The elements of the group IA are termed as alkali metals, because their ___ are alkaline.

Answer:

212 000 yrs

Explanation:

15/16 decay means 1/16 is left

 how many halflives is this?

                    (1/2)^n = 1/16

                       n = 4   half lives

4 half lives * 53 000 yr/ half life = 212 000 yrs

Answer:

c. 212,000 years

Explanation:

got it right on edge:3

Answer: No of molecule of sucrose = 1.806 X 10^24

Explanation:

No. of molecules = No. of moles X NA

No. of molecule of sucrose = 3 moles X 6.02 X 10^23

No of molecule of sucrose =18.06 X 10^23

No of molecule of sucrose =1.806 X 10^24

Answer:

1.80 × 10²⁴ Molecules of Sucrose

1a. The empirical formula of the compound is Fe₂O₃

1b. The molecular formula of the compound is Fe₂O₃

2a. The molecular formula of the anhydrous salt is MgSO₄

2b. The formula of the crystalline salt is MgSO₄.7H₂O

3i. The number of mole of carbon atoms in the compound is 6 moles

3ii. The number of mole of hydrogen atoms in the compound is 18 moles

3iii. The number of molecules in 3 moles of ethane is 1.806×10²⁴ molecules

Divide by their molar mass

Fe = 69.9 / 56 = 1.248

O = 30 / 16 = 1.875

Divide by the smallest

Fe = 1.248 / 1.248 = 1

O = 1.875 / 1.248 = 3/2

Multiply by 2 to express in whole number

Fe = 1 × 2 = 2

O = 3/2 × 2 = 3

Thus, the empirical formula of the compound is Fe₂O₃

Molecular formula = empirical × n = molar mass

[Fe₂O₃]n = 159.89

[(56×2) + (16×3)]n = 159.89

160n = 159.89

n = 159.89 / 160

n = 1

Molecular formula = [Fe₂O₃]n

Molecular formula = [Fe₂O₃] × 1

Molecular formula = Fe₂O₃

We'll begin by calculating the empirical formula

Divide by their molar mass

Mg = 20.0 / 24 = 0.83

S = 26.66 / 32 = 0.83

O = 53.33 / 16 = 3.33

Divide by the smallest

Mg = 0.83 / 0.83 = 1

S = 0.83 / 0.83 = 1

O = 3.33 / 0.83 = 4

Thus, the empirical formula of the anhydrous salt is MgSO₄

The molecular formula of the anhydrous salt can be obtained as follow:

Molecular formula = empirical × n = molar mass

[MgSO₄]n = 120

[24 + 32 + (16×4)]n = 159.89

120n = 120

n = 120 / 120

n = 1

Molecular formula = [MgSO₄]n

Molecular formula = [MgSO₄] × 1

Molecular formula = MgSO₄

Divide by their molar mass

MgSO₄ = 48.8 / 120 = 0.4

H₂O = 51.2 / 18 = 2.8

Divide by the smallest

MgSO₄ = 0.4 / 0.4 = 1

H₂O = 2.8 / 0.4 = 7

Thus, the formula of the crystalline salt is MgSO₄.7H₂O

1 mole of C₂H₆ contains 2 moles of carbon atoms.

Therefore,

3 moles of C₂H₆ will contain = 3 × 2 = 6 moles of carbon atoms

1 mole of C₂H₆ contains 6 moles of hydrogen atoms.

