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3 years ago

What elements are in the star sirius?

Chemistry

1 answer:

ziro4ka [17]3 years ago

3 0

Answer:

Sirius B is primarily made out of a carbon-oxygen mixture that was generated by helium fusion in the progenitor star. The outer atmosphere is now almost pure hydrogen, the element with the lowest mass.

Explanation:

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Calculate the mass of ethylene glycol (C2H6O2) that must be added to 1.00 kg of ethanol (C2H5OH) to reduce its vapor pressure by

Diano4ka-milaya [45]

Answer:

183.7 g of ethylene glycol

Explanation:

This a case of colligative property, about vapour pressure lowering.

ΔPv = P° . Xst

ΔPv = 12 Torr

P° = Vapour pressure of pure solvent → 100 Torr

12 Torr = 100 Torr . Xst

12 Torr / 100 Torr = 0.12 → Xst

Xst is mole fraction for solute which means moles of solute / Total moles and, the total moles are the sum of moles of solvent + moles of solute.

We can make this equation:

Moles of solute / (Moles of solute + Moles of solvent) = 0.12

We don't know the moles of solute, but we do know the moles of solvent by the mass.

Mass / Molar mass = Mol

1000 g / 46 g/m = 21.7 moles

Moles of solute / Moles of solute + 21.7 moles = 0.12

Moles of solute = 0.12 ( Moles of solute + 21.7 moles)

Moles of solute - 0.12 moles of solute = 2.60 moles

0.88 moles of solute = 2.60 moles

Moles of solute = 2.60 moles / 0.88 → 2.96 moles of solute

Mol . molar mass = Mass

2.96 m . 62g/m = 183.7 g

4 0

3 years ago

Classify the following bonds as ionic, covalent, or neither (O, atomic number 8; F, atomic number 9; Na, atomic number 11; Cl, a

mylen [45]

Answer:

1. Oxygen Fluoride (O with F): covalent

2. Calcium Chloride (Ca with Cl): ionic

3. Sodium with Sodium (Na with Na): neither

Explanation:

1. Oxygen Fluoride (OF2)

Oxygen with Fluorine is covalent because both of these elements are nonmetals. Bonds that contain only nonmetals are covalent.

2. Calcium Chloride (CaCl2)

Calcium with Chlorine is ionic because there is one metal and one nonmetal. Bonds that contain one metal and one nonmetal are ionic.

3. Sodium with Sodium

Since this is not Sodium bonding with another element, it is neither ionic or covalent.

6 0

3 years ago

Compare and contrast mutualism and commnsalism. For both relationships, explain who does or does not benefit and who is or is no

OlgaM077 [116]

Answer:

Mutualism is the symbiotic relationship where both organisms in the relationship benefit. An example of this is with clown fish and sea anemones.

Commensalism is the symbiotic relationship where one organism benefits and the other is unaffected/unharmed. An example of this is with barnacles (benefit) on a whale (unaffected).

7 0

3 years ago

What volume (mL) of 0.135 M NaOH is required to neutralize 13.7 mL of 0.129 M HCl? a: 0.24 b: 13.1 c: 0.076 d: 6.55 e: 14.3

Len [333]

Answer:

The volume (mL) of 0.135 M NaOH that is required to neutralize 13.7 mL of 0.129 M HCl is 13.1 mL (option b).

Explanation:

The reaction between an acid and a base is called neutralization, forming a salt and water.

Salt is an ionic compound made up of an anion (positively charged ion) from the base and a cation (negatively charged ion) from the acid.

When an acid is neutralized, the amount of base added must equal the amount of acid initially present. This base quantity is said to be the equivalent quantity. In other words, at the equivalence point the stoichiometry of the reaction is exactly fulfilled (there are no limiting or excess reagents), therefore the numbers of moles of both will be in stoichiometric relationship. So:

V acid *M acid = V base *M base

where V represents the volume of solution and M the molar concentration of said solution.

In this case:

V acid= 13.7 mL= 0.0137 L (being 1,000 mL= 1 L)
M acid= 0.129 M
V base= ?
M base= 0.135 M

Replacing:

0.0137 L* 0.129 M= V base* 0.135 M

Solving:

$V base=\frac{0.0137 L*0.129 M}{0.135 M}$

V base=0.0131 L = 13.1 mL

The volume (mL) of 0.135 M NaOH that is required to neutralize 13.7 mL of 0.129 M HCl is 13.1 mL (option b).

4 0

3 years ago

As atoms get smaller,valance electrons are getting closer or farther away from the nucleous.The force of attraction is stronger

LiRa [457]

Explanation:

Electrons are closer to the nucleus are in filled orbitals and are called core electrons. More energy which in nucleus called nuclear strOng energy to remove electron thars why its also a way harder too..

3 0

2 years ago