Which of the following groups of elements has two valence electrons and is highly reactive?

Select one:
a. Alkali metals
b. Alkaline-earth metals
c. Halogens
d. Noble gases

The percent yield : 73.5%

Given

Reaction

C+2H₂⇒CH₄

Required

The percent yield

Solution

mol of Carbon(as a limiting reactant) :

[tex]\tt \dfrac{100}{12}=8.3[/tex]

mol CH₄ based on C, and from equation mol ratio C : CH₄, so mol CH₄ = 8.3

Mass of Methane(theoretical yield) :

[tex]\tt mass=mol\times MW\\\\mass=8.3\times 16=133.3~g[/tex]

[tex]\tt \%~yield=\dfrac{actual}{theoretical}\times 100\%\\\\\%yield=\dfrac{98}{133.3}\times 100\%=73.5\%[/tex]

Actual yield : 45.752 g ⇒no option

Given

The theoretical yields of Cl₂ : 65.35 g and 68.08 g

Required

The actual yield

Solution

Reaction

4 HCl (aq) + MnO₂ (s) → MnCl₂ (aq) + Cl₂ (g) + 2H₂O (l)

Because there are two theoretical yields, then we can choose the smallest one because the value is usually determined from the limiting reactant (in this reaction the limiting reactant is MnO₂)

So 65.36 g is The theoretical yields of Cl₂

Then the actual yield :

[tex]\tt \%yield=\dfrac{actual}{theoretical}\times 100\%\\\\actual=\%yield\times theoretical\\\\actual=70\%\times 65.36=45.752[/tex]

Answer:

Elephant Toothpaste

Extra

Make Elephant Toothpaste

Pour 1/2 cup hydrogen peroxide solution, 1/4 cup dishwashing soap, and a few drops of food coloring into the bottle. Swish the bottle around to mix the ingredients. Set the bottle in a sink or outdoors or some other place where you won't mind getting wet foam everywhere.

In a separate container, mix a packet of active yeast with a little warm water. Give the yeast about five minutes to activate before proceeding to the next step.

When you are ready to do the demo, pour the yeast mixture into the bottle. The reaction occurs immediately upon the addition of the yeast.

I don't know if this will help but here you go.

the answer is electrons

Answer:

is there a picture.....????

Answer:

Trends on the Periodic Table have a vertical component and a horizontal component. Vertical trend: as more “shells” are added to the electron cloud, it expands. Horizontal trend: if atoms have the same number of “shells”, atoms with more protons will draw the electron cloud in tighter.

Explanation:

Answer:

Shear

Tension

Compression

Explanation:

The 3 stress forces are;

-shear

-tension

-compression

1) Shear is the stress force that pushes back a mass of rock in two opposite directions which in turn will produce strike - slip faults.

2) Tension is the stress force that pulls on the crust thereby stretching in a manner that it becomes thinner at its middle which in turn will produce normal faults.

3) Compression is the stress force that makes rocks squeeze until they fold or break and this will in turn produce reverse faults.

I can help with 1, 2, 3, and 4... 5 and 6, I don't understand.

Template sequence : TACCCTTGAATAAAAAATCTCTGTTTGGTCGGTATTGTTGAAATC

Complement sequence : ATGGGAACTTATTTTTTAGTGTCAAACCAGCCATAACAACTTTAG

mRNA sequence : AUGGGAACUUAUUUUUUAGAGACAAACCAGCCAUAACAACUUUAG

Anticodon sequence : AUG-GGA-ACU-UAU-UUU-UUA-GAG-ACA-AAC-CAG-CCA-UAA-CAA-CUU-UAG

(not 6) Protein synthesis : START-Gly-Thr-Tyr-Phe-Leu-Glu-Thr-Asn-Gin-Pro-Stop

Explanation:

kind of ion formed (anion or cation) and the size of the ionic charge. ... O-‐2 oxide. S-‐2 sulfide. N-‐3 nitride. P-‐3 phosphide. Table 3.1. Common, simple anions. It is critically important that you distinguish between ...

Ions and Ionic Compounds – Introductory Chemistry – 1st Canadian Edition - BC Open Textbooks

opentextbc.ca › chapter › ions-and-ionic-...

The formula Na 2Cl 2 also has balanced charges, but the convention is to use the lowest ratio of ions, which ... For the ionic compound between magnesium cations (Mg 2+) and oxide anions (O 2−), again we need only ...

[PDF] Tutorial 2 FORMULAS, PERCENTAGE COMPOSITION, AND THE MOLE FORMULAS: A chemical formula shows the elemental composition of a sub

www.eiu.edu › eiuchem › forms › t...