Therefore,

3 moles of C₂H₆ will contain = 3 × 6 = 18 moles of hydrogen atoms

From Avogadro's hypothesis,

1 mole of ethane = 6.02×10²³ molecules

Therefore,

3 moles of ethane = 3 × 6.02×10²³ molecules

3 moles of ethane = 1.806×10²⁴ molecules

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Complete question

2. A crystalline salt when heated becomes anhydrous and loses 51.2% of its weight the anhydrous salt analysis gave the percent composition as magnesium is equal to 20.0% and sulphur is equal to 26.66% and oxygen is equal to 53.33%. Ccalculate the molecular formula of the anhydrous and the crystalline salt. The molecular weight of the anhydrous salt is 120

The value of ΔS° for reaction  is - 22.2 J/K.mol

[tex]SO_{2}(s)+NO_{2} (g)[/tex] → [tex]SO_{3}(g)+NO(g)[/tex]

Calculation,

Given value of S°(J/K.mol) for

[tex]SO_{2}(s)[/tex] = 248.5

[tex]NO_{2} (g)[/tex] = 240.5

[tex]NO(g)[/tex] = 210.6

[tex]SO_{3}(g)[/tex] = 256.2

Formula used:

ΔS° (Reaction) =  ∑S°(Product) - ∑S°(Reactant)

ΔS° = (256.2 + 210.6 ) - ( 248.5 + 240.5) = 466.8 - 489 = - 22.2 J/K.mol

The change in stander entropy of reaction is  - 22.2 J/K.mol. The negative sign indicates the that entropy of reaction is decreases when reactant converted into product.

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Answer:

[tex]K2O[/tex]

Explanation:

If you use a melting point periodic table there is a listing of all the elements and their melting point.

Potassium (K) has a melting point of 63.25 degrees Celsius and oxygen (O) has a melting point of -218 degrees Celsius. Therefore, if you add those two values up

[tex](63.25x2)+-218 = -91.5 Degrees Celsius[/tex]

All the other compounds do not reach negatives.

Answer:

Ethylene oxide

Explanation:

Ethylene oxide is an organic compound with the formula C2H4O. It is a cyclic either and the simplest epoxied: a three-membraned ring consisting of one oxygen atom and two carbon atoms!

Correct answer:

The relative humidity is best described as the amount of water vapor in the air at a given temperature expressed as a percentage of the water vapor capacity of the air.

What is relative humidity?

The ratio of the current absolute humidity to the highest absolute humidity is known as relative humidity (which depends on the current air temperature).

Water vapor is also measured by relative humidity, which is stated as a percentage but RELATIVE to the air's temperature. In other words, it is a comparison between the amount of water vapor that is actually present in the air and the maximum amount of vapor that is possible for the air at the current temperature.

With the same quantity of absolute/specific humidity, air will have a HIGHER relative humidity if it is cooler and a LOWER relative humidity if it is warmer because warm air may contain more water vapor (moisture) than cold air. The actual amount of moisture (absolute humidity) in the air is what we "feel" outside.

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Answer:

d. oligomer it is the correct answer also if you would just search that up it pops up

When 3-methyl-2-butanone undergoes a baeyer-villiger oxidation reaction, the product is isopropyl acetate and methyl isobutyrate.

The Baeyer-villiger oxidation would seem to be a chemical reaction that uses peroxy acids using peroxides as the oxidant to transform a ketone into an ester or a lactone from such a cyclic ketone.

The main product produced by the Baeyer-Villiger oxidation of camphor using m-CPBA in buffer conditions could be created as a result of the migration of a tertiary bridgehead carbon as opposed to a methylene group.

By the reaction between 3-methyl-2-butanone with m-CPBA , will form isopropyl acetate and methyl isobutyrate.

It reaction can be shown as:

Therefore, when 3-methyl-2-butanone undergoes a Baeyer-villiger oxidation reaction, the product is isopropyl acetate and methyl isobutyrate.

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Answer:

k ion is the largest size of the radius it is always smaller compared to the parent ion

Explanation:

Answer:

3 NO₂ (g) + H₂O (l) ---> 2 HNO₃ (aq) + NO (g)

Explanation:

Gaseous nitrogen dioxide = NO₂ (g)

Liquid water = H₂O (l)

Because the reactants are dissolved = HNO₃ (aq)

Gaseous nitrogen monoxide = NO (g)

In order for a reaction to be balanced, there needs to be an equal amount of each type of atom on both sides of the equation. The equation can be balanced by adding coefficients to modify the quantities of certain compounds.

