How can carbon dating be used to study the history of the earth?

Answer:

When fossil fuels are burned carbon and hydrogen react with oxygen in air to carbon dioxide (CO2) and water (H2O). During this reaction heat is released which further amplifies the reaction. Electricity is generated by transforming mechanical energy (heat) to electrical energy in a turbine or generator.

Explanation:

Answer:

divergent boundaries- volcanic activity, shallow earthquakes, new sea floor.

convergent boundaries- earthquakes, volcanoes, formation of mountains.

transform boundaries- earthquakes, crustal deformation

Explanation:

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Answer:

It would produce ethane (CH₃CH₃)

Explanation:

Ethylmagnesium bromide (CH₃CH₂MgBr) is a Grignard's reagent.

It is a highly reactive substance, and as any alkylmagnesium bromide

(R-CH₂MgBr) it reacts with water to produce an alkane (R-CH₃). R stands for any carbon structure bonded to that functional group.

Answer:

SO₄²⁻(aq) + Ba²⁺(aq) ⇒ BaSO₄(s)

Explanation:

Let's consider the molecular equation that occurs when aqueous solutions of ammonium sulfate and barium nitrate are mixed.

(NH₄)₂SO₄(aq) + Ba(NO₃)₂(aq) ⇒ BaSO₄(s) + 2 NH₄NO₃(aq)

The complete ionic equation includes all the ions and insoluble species.

2 NH₄⁺(aq) + SO₄²⁻(aq) + Ba²⁺(aq) + 2 NO₃⁻(aq) ⇒ BaSO₄(s) + 2 NH₄⁺(aq) + 2 NO₃⁻(aq)

The net ionic equation includes only the ions that participate in the reaction and the insoluble species.

SO₄²⁻(aq) + Ba²⁺(aq) ⇒ BaSO₄(s)

Answer:

True

True

Temperature

Explanation:

The molecular formula : C₄H₈O₂

Maybe a compound is 54.5% carbon, 9.1% hydrogen and 36.4% oxygen,so :

mol C :

[tex]\tt \dfrac{54.5}{12}=4.54[/tex]

mol H :

[tex]\tt \dfrac{9.1}{1}=9.1[/tex]

mol O :

[tex]\tt \dfrac{36.4}{16}=2.28[/tex]

Divide by 2.28(the smallest ratio) :

C H : O =

[tex]\tt \dfrac{4.54}{2.28}\div \dfrac{9.1}{2.28}\div \dfrac{2.28}{2.28}=2\div 4\div 1[/tex]

The empirical formula : C₂H₄O

(The empirical formula)n=molecular formula

(2.12+4.1+16)n=88

(44)n=88⇒n=2

The molar mass of gas = 206.36 g/mol

In general, the gas equation can be written

[tex]\large{\boxed{\bold{PV=nRT}}}[/tex]

where

P = pressure, atm

V = volume, liter

n = number of moles

R = gas constant = 0.082 l.atm / mol K

T = temperature, Kelvin

mass (m)= 2.89 g

volume(V) = 346 ml = 0.346 L

T = 28.3 C + 273 = 301.3 K

P = 760 mmHg=1 atm

The molar mass (M) :

[tex]\tt PV=\dfrac{m}{M}RT\\\\M=\dfrac{mRT}{PV}\\\\M=\dfrac{2.89\times 0.082\times 301.3}{1\times 0.346}\\\\M=206.36~g/mol[/tex]

Answer:

30 g/mol

Explanation:

Step 1: Given data

Step 2: Calculate the moles corresponding to 11.2 L of gas

At normal temperature and pressure (1 atm, 293.15 K), 1 mol of a gas has a volume of 24.05 L.

11.2 L × 1 mol/24.05 L = 0.466 mol

Step 3: Calculate the molecular mass of the gas

0.466 moles of the gas weigh 14 g. The molecular mass is:

M = 14 g/0.466 mol = 30 g/mol

Answer:bromine , neon , helium , argon , lithium , beryllium

Explanation:

Elements can be divided into three state that are solid, liquid and gas depending the intermolecular forces of attraction, distance between the particles etc. Lithium, beryllium, boron, carbon, sodium, magnesium, iron, copper, etc. are solid at room temperature.

Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.

