can someone explain this to me?​

Answer:

The correct option is;

By first reversing Reaction 2 and then adding the enthalpy of Reaction 1 and the enthalpy of reaction 2

Explanation:

The given reactions are;

1) C₂H₂ (g) +  2H₂ (g)  → C₂H₆ (g)     [tex]{}[/tex]      ΔH = -75 kcal

2) C₂H₄ (g) +  H₂ (g)  → C₂H₆ (g)     [tex]{}[/tex]      ΔH = -33 kcal

3) C₂H₂ (g) +  H₂ (g)  → C₂H₄ (g)     [tex]{}[/tex]      ΔH = ?

By reversing reaction (2) and subtracting the reactants from the products we then have followed by adding the enthalpy of reaction 1 to the value of the enthalpy of the (reversed) reaction 2, we have;

C₂H₂ (g) + 2H₂ (g)  → C₂H₆ (g)     [tex]{}[/tex]      ΔH = -75 kcal

C₂H₆ (g) → C₂H₄ (g) + H₂ (g)       [tex]{}[/tex]       ΔH = 33kcal

Adding, and cancelling out the italicized terms which are repeated in the product and reactants, we get

C₂H₂ (g) + H₂ (g) → C₂H₄ (g)       [tex]{}[/tex]   ΔH = -75 kcal + 33 kcal = -42 kcal

Therefore, the correct option is "by first reversing Reaction 2 and then adding the enthalpy of Reaction 1 and the enthalpy of reaction 2"

Answer: The ionic formula of compound is [tex]CoP[/tex] and the name is cobalt phosphide.

Explanation:

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.

Here element Co is having an oxidation state of +3 called as [tex]Co^{3+}[/tex] cation and phosphprous forms [tex]P^{3-}[/tex] anion with oxidation state of -3. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral [tex]CoP[/tex]

The nomenclature of ionic compounds is given by:

1. Positive is written first followed by the oxidation state of metal in roman numerals in square brackets.

2. The negative ion is written next and a suffix is added at the end of the negative ion. The suffix written is '-ide'.

Thus the name of [tex]CoP[/tex] is cobalt phosphide.

Answer: A

Explanation: TOOK THE QUIZ !))   200 YEARS AGOO

Answer:

The correct answer is -

1. 1 grain of sand = 244 red blood cells.

2. 1 penny = 2439

Explanation:

A normal red blood cell has a normal disk diameter of 6.2 - 8.2 micron or micrometer is way small than a grain of sand which ranges in diameter from 0.0625 mm (or ​1⁄16 mm) to 2 mm. The size of the diameter of a penny is given 0.02 m.

Let take the highest value of them:

RBC = 8.2 micrometer

The grain of sand = 2 mm

Penny = 0.02 m

we know:

1 meter = 10e+6 or 100000 micron

1 millimeter = 1000 micron

then, the grain of sand = 2* 1000 = 2000

so, the 1 grain sand = 2000/8.2

= 244

Similarly,

Penny = 0.02*100000= 20000

= 2439

Thus, the correct answer is =

1. 1 grain of sand = 244 red blood cells.

2. 1 penny = 2439

Natural selection cannot work if beneficial traits are not hereditary

Answer:

favors organisms well adapted to the environment

cannot work if beneficial traits are not hereditary

is often called survival of the fittest

Explanation:

NOT

is random

happens by chance

Answer:

Mixing bleach and ammonia will create a toxic chloramine gas. Exposure to chloramine gas can cause irritation to your eyes, nose, throat, and lungs .

if you do accidentally mix bleach and ammonia, get out of the contaminated area and into fresh air immediately.

hope this help u ☆

Answer:

It's polar

Explanation:

Hydrogen has an EN of 2.1 and Fluorine an EN of 4.0 (highest EN of any element). So do:  4.0−2.1=1.9.

Answer:

It also contains other gases, including carbon dioxide and helium, and various pollutants (both gases and solids).

answer: c

because if you really picture it and look at each of  them carefully it is c

Answer:

El mismo nivel, pero diferente subnivel y orbital

Explanation:

En un átomo, el número cuántico principal n muestra el nivel de energía del electrón.

Si dos electrones tienen el mismo valor del número cuántico principal n, simplemente significa que están en el mismo nivel de energía.

Sin embargo, cuando los números cuánticos l y ml difieren, los electrones deben estar en diferentes subniveles y orbitales.

Answer: W

Explanation:

The cell in liquid W will look the smallest out of the four because of Osmosis.

Osmosis is a process by which water molecules move from an area of relatively higher concentration of water to an area with a relatively lower concentration through a selectively permeable membrane(cell membrane).

With W being saltier than the cell, water molecules will move from the cell to liquid W to balance the concentrations inside and outside the cell which will lead to the cell in W being smaller.

Answer:

Option C

Explanation:

A) A chemical equation is simply the symbolic representation of a chemical reaction using the form of symbols and formulae. Thus, option A is not the answer.

B) A product is the substance that shows at the end of a chemical reaction. Thus, option B is not the answer.

C) Law of conservation of mass in chemistry states that even in chemical reactions or physical transformations, that mass cannot be created nor destroyed. Which means that mass is conserved. This has nothing to do with chemical change demonstrated chemical reactions. Thus, option C is correct.

D) reaction rate is the speed that a chemical reaction occurs. Thus, options D is not correct.

Answer:

c.all atoms have the same arrangement for electrons

Answer:

C because the number of protons and neutrons add up to make the number of electrons.