Ba2+ barium. HSO3. – hydrogen sulfite. MnO4. – permanganate. Al3+ aluminum. SO4. 2– sulfate. NO2. – nitrite. Sn2+ tin(II). HSO4. – hydrogen sulfate. NO3. – nitrate. Sn4+ tin(IV). S2O3. 2– thiosulfate. OH– hydroxide.

Symbols and Charges for Monoatomic Ions

www.edu.xunta.es › portal › Nomenclature

Cs+ cesium ion O2- oxide. Be2+ beryllium ion S2- sulfide. Mg2+ magnesium ion Se2- ... one K+ and one Cl¯ are required. The resulting formula is KCl. Example 3: Write the formula from the following name: barium

Barium chloride salts has a 3 to 2 ratio of cations to anions. thus option C is correct.

Barium Chloride an inorganic salt which is composed up of barium cations (Ba2+) and chloride anions (Cl–), otherwise named as  Barium Muriate or Barium dichloride.

It is a white solid , water-soluble, hygroscopic and gives a slight yellow-green color to a flame,  extensively used in the industry mainly The sulfate is used in white paints where as Barium chloride is poisonous in nature.

It is soluble in water which dissociate into barium cations and chloride anions in its dissolved state, However, the solubility of this compound in water is temperature-dependent.

For more details barium chloride,  visit

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Answer:

a substrate is surface or material on or from an organism lives, grows, or obtains its nourishment.

Explanation:

Hey I hope this helps.....

Answer:

is number 1

Explanation:

cause i know

The molarity = 0.04 M

The volume = 6.25 ml

Given

25cm³ of 0.1 M H₂SO₄

1.06g Na₂CO₃ in  250cm³ of solution

Required

the molarity and the volume of Na₂CO₃

Solution

Molarity of  Na₂CO₃ :

[tex]\tt \dfrac{1.06/106~mol}{0.25~L}=0.04~M[/tex]

Reaction

H₂SO₄ + Na₂CO₃ ⇒Na₂SO₄ + H₂O + CO₂

mol H₂SO₄ = 25 x 0.1 = 0.25 mlmol= 2.5 x 10⁻⁴ moles of  Na₂CO₃

The volume of solution used :

[tex]\tt V=\dfrac{n}{M}=\dfrac{2.5.10^{-4}}{0.04}=6.25.10^{-3}~L=6.25~ml[/tex]

Explanation:

mass H2O2 = 55 mL(1.407 g/mL) = 80.85 g

molar mass H2O2 = 2(1.01 g/mol) + 2(16.00 g/mol) = 34.02 g/mol

moles H2O2 = 80.85 g/34.02 g/mol = 2.377 moles H2O2

For each mole of H2O2 you obtain 0.5 mole of O2 (see the equation).

moles O2 = 2.377 moles H2O2 (1 mole O2)/(2 moles H2O2) = 1.188 moles O2

Now, you need the temperature.  If you are at STP (273 K, and 1.00 atm) then 1 mole of an ideal gas at STP has a volume of 22.4 L.  Without temperature you are not really able to continue.  I will assume you are at STP.

Volume O2 = 1.188 moles O2(22.4 L/mole) = 0.0530 L of O2.

which is  53 mL.

Answer:

3.06 m

Explanation:

Time of fall be t .

h = ut + 1/2 g t² , h is height , u is initial vertical velocity = 0

h = 1/2 g t²

32 = .5 x 9.8 x t²

t = 2.55 s

During this period , diver will move in horizontal direction also .

Horizontal displacement during fall

=  horizontal velocity x time

= 1.2 x 2.55

= 3.06 m  

Answer:

Bbbbb eg2020

Explanation:

Bbbbb

The correct answer is C. ΔHθf

We define the standard enthalpy of formation as the enthalpy change when one mole of a substance is formed from its elements under standard conditions. The standard conditions are 1 atm pressure, 273 K temperature and 1 M concentration.

The standard enthalpy of formation is denoted using the symbol ΔHθf.

Hence, ΔHθf is the enthalpy change when 1 mole of a substance is formed from its elements under standard conditions.

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Answer:

That's because the glass walls of the greenhouse trap the Sun's heat. The greenhouse effect works much the same way on Earth.

Explanation:

Gases in the atmosphere, such as carbon dioxide, trap heat just like the glass roof of a greenhouse. These heat-trapping gases are called greenhouse gases.