Two or more than two atoms with different physical or chemical properties can not combine together to form an element. Elements can be solid liquid or gas at room temperature.

Therefore,  Lithium, beryllium, boron, carbon, sodium, magnesium, iron, copper, etc. are solid at room temperature.

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Answer:

True

Explanation:

Answer:

pH = 7.49

Explanation:

This is a buffer solution. We can apply Henderson Hasselbach equation:

pH = pKa + log ((total mmoles - mmoles HCl) / mmoles HCl)

We have the same amount of mmoles.

35 mL . 0.400 M = 14 mmoles HCl

35 mL . 0.400 M = 14 mmoles NaClO

Total moles are 28 mmoles.

We replace data:

pH = pKa + log ((28 mmoles -14 mmoles) / 14 mmoles)

Notice that the relation in log = 1. So pH = pKa

pKa for HClO is 7.49

When pH = pKa we have the same amount of base and acid. Notice, that we have the same mmoles of HCl and NaClO.

Remember that a buffer can be prepared with:

a) A weak acid and its conjugate base (acetic /acetate)

A weak base and its conjugate acid (ammonia/ammonium)

b) A weak acid with a strong base, where the acid can be in excess.

c) A conjugate base (salt from weak acid) with a strong acid, where the base can be in excess. (This case but, the base is not in excess, that's why ph = pKa)

Answer:

yes that is true........

The final temperature of the mixture : 21.1° C  

The law of conservation of energy can be applied to heat changes, i.e. the heat received / absorbed is the same as the heat released  

Q in(gained) = Q out(lost)  

Heat can be calculated using the formula:  

Q = mc∆T  

Q = heat, J  

m = mass, g  

c = specific heat, joules / g ° C  

∆T = temperature difference, ° C / K  

Q ethanol=Q water

mass ethanol=

[tex]\tt mass=\rho\times V\\\\mass=0.789\times 45=35.505~g[/tex]

mass water =

[tex]\tt mass=1~g/ml\times 45~ml=45~g[/tex]

then the heat transfer :

[tex]\tt 35.505\times 2.42~J/g^oC\times (t-6)=45\times 4.18~J/g^oC\times (28-t)\\\\85.922t-515.533=5266.8-188.1t\\\\274.022t=5782.33\rightarrow t=21.1^oC[/tex]

Answer:

CuSO4 + 2NH4OH -----> Cu(OH)2 + (NH4)2SO4

Explanation:

Explanation:

Cellulose fibers, structural proteins, and other polysaccharides help to maintain the shape and form of the cell. Additional functions of the cell wall include: Support: The cell wall provides mechanical strength and support. It also controls the direction of cell growth.

Answer:

ATP is a stored form of energy

Explanation:

it is the main source of this

Answer:

ZnCl2

H2

Explanation:

The products of the given reaction is:

      ZnCl₂  and H₂

The two species are the products of the chemical combination

Answer:

bent

Explanation:

The chlorite ion has been pictured in the image attached with its two main resonance contributors.

The ion has four regions of electron density as shown. On the basis of the VSEPR theory, we expect a tetrahedral geometry.

However, the ion is bent due to the effect of the lone pairs on chlorine which is the central atom in the ion. This distorts the bond angle of the ion hence the ion has a bent molecular geometry.

Answer:

23.1 x 10^11

Explanation:

(4.2x5.5) x (10^9x10^2)

23.1 x 10^11   (Add the exponents, and multiply the decimals.)

I hope this helped! :)

Answer:The  standard cell potential, E˚cell =2.234 V, Pb metal is the cathode.

Explanation:

The Half cell reactions are

Pb2+(aq) + 2e– > Pb(s) ------E˚ = –0.136 V

Mg2+(aq) + 2e–>Mg(s)------- E˚ = –2.37 V

In a voltaic cell, reduction occurs at the cathode and oxidation occurs at the anode

 Mg(s)---->Mg2+(aq) + 2e–  ( anodic oxidation)

   Pb2+(aq) + 2e---->  Pb(s)  ( Cathodic reduction)

We can see that Mg  has a more negative reduction potential value leading to having a low reduction potential and therefore will occur at the anode since it will be oxidized. On the other hand Pb2+ has a less negative reduction potential and therefore will have a high reduction making it to occur at the cathode and be reduced

Using  The  standard cell potential, E˚cell = E˚cathode – E˚anode

E˚cell = –0.136 - (–2.37)

E˚cell=2.234 V

Answer:

The mass of ammonia (NH3) that contains [tex]1.00 \times 10^12[/tex] hydrogen atoms is [tex]9.4\times 10^{-12}[/tex] g.