Answer:

0.0917 mol Co(CrO₄)₃

General Formulas and Concepts:

Chemistry - Atomic Structure

Explanation:

Step 1: Define

37.3 g Co(CrO₄)₃

Step 2: Identify Conversions

Molar Mass of Co - 58.93 g/mol

Molar Mass of Cr - 52.00 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of Co(CrO₄)₃ - 58.93 + 3(52.00) + 12(16.00) = 406.93 g/mol

Step 3: Convert

[tex]37.3 \ g \ Co(CrO_4)_3(\frac{1 \ mol \ Co(CrO_4)_3}{406.93 \ g \ Co(CrO_4)_3} )[/tex] = 0.091662 mol Co(CrO₄)₃

Step 4: Check

We are given 3 sig figs. Follow sig fig rules and round.

0.091662 mol Co(CrO₄)₃ ≈ 0.0917 mol Co(CrO₄)₃

Answer:

....? What-

Explanation:

Answer:

1/6 of your weight on Earth

Answer:

the amount of the force of gravity changes

Answer:

A all organisms are made of 1 or more cells

Answer:

196.96655

Explanation:

The answer is 196.96655. I assume you are converting between grams Gold and mole. The molecular formula for Gold is Au. The SI base unit for the amount of substance is the mole.

The quantity present in an atom or molecules of a given substance is called moles it is written as mol and is calculated with the help of molar mass and mass of the given substance.

0.507699 mol is present in the 100 gm of gold.

Given,

The formula for calculating moles is:

[tex]\rm Moles (n) = \dfrac{Mass}{Molar \;mass}[/tex]

Substituting values in the formula:

[tex]\begin{aligned}\rm n & = \dfrac{100}{196.967}\\\\ & = 0.507699 \;\rm mol\\\\& = 0.5077\;\rm mol\end{aligned}[/tex]

Therefore, 0.5077 mol is present in 100 gm of gold.

Learn more about moles here:

https://brainly.com/question/6260819

Answer:

B! i just learned this last week lol!

Explanation:

hope this helps♡♡

Answer:

oxygen is an example of a diatomic molecule found in earth's atmosphere!

Explanation:

Answer:B

Explanation:

Had the same test years ago

The salt in ocean water comes from various sources such as the volcanic emissions, land eruption, ionic reactions in sea floor etc. but not from the melting of glacial ice.

Salt in ocean water is the ionic compound NaCl that we are using as the table salt to add in foods. The Na+ and Cl- ions are reaching to the ocean through various geographical process.

One of them is volcanic eruptions by in the tectonic plate boundaries. Volcanoes containing sulfur and chlorine atoms which are falling to the ocean. Similarly  land eruption also result in salt formation in oceans.

Land rocks contains minerals such as limestone, epsom salt, and table salt. Weathering process break down these minerals and dissolve in water. Melting of glacial ice increases the water level but does not make water salty.

To find more on weathering, refer here:

https://brainly.com/question/14426457

#SPJ5

Answer:

I believe it's ... North Africa and the Italian Peninsula

Answer:

try a calulator online just go to g.oogle and type in gpa calculator

Answer:

It is called ions

Explanation:

Metal atoms lose some of their valence electrons through a process called oxidation, resulting in a large variety of ionic compounds including salts, sulfides, and oxides. The properties of metals, combined with the chemical action of other elements, results in the transfer of electrons from one atom to another.

Answer:

its called an ion

Explanation:

an ion is an electrically charged atom

Answer:

d

Explanation:

moles Cl⁻ : 0.00197

mass NaCl : 0.115

% purity : 95.83%

Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution

[tex]\large \boxed {\bold {M ~ = ~ \dfrac {n} {V}}}[/tex]

Where

M = Molarity

n = Number of moles of solute

V = Volume of solution

So to find the number of moles can be expressed as

n = V x M

Reaction

AgNO₃ + NaCl ⇒ AgCl + NaNO₃

Molarity(concentration) of AgNO₃ = 0.1 mol/dm³(L) = 0.1 M

Volume=V of AgNO₃ = 19.7 ml(cm³)

so mol of AgNO₃ :

[tex]\tt mol=M\times V\\\\mol=0.1~mol/L\times 0.0197~L\\\\mol=0.00197[/tex].

From the equation, mol ratio AgNO₃ : NaCl  = 1 ; 1, so mol NaCl= mol AgNO₃= 0.00197

NaCl⇒Na⁺+Cl⁻

mol Cl⁻ : mol NaCl = 1 : 1, mol Cl⁻ = 0.00197

[tex]\tt mass=mol\times MW\\\\mass= 0.00197\times 58.5=0.115~g[/tex]

[tex]\tt \%purity=\dfrac{mass~NaCl}{mass~rock}\times 100\%\\\\\%purity=\dfrac{0.115}{0.12}\times 100\%=95.83\%[/tex]

Answer:

Explanation:Due to the mental pressure,

                       Due to peer pressure,

                      Lack of love and affection from the family members.

                      Influence from the T.V advertisement.

Answer:

C₂H₆

Explanation:

Here,

The Empirical Formula is CH₃

Now, 2 × CH₃ = C₂H₆

Thus, The Molecular Formula of CH₃ is C₂H₆

-TheUnknownScientist

Answer:

negative charge

Explanation:

An anion has more electrons than protons, consequently giving it a net negative charge.

hope this helps, pls mark brainliest :D

Explanation:

Lustrous (shiny)

Good conductors of heat and electricity.

High melting point.

High density (heavy for their size)

Malleable (can be hammered)

Ductile (can be drawn into wires)

Usually solid at room temperature (an exception is mercury)

Opaque as a thin sheet (can't see through metals)

Answer:

The answer is B.xd

Explanation:

Answer:

Ciao Adios by Anna-Marie

Explanation:

ooof I like that song