The unbalanced equation:

NO₂ (g) + H₂O (l) ---> HNO₃ (aq) + NO (g)

Reactants: 1 nitrogen, 3 oxygen, 2 hydrogen

Products: 2 nitrogen, 4 oxygen, 1 hydrogen

The balanced equation:

3 NO₂ (g) + H₂O (l) ---> 2 HNO₃ (aq) + NO (g)

Reactants: 3 nitrogen, 7 oxygen, 2 hydrogen

Products: 3 nitrogen, 7 oxygen, 2 hydrogen

18 g of silicon-32 will be present in 800 years.

A radioactive half-life refers to the amount of time it takes for half of the original isotope to decay and it's given by

                              [tex]N(t) = N_0 (\frac{1}{2}) ^\frac{t}{t_\frac{1}{2} }[/tex]

where,

[tex]N(t) =[/tex] quantity of the substance remaining

[tex]N_0 =[/tex]  the initial quantity of the substance

[tex]t =[/tex]  time elapsed

[tex]t_1_/_2 =[/tex] the half-life of the substance

From the given information we know:

The initial quantity of silicon-32 is 40 g.

The time elapsed is 800 years.

The half-life of silicone-32 is 710 years.

So, using the calculation above, we can determine how much silicon-32 is left.

                  [tex]N(t) = 40 (\frac{1}{2}) ^\frac{800}{710} \\N(t) = 40 (\frac{1}{2}) ^\frac{80}{71} \\\\N(t) = 18 g[/tex]

Therefore,18 g of silicon-32 will be present in 800 years.

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Answer:

1.81 x 10²² atoms O

Explanation:

To find the number of oxygen atoms, you need to (1) convert grams CaCO₃ to moles CaCO₃ (via molar mass), then (2) convert moles CaCO₃ to moles O (via mole-to-mole ratio from formula subscripts), and then (3) convert moles O to atoms O (via Avogadro's Number). It is important to arrange the conversions in a way that allows for the cancellation of units. The final answer should have 3 sig figs to match the amount of sig figs in the given value.

Molar Mass (CaCO₃): 40.078 g/mol + 12.011 g/mol + 3(15.998 g/mol)

Molar Mass (CaCO₃): 100.083 g/mol

1 CaCO₃ = 1 Ca and 1 C and 3 O

Avogadro's Number:

6.022 x 10²³ atoms = 1 mole

1.00 g CaCO₃           1 mole                 3 moles O           6.022 x 10²³ atoms
----------------------  x  ------------------  x  ----------------------  x  ------------------------------  =
                                100.083 g          1 mole CaCO₃                 1 mole

=  1.81 x 10²² atoms O

Combustion of hydrogen produces electricity:

It would power a 100-watt (W) light bulb in 27.66 min.

Calculation:

At STP conditions, we know that 1 mole of any gas is contained in 22.4L.

So let's make the operation:

The volume of one mole of gas at STP is 22.4 L

Then, 13.0 L may be the volume for (13.0) /22.4  = 0.58 moles.

The total energy is released = 0.58 x 286 kJ

Total energy = 165.98 kJ

Energy = Power x time

Time = energy / power

where power = 100W = 100 J/s

Therefore, Time = 165.98 kJ/ 100J/s = 1659.8 sec

Time = 1659.8 sec / 60 min = 27.66 min

∴ Time = 27.66 min

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Answer:

10.0 g

Explanation:

Avogadro's law states that there are 6.02 × 10²³ molcules in one mole of a substance, so we know that this sample has half a mole of neon.