Explanation:

As [tex]6.022\times 10^{23}[/tex] atoms of hydrogen = 1 mole of the hydrogen atom

Therefore, [tex]10^{12}[/tex] atoms of hydrogen [tex]= \frac{1}{6.022 \times 10^{23}}\times 10^{12}=1.66\times 10^{-12}[/tex] moles of the hydrogen atom.

Now, there are 3 moles of hydrogen atoms in 1 mole of ammonia [tex](NH_3)[/tex].

As the mass of 1 mole of ammonia is 17g, so

when there are 3 moles of hydrogen atoms, then the mass of ammonia = 17 g

Therefore, when there are [tex]1.66\times 10^{-12}[/tex] moles of hydrogen atoms, then the mass of ammonia [tex]= \frac{17}{3}\times 1.66\times 10^{-12}=9.4\times 10^{-12[/tex] g.

Hence, the mass of ammonia [tex](NH_3)[/tex] that contains [tex]1.00 \times 10^12[/tex] hydrogen atoms is [tex]9.4\times 10^{-12}[/tex] g.

Answer:

1. mol/L

2. 0.120 M

Explanation:

1. Molarity is equal to the moles of solute divided by the liters of solution. The units of molarity are mol/L.

2.

Step 1: Given data

Step 2: Calculate the moles of solute (n)

The molar mass of NaCl is 58.44 g/mol.

n = 5.25 g × 1 mol/58.44 g = 0.0898 mol

Step 3: Determine the molarity of the solution

We will use the definition of molarity

M = n/V

M = 0.0898 mol / 0.7500 L = 0.120 M

Answer:

Thermal energy (also called heat energy) is produced when a rise in temperature causes atoms and molecules to move faster and collide with each other. The energy that comes from the temperature of the heated substance is called thermal energy.

Explanation:

will this help you

Answer:

A chemical change has occurred

Explanation:

Given reaction expression:

      CaCO₃ →  CaO  +  CO₂

The reaction is a decomposition reaction in which a compound is dissociated into simple products.

The reason why the products have different properties than the reactants is because a chemical change has occurred.

The products of the decomposition of calcium carbonate have different properties because a chemical change has occured in the reaction to form new substances.

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Answer:

One atom of that element like helium neon and other Noble gases

Explanation:

Answer:

Explanation:

The number of protons in the nucleus of an atom determines an element's atomic number. In other words, each element has a unique number that identifies how many protons are in one atom of that element. An example is all hydrogen atoms, and only hydrogen atoms, contain one proton and have an atomic number of 1.

Answer:

0.49 mol HCl

General Formulas and Concepts:

Chemistry - Atomic Structure

Explanation:

Step 1: Define

18 g HCl

Step 2: Identify Conversions

Molar Mass of H - 1.01 g/mol

Molar Mass of Cl - 35.45 g/mol

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

Step 3: Convert

[tex]18 \ g \ HCl(\frac{1 \ mol \ HCl}{36.46 \ g \ HCl} )[/tex] = 0.493692 mol HCl

Step 4: Check

Round our answer to 2 decimal places.

0.493692 mol HCl ≈ 0.49 mol HCl

Answer:

0.49 mol

Explanation:

Answer:

The answer is "Option b".

Explanation:

[tex]\to \text{number of moles} = \frac{\text{number of atoms}}{\text{avogadro number}}[/tex]

                               [tex]= \frac{7.0 \times 10^{19}}{6.0221 \times 10^{23}}\\\\= 1.16 \times 10^{-4} \ moles\\\\ =1.2 \times 10^{-4} \ moles[/tex]

[tex]\to \text{sample mass}= \text{number of moles} \times \text{molar mass}[/tex]

                        [tex]=1.16 \times 10^{-4}\times 58.9\\\\=0.00685 \\\\ = 6.85\ g[/tex]