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3 years ago

Substance is matter with a composition that is ?

Chemistry

1 answer:

STatiana [176]3 years ago

8 0

Answer:

A substance is a form of matter that will have a constant composition of evenly distributed products.

Explanation:

(Has to be the same everywhere)

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I begin the reaction with 0.45 g of beryllium. If my actual yield of beryllium chloride (mm = 79.91 g/mol) was 3.5 grams, what w

trasher [3.6K]

The percentage of yield was 777.78%

<u>Explanation:</u>

We have the equation,

Be [s] + 2 HCl [aq] → BeCl 2(aq] + H 2(g] ↑ Be (s] + 2 HCl [aq] → BeCl 2(aq] + H 2(g] ↑

To find the percent yield we have the formula

Percentage of Yield= what you actually get/ what you should theoretically get x 100

=3.5 g/0.45 g 100

= 777.78 %

The percentage of yield was 777.78%

5 0

3 years ago

Identify the neutral element represented by this excited-state electron configuration, then write the ground-state electron conf

sineoko [7]

Answer:

1s² 2s² 2p³

Nitrogen

Explanation:

Excited state configuration: 1s² 2s² 2p² 3s¹

Unknown:

Ground state configuration = ?

Element symbol = ?

Solution:

Let us start by understanding what a ground state configuration entails:

A ground state configuration shows the lowest allowed energy levels of an atom. The excited state denotes when electrons have moved to higher energy levels away from their ground state.

The superscript in the configuration depicts the number of electrons in each of the sublevels.

We can use this number to identify the atom we are dealing with:

Total number of electrons = 2 + 2 + 2 + 1 = 7 electrons

The element with 7 electrons on the periodic table is Nitrogen.

Now, the ground state configuration:

In writing the electronic configuration of an atom, certain rules must be complied with.

Aufbau's principle states that the sublevels with lower energies are filled up before those with higher energies. The order of filling is:

1s 2s 2p 3s 3p 4s etc

To fill the s-orbital = 2 electrons

p-orbital = 6 electrons

The outermost shell electrons are usually the ones excited.

Now, the 3s¹ shell is an excited one taking 1 electron from the second energy level;

The ground state configuration is 1s² 2s² 2p³

5 0

3 years ago

Balance the following equation Sa+ F2---> SF6

deff fn [24]

Answer:

s8 + 24f2 -> 8sf6

Explanation:

8 0

4 years ago

A chemist fills a reaction vessel with 9.20 atm nitrogen monoxide (NO) gas, 9.15 atm chlorine (CI) gas, and 7.70 atm nitrosyl ch

ivanzaharov [21]

Answer:

The reactions free energy $\Delta G = -49.36 kJ$

Explanation:

From the question we are told that

The pressure of (NO) is $P_{NO} = 9.20 \ atm$

The pressure of (Cl) gas is $P_{Cl} = 9.15 \ atm$

The pressure of nitrosly chloride (NOCl) is $P_{(NOCl)} = 7.70 \ atm$

The reaction is

$2NO_{(g)} + Cl_2 (g)$ ⇆ $2 NOCl_{(g)}$

From the reaction we can mathematically evaluate the $\Delta G^o$ (Standard state free energy ) as

$\Delta G^o = 2 \Delta G^o _{NOCl} - \Delta G^o _{Cl_2} - 2 \Delta G^o _{NO}$

The Standard state free energy for NO is constant with a value

$\Delta G^o _{NO} = 86.55 kJ/mol$

The Standard state free energy for $Cl_2$ is constant with a value

$\Delta G^o _{Cl_2} = 0kJ/mol$

The Standard state free energy for $NOCl$ is constant with a value

$\Delta G^o _{NOCl} =66.1kJ/mol$

Now substituting this into the equation

$\Delta G^o = 2 * 66.1 - 0 - 2 * 87.6$

$= -43 kJ/mol$

The pressure constant is evaluated as

$Q = \frac{Pressure \ of \ product }{ Pressure \ of \ reactant }$

Substituting values

$Q = \frac{(7.7)^2 }{(9.2)^2 (9.15) } = \frac{59.29}{774.456}$

$= 0.0765$

The free energy for this reaction is evaluated as

$\Delta G = \Delta G^o + RT ln Q$

Where R is gas constant with a value of $R = 8.314 J / K \cdot mol$

T is temperature in K with a given value of $T = 25+273 = 298 K$

Substituting value

$\Delta G = -43 *10^{3} + 8.314 *298 * ln [0.0765]$

$= -43-6.36$

$\Delta G = -49.36 kJ$

4 0

3 years ago

What is the name of the compound with the formula NaOH ?

vladimir2022 [97]

Answer:

Sodium hydroxide

Explanation:

Sodium hydroxide ( NaOH ) -

Sodium hydroxide is an inorganic compound , and is also called caustic soda and lye .

It is an ionic compound , which is white in color and is in solid state .

The cation and anion of this salt are the sodium cation Na⁺ and the hydroxide anions OH⁻ .

<u>It is highly basic in nature and is soluble in water , and when left open in air it can readily absorb moisture from the air , to form a hydrated sodium hydroxide .</u>

4 0

3 years ago