The atomic mass of neon is 20.1797 g/mol, so 0.5 mol has a mass of about 10.0 g.

it is 10.09 g

According to Avogadro;

1 mole of neon would have 6.022 x 10^23 atoms

3.0 x 10^23 atoms of neon would have:

            3.0 x 10^23/6.022 x 10^23

                                         = 0.5 moles

mass of 0.5 moles neon = mole x molar mass

                                            = 0.5 x 20.18

                                             = 10.09 g

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Two-thirds of a bone's weight is composed of calcium phosphate which interacts with calcium hydroxide to form crystals of hydroxyapatite

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Explanation:

The alimentary canal is the long tube of organs - including stomaches and intestines

Answer: digestive strat.

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The blank is filled by Na₂SO₄, and the complete equation for the double displacement reaction is:

Na₂SO₄ + BaCl₂ = BaSO₄ + 2 NaCl

It is a reaction in which both reactants exchange anions and cations.

Let's consider the following incomplete double displacement reaction.

_____ + BaCl₂ = BaSO₄ + 2 NaCl

If we compare the left and right sides, we can see that the missing ions in the left side are Na⁺ and SO₄²⁻. Thus, the missing compound is Na₂SO₄. The complete equation is:

Na₂SO₄ + BaCl₂ = BaSO₄ + 2 NaCl

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Answer:

See below

Explanation:

From periodic table

mole weight of Fe   is   55.845  gm / mole

76.15 gm  /  55.845 gm/mol   *  6.022 x 10^23  atoms/mole =

                8.212 x 10^23   atoms    ( four signif. digits)

The example that shows the correct way to set up the calculation will be the second example.

Mathematically:

  Number of moles = mass/molar mass

In this case, mass = 23.4 g and molar mass = 110.98 g/mol

Number of moles = 23.4/110.98 = 0.21 moles

Thus, the second example is the correct way.

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The new temperature (in °C) of the gas, given the data is –148.20 °C

The new temperature of the gas can be obtained by using the combined gas equation as illustrated below:

P₁V₁ / T₁ = P₂V₂ / T₂

Since the volume is constant, we have:

P₁ / T₁ = P₂ / T₂

349.84 / 422.05 = 103.45 / T₂

Cross multiply

349.84 × T₂ = 103.45 × 422.05

Divide both side by 349.84

T₂ = (103.45 × 422.05) / 349.84

T₂ = 124.80 K

Subtract 273 from 124.80 K to express in degree celsius

T₂ = 124.80 – 273

T₂ = –148.20 °C

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The correct option is (2) decomposition.

In the balanced equation 2KClO3==> 2KCl + 3O2, as there is a reduction of oxygen therefore it is decomposition reaction.

A chemical reaction that results in the breakdown of one reactant into two or more reactants is known as a decomposition reaction.

The general equation for decomposition is-

AB -> A + B

Where A & B are now the product molecules and AB is the parent (reactant) molecule.

Some key features of the decomposition reaction are-

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The complete question is-

Given the balanced equation:

2KClO3==> 2KCl + 3O2

Which type of reaction is represented by this equation?

(1) synthesis

(2) decomposition

(3) single replacement

(4) double replacement

Based on their composition and structure list CH₂Cl₂, CH₃CH₂CH₃ and CH₃CH₂OH in order of (a) Increasing order of Intermolecular Forces are CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH. (b) Increasing order of Viscosity are CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH. (c) Increasing order of Surface Tension are: CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH.  

Intermolecular forces often abbreviated to IMF (or Secondary force) are the forces that hold atoms together with in a molecule. These forces are electrostatic in nature and exist between molecules.

Increasing order of Intermolecular Forces are: CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH.

Higher the intermolecular force then higher the viscosity. Stronger the intermolecular force then stronger the viscosity.          

Increasing order of Viscosity are: CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH.    

Stronger the intermolecular forces of liquid have higher surface tension. Surface tension depend upon the intermolecular forces.

Increasing order of Surface Tension are: CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH.  