Answer:

1 oxygen from the lungs

Explanation:

maybe too help you breath better

Answer:

Each isotope of oxygen contains 8 protons, but differs in the number of neutrons. An isotope number is a shorthand representation of its mass. Because protons and neutrons are roughly equal in mass, an isotope's number is equal to the sum of its protons and neutrons.

Explanation:

Isotopes are atoms of the same element that have different numbers of neutrons but the same number of protons and electrons. The difference in the number of neutrons between the various isotopes of an element means that the various isotopes have different masses.

Answer:

See note in Explanation

Explanation:

The modern periodic table of the elements is arranged in order of increasing atomic numbers which is also in terms of the number of protons in the nucleus. That is, for any element listed on the periodic table its atomic number equals the number of protons in the nucleus. Thus, the element with 2 protons in its nucleus would be element #2 (Helium), element #3 (Lithium) has 3 protons in its nucleus and element #4 (Beryllium) has an atomic number 4 and contains 4 protons in its nucleus.

Also, this arrangement of elements finds that elements below elements 2, 3 & 4, Neon #10; sodium #11 & magnesium #12 have similar chemical and physical properties as does elements #2, #3 & #4. Such gives rise to the 'Periodic Law' => the chemical and physical properties of the elements is a periodic function of their atomic number (or, number of protons in the nucleus).

Answer:

A option

Explanation:

Because recatants are in solid form having less enetropy and products are liquid form having more entropy

While other options reactants and products are in same phase gas phase having same entropy

The reaction that would result in increased entropy is the combustion reaction;

KNO3(s)--->K+(aq)+NO3-(aq). Option A

This is further explained below

Generally, a combustion reaction is simply a combustion process that occurs when a material combines with oxygen gas, producing energy as light and heat.

In conclusion, the chemical reaction KNO3(s)--->K+(aq)+NO3-(aq) is has all properties of a combustion reaction as the solid reactants gives an aq solution.

Read more about Chemical reaction

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Answer:

Solvent

Explanation:

When one substance dissolves into another, a solution is formed. A solution is a homogeneous mixture consisting of a solute dissolved into a solvent

Answer:

true

Explanation: all matter down to the molecular or even atomic level has a constant vibration and movement. The only time that any matter could stop moving would be at absolute zero.

Answer:

c warm water

Explanation:

Kinetic energy is related to temperature. The molecules in a glass of warm water have more kinetic energy (they move faster – see Racing Molecules) than the molecules in a glass of cold water. The temperature of a substance is the average* amount of kinetic energy its molecules have.

Answer:

hot water

Explanation:

Answer:

You can find the mass of water by multiplying the density of water by its volume.

mass = Density x volume

Explanation:

It is very easy to find the mass of water once you know the formula of density. "Density" refers to mass per unit volume.

Density (ρ) = [tex]\frac{mass}{volume}[/tex]

Therefore, mass = ρ x volume

The density of water is 1 kg/L.

For example, if the volume of water is 500 ml, then you can get its mass by multiplying 500 ml by 1 kg/L.

Let's convert 500 ml to Liter first.

500 ml x [tex]\frac{1 L}{1,000 ml}[/tex] = 0.5 L

Now, let's compute.

mass = ρ x volume

mass = 1 kg/L x 0.5L

mass = 0.5 kg

The mass of a 500-ml water is 0.5 kg.

Answer:

The circulatory and respiratory systems work together to circulate blood and oxygen throughout the body. Air moves in and out of the lungs through the trachea, bronchi, and bronchioles. Blood moves in and out of the lungs through the pulmonary arteries and veins that connect to the heart

Explanation:

This should help you out

Answer:

See explanation

Explanation:

Dalton's atomic theory furnished us with a basis to discuss the theory of atoms. However, not all his ideas holds up under the scruitiny of morden science.

He postulated that atoms were 'indivisible' the discovery of subatomic particles indeed show that there are smaller particles than atoms.

His postulation that atoms can neither be created nor destroyed does not hold water today because atoms are being created in nuclear reactors.

He said that atoms of all elements are exactly alike. Today we know there are isotopes of elements which are not exactly alike.

We can see that the Dalton's atomic theory did not take cognisance of the important role of subatomic particles in studying the structure of the atom. Modern atomic theory tries to look at the importance of these particles in the understanding the structure of the atom.

Answer:

OB- one or more cells

Explanation:

hope this helps :)

Answer:

37.85 liters

Explanation:

they need 10 gallons for a month (2.5*4)

after that, convert gallons to liters (conversion to liters= 3.785)

10*3.7585= 37.85