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3 years ago

Why does it make sense that Hydrogen and Helium would be the first elements to form in the Universe?

Chemistry

1 answer:

Illusion [34]3 years ago

8 0

Answer:

Explanation:

It makes sense because Helium and Hydrogen only hold 1 and 2 subsequent protons/neutrons and electrons. When the Big Bang happened the entire universe was so hot that it was impossible for elements to form since it was impossible for electrons to stay bound to the atoms. After a few seconds the universe began to cool enough for electrons to bond to atoms and create different elements. Since Helium and Hydrogen have 1 and 2 electrons subsequently we can assume that they were the first elements to be created. Also they are the most abundant elements in the Universe which backs up this theory.

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What is the molar mass of nickel (ll) chloride(NiCl2)

goldenfox [79]

Answer:

Explanation:

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3 years ago

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Which of the atoms below are least likely to violate the octet rule?

Levart [38]

Answer:

F i think i pretty sure F!!!!!!!!

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3 years ago

one reaction that produces hydrogen gas can be represented by the unbalanced chemical equation Mg(s)+HCI(aq) -> MgCI(aq)+H2(g

Sonbull [250]

<h3>Answer:</h3>

128 g HCl

<h3>General Formulas and Concepts:</h3>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right<u> </u>

<u>Chemistry</u>

<u>Atomic Structure</u>

Reading a Periodic Table

<u>Stoichiometry</u>

Reaction Mole Ratios
Using Dimensional Analysis

<h3>Explanation:</h3>

<u>Step 1: Define</u>

[RxN - Unbalanced] Mg (s) + HCl (aq) → MgCl (aq) + H₂ (g)

↓

[RxN - Balanced] 2Mg (s) + 2HCl (aq) → 2MgCl (aq) + H₂ (g)

[Given] 3.25 mol Mg

[Solve] x g HCl

<u>Step 2: Identify Conversions</u>

[RxN] 2 mol Mg → 2 mol HCl

[PT] Molar Mass of H - 1.01 g/mol

[PT] Molar Mass of Cl - 35.45 g/mol

Molar Mass of HCl - 1.01 + 35.45 = 36.46 g/mol

<u>Step 3: Stoich</u>

[S - DA] Set up: $\displaystyle 3.25 \ mol \ Mg(\frac{2 \ mol \ HCl}{2 \ mol \ Mg})(\frac{36.46 \ g \ HCl}{1 \ mol \ HCl})$
[S - DA] Multiply/Divide [Cancel out units]: $\displaystyle 127.61 \ g \ HCl$

<u>Step 4: Check</u>

<em>Follow sig fig rules and round. We are given 3 sig figs.</em>

127.61 g HCl ≈ 128 g HCl

3 0

3 years ago

A piece of wood burns to form ash. ____C_____ Water evaporates into steam. ____P_____ A piece of cork is cut in half. ____P_____

IceJOKER [234]

Answer:

A piece of wood burns to form ash - Chemical change

Water evaporates into steam - Physical change

A piece of cork is cut in half. __ Physical change

A bicycle chain rusts. _____Chemical change

Food is digested in the stomach. _____Chemical change

Water is absorbed by a paper towel. _____Physical change

Hydrochloric Acid reacts with zinc. _____Chemical change

A piece of an apple rots on the ground. ____Chemical change

A tire is inflated with air - Physical change

A Plant turns sunlight, CO2, and water into sugar and oxygen. _Chemical change

Sugar dissolves in water - Physical change

Eggs turn into an omelet. _____Chemical change

Milk sours. Chemical change

A popsicle melts. _____Physical change

Turning brownie mix into brownies. Chemical change

Explanation:

Matter undergoes two types of changes: physical changes and chemical changes.

A physical change is one that affects only the physical properties of a substance such as colour, size, shape, etc., and in which no new substances are formed. Physical changes are easily reversible.

Chemical changes are changes which affect the chemical characteristics and properties of a substance such as reactivity, acidity, basicity, etc., resulting in the formation of new substances.

The following changes below are categorized as either physical or chemical changes based on which of the properties of the substance is affected and whether new substances result or not.

A piece of wood burns to form ash - Chemical change

Water evaporates into steam - Physical change

A piece of cork is cut in half. __ Physical change

A bicycle chain rusts. _____Chemical change

Food is digested in the stomach. _____Chemical change

Water is absorbed by a paper towel. _____Physical change

Hydrochloric Acid reacts with zinc. _____Chemical change

A piece of an apple rots on the ground. ____Chemical change

A tire is inflated with air - Physical change

A Plant turns sunlight, CO2, and water into sugar and oxygen. _Chemical change

Sugar dissolves in water - Physical change

Eggs turn into an omelet. _ Chemical change

Milk sours - Chemical change

A popsicle melts. _____Physical change

Turning brownie mix into brownies - Chemical change

3 0

3 years ago

4. Which of the following NOT TRUE about real gas

Semenov [28]

Answer:

The answer is D.

Explanation:

Intermolecular force are negligible

When the distance between molecules decrease,

the attraction or repulsion become greater

7 0

2 years ago