upon itself, or spin.

Revolution

In political science, a revolution is a fundamental and relatively sudden change in political power and political organization which occurs when the population revolts against the government, typically due to perceived oppression or political incompetence.

Elliptic orbit

In astrodynamics or celestial mechanics, an elliptic orbit or elliptical orbit is a Kepler orbit with an eccentricity of less than 1; this includes the special case of a circular orbit, with eccentricity equal to 0. In a stricter sense, it is a Kepler orbit with the eccentricity greater than 0 and less than 1.

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True or false energy has no mass and takes up no space

ivanzaharov [21]

Answer:

False

Explanation:

Energy takes up space as mass is a form of energy and energy is always constant.

4 0

4 years ago

How does matter and energy cycle through an ecosystem?

Ostrovityanka [42]

Answer:

Explanation:

5 0

3 years ago

Washing soda is a hydrate of sodium carbonate. Elemental analysis of a sample of washing soda gave 4.20% C and 7.05% H. What is

kozerog [31]

Answer:

Na₂CO₃ · 10H₂O

Explanation:

The formula for sodium carbonate hydrate is:

Na₂CO₃ · xH₂O

The unknown "x" is the number of water molecules contained in the hydrate.

To find "x" we have to use the hydrogen percentage in the sample, 7.05 % H.

First we calculate the molecular weight of Na₂CO₃ · xH₂O:

molecular weight of Na₂CO₃ · xH₂O = 23 × 2 + 12 + 16 × 3 + 18x

molecular weight of Na₂CO₃ · xH₂O = 106 + 18x g/mole

Now we devise the fallowing reasoning tanking in account 1 mole of Na₂CO₃ · xH₂O:

if in 106 + 18x grams of Na₂CO₃ · xH₂O we have 2x grams of hydrogen

then in 100 grams of Na₂CO₃ · xH₂O we have 7.05 grams of hydrogen

106 + 18x = (100 × 2x) / 7.05

106 + 18x = 28.4x

106 = 28.4x - 18x

106 = 10.4x

x = 106 / 10.4

x = 10.2 ≈ 10

The formula for the washing soda is Na₂CO₃ · 10H₂O.

5 0

3 years ago

A 20.38 gram sample of cobalt is heated in the presence of excess sulfur. A metal sulfide is formed with a mass of 31.47 g. Dete

Viefleur [7K]

Answer: The empirical formula of the metal sulfide is $CoBr_{2}$ .

Explanation:

Given: Mass of metal = 20.38 g

Mass of metal sulfide = 31.47 g

Moles is the mass of a substance divided by its molar mass.

So, moles of cobalt (molar mass = 59 g/mol) are as follows.

$Moles = \frac{mass}{molarmass}\\= \frac{20.38 g}{59 g/mol}\\= 0.345 mol$

Moles of bromine (molar mass = 80 g/mol) are as follows.

$Moles = \frac{(31.47 - 20.38) g}{80 g/mol}\\= \frac{11.09 g}{80 g/mol}\\= 0.138 mol$

Now, the ratio of number of moles of cobalt and number of moles of bromine are as follows.

Moles of Co : Moles of Br = 1 : 2

Hence, the empirical formula is $CoBr_{2}$ .

Thus, we can conclude that the empirical formula of the metal sulfide is $CoBr_{2}$ .

6 0

3 years ago

What are homologous series<br>

Semenov [28]

Answer :

A homologous series is a family of hydrocarbons with similar chemical properties who share the same general formula. We will look at three hydrocarbon series: alkanes, alkenes and the cycloalkanes. Hydrocarbons are compounds that contain only hydrogen and carbon.

3 0

3 years ago