Thus from the above conclusion we can say that Based on their composition and structure list CH₂Cl₂, CH₃CH₂CH₃ and CH₃CH₂OH in order of (a) Increasing order of Intermolecular Forces are CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH. (b) Increasing order of Viscosity are CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH. (c) Increasing order of Surface Tension are: CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH.  

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The concentration of the solution in mass percent is 60%.

The concentration of a substance can be expressed in mass percent. This refers to the percentage of the solute that is contained in the solution.

Thus we can write;

Mass percent = Mass of solute/ Mass of solution * 100/1

Mass percent = 1.5kg/1.5kg + 1 Kg * 100/1

Mass percent =  60%

Hence, the concentration of the solution in mass percent is 60%.

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The correct answer is   [tex]LiCH_{3}CH(CH_{3} )CH_{3}[/tex] .

Organometallic chemistry is the study of organometallic compounds, which are substances that contain at least one chemical bond between a carbon atom from an organic molecule and a metal. These substances include alkali, alkaline earth, and transition metals, as well as metalloids like boron, silicon, and selenium. In addition to links to organyl fragments or molecules, bonds to 'inorganic' carbon, such as those to carbon monoxide (metal carbonyls), cyanide, or carbide, are also typically regarded as organometallic. Although they are not strictly speaking organometallic compounds, some similar compounds, such as transition metal hydrides and metal phosphine complexes, are frequently included in discussions of such substances. The phrase "metalorganic compound," which is comparable but different, describes molecules that contain metals but do not have direct metal-carbon bonds but do have organic ligands.

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Answer:

Pink

Explanation:

Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions.

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Answer:

pink

Explanation:

Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions.

Answer:

0.25 moles

Explanation:

To find the number of moles, you need to use a variation of the Ideal gas Law. The manipulated equation looks like this:

P₁ / n₁ = P₂ / n₂

In this formula, "P₁" and "n₁" represent the initial pressure and number of moles. "P₂" and "n₂" represent the final pressure and number of moles. You can find the final amount of moles by plugging the given values into the equation and simplifying.

P₁ = 10.0 atm                      P₂ = 2.5 atm

n₁ = 1 mole                          n₂ = ? moles

P₁ / n₁ = P₂ / n₂                                                <----- Equation

(10.0 atm) / (1 mole) = (2.5 atm) / n₂               <----- Insert values

10.0 = (2.5 atm) / n₂                                        <----- Divide 1 from 10.0

(10.0) x n₂ = 2.5 atm                                       <----- Multiply both sides by n₂

n₂ = 0.25                                                        <----- Divide both sides by 10.0

1. O2 is the limiting reagent

2. Excess NH3 = 0.102 moles

3. 0.088 mol of NO is formed

4. 2.376 grams of H2O is formed

From the equation: [tex]4NH_3 + 5O_2 --- > 4NO + 6H_2O[/tex]

Mole ratio of NH3 and O2 = 4:5

Mole of 3.25 g NH3 = 3.25/17 = 0.19 mol

Mole of 3.50 g O2 = 3.5/32 = 0.11 mol

Equivalent mole of O2 from NH3 = 5/4 x 0.19 = 0.24 mol

Equivalent mole of NH3 from O2 = 4/5 x 0.11 = 0.088 mol

Thus, O2 is the limiting reagent.

Excess NH3 = 0.19 - 0.088 = 0.102 moles

Mole ratio of O2 and NO = 5:4

Equivalent mole of NO = 4/5 x 0.11 = 0.088 mol

Mole ratio of O2 and H2O = 5:6

Equivalent mole of H2O = 6/5 x 0.11 = 0.132 mol

Mass of 0.132 mol H2O = 0.132 x 18 = 2.376 grams

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Increase in carbon dioxide in your red blood cells, which causes a drop in pH, causes your breathing to speed up.

The presence of  carbon dioxide in red blood cell will lower the pH because  carbon dioxide combines with water to form [tex]H^{+}[/tex] and [tex]HCO_{3} ^{-}[/tex] .

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