ancient hunters used obsidian rock to make spears. given this information, what can you conclude about the minerals in obsidian rock? explain your reasoning.

Answer:

1. There is no moles of water in 39g of chlorine.

2. 1.19x10²³ molecules of Au.

Explanation:

First, we need to remember that molar mass of a compound represents the mass of 1 mole (6.022x10²³ molecules) of molecules.

Molar mass of Chlorine, Cl₂ is 70.9g/mol

Molar mass of gold, Au, is 197g/mol

1. Moles of 39g of Cl₂ are:

39g Cl₂ * (1mol / 70.9g) = 0.55 moles moles of chlorine

But there is no moles of water in 39g of chlorine.

2. First, moles of Au are:

39g Au * (1mol / 197g) = 0.198 moles Au.

Molecules are:

0.198 moles Au * (6.022x10²³ molecules / 1 mol) =

1. HNO₃ (g) + 4H₂ (g) ⇒ NH₃ (g) + 3H₂O (g)

2. Exothermic.

3. 2293.2 kJ

Reaction

HNO₃ (g) + H₂ (g) ⇒ NH₃ (g) + H₂O (g) △H = −637 kJ

1. Balance

give coefficient :

HNO₃ (g) + aH₂ (g) ⇒ bNH₃ (g) + cH₂O (g)

H, left=1+2a, right=3b+2c⇒1+2a=3b+2c(eq 1)

N,left=1, right=b⇒b=1

O,left=3, right=c⇒c=3

eq 1 : 1+2a=3.1+2.3⇒1+2a=9⇒2a=8⇒a=4

Balance reaction :

HNO₃ (g) + 4H₂ (g) ⇒ NH₃ (g) + 3H₂O (g)

2.  exothermic⇒release heat(negative sign)

3. heat released :

mol H₂ :

[tex]\tt mol~H_2=\dfrac{7.2}{2}=3.6[/tex]

heat released :

[tex]\tt -637\times 3.6=-2293.2~kJ[/tex]

Complete Question

10 g of Compound X with molecular formula  [tex]C_4 H_8[/tex]  are burned in a constant-pressure calorimeter containing 45g of water at [tex]25^oC[/tex]. The temperature of the water is observed to rise by 2.432. (You may assume all the heat released by the reaction is absorbed by the water, and none by the calorimeter itself.) Calculate the standard heat of formation of Compound at [tex]25^oC[/tex]

Answer:

The value is  [tex]\Delta H^o_f =-2571 \ J /mol[/tex]

Explanation:

From the question we are told that  

    The mass of compound X is [tex]m = 10 \ g = 0.010 \ kg[/tex]

     The mass of water is  [tex]m_w = 45 \ g = 0.045 \ kg[/tex]

      The temperature of water is  [tex]T_w = 25^oC[/tex]

     The change in the temperature of water is  [tex]\Delta T = 2.432 ^oC[/tex]

Generally the heat adsorbed by water is mathematically represented as

         [tex]Q_{w } = c * m _w * \Delta T[/tex]

Here  c is the specific heat of water with value  [tex]c = 4186 \ J/kg\cdot ^oC[/tex]

         [tex]Q_{w } = 4186 * 0.045 * 2.432[/tex]

=>      [tex]Q_{w } = 458.1 \ J[/tex]

Given that the total heat that was generated by the reaction is absorbed by   water then

        [tex]\Delta H _{rxn} = -Q_w[/tex]

The negative sign shows that the heat was absorbed

        [tex]\Delta H _{rxn} = -458.1 \ J[/tex]

Generally the number of moles of the compound X available is mathematically represented as

              [tex]n = \frac{m}{Z}[/tex]

Here Z is the molar mass of compound X the value is [tex]Z = 56.11 \ g/mol[/tex]

             [tex]n = \frac{m}{Z}[/tex]

=>          [tex]n = \frac{10}{56.11}[/tex]

=>          [tex]n = 0.1782 \ mols[/tex]

Generally the standard heat of formation of Compound X is mathematically  represented as

            [tex]\Delta H^o_f = \frac{\Delta H_{rxn} }{ n}[/tex]

=>         [tex]\Delta H^o_f = \frac{-458.1 }{ 0.1782}[/tex]

=>         [tex]\Delta H^o_f = \frac{-458.1 }{ 0.1782}[/tex]

=>         [tex]\Delta H^o_f =-2571 \ J /mol[/tex]

Answer:

I think the answer is b but I could be wrong. but I believe the answer is b.

Explanation:

because As the popsicle melts, it goes through a change of state or phase change. A change of state when a substance changes physical form but not in molecule make up. The molecules do not change into something different they just gain or lose energy and movement.

With the melting of particles there has been the gain of thermal energy by the particles, that results in speeding up the particles. Thus, option D is correct.

A popsicle has been the ice frozen snack. The popsicle has been present in solid form. The melting of popsicles has been the change in the state of the matter from solid ice form to liquid form.

The change in the state of matter has been achieved with the loss or gain of energy. The solid has been the compact form, and with the gain of energy, there has been the increased motion of solid molecules. The increase in the motion results in the breaking of the attraction forces and results in the phase change.

Thus, when a popsicle melts there has been a gain of energy by the particles and increased motion. Thus, option D is correct.

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Answer:

The final temperature is 181.92°C

Explanation:

Given

Initial Temperature, T1 = 0°C

Initial Volume, V1 = 555mL

Initial Pressure, P1 = 80.0kPa

Final Volume, V2 = 1880ml

Final Pressure, P2 = 39kPa

Required

Determine the Final Temperature, T1

This question illustrates ideal gas law and will be solved using:

(P1 * V1)/T1 = (P2 * V2)/T2

But first, we need to convert temperature to degree Kelvin

T1 = 0°C = 273 + 0 = 273k

Next, we substitute values for P1, V1, T1, P2 and V2

THE EQUATION BEFOMES

(80 * 550)/273 = (1880 * 39)/T2

44000/273 = 73320/T2

Cross Multiply

44000 * T2 = 73320 * 273

44000T2 = 20016360

Solve for T2

T2 = 20016360/44000

T2 = 454.92K

Convert to degree Celsius

T2 = 454.92 - 273

T2 = 181.92°C

Hence, the final temperature is 181.92°C

The ideal gas law, also called the general gas equation, is the equation of the state of a hypothetical ideal gas.

The ideal gas law work under the constant:-

Hence the formula we gonna use is as follows:-

[tex]PV = nRT[/tex]

In the question, the pressure, temperature, and volume are given in two different system

Hence it is equal to

[tex]\frac{PV}{T} = \frac{PV}{T}[/tex]

Put the value given,

[tex]\frac{80*50}{273} = \frac{1880*39}{T}[/tex]

Solving the equation, the value T will be:-

[tex]T2 = \frac{20016360}{44000}[/tex]

=181.92C

The temperature given is 181.92C

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Answer:

when the numbers are very large or very small

Explanation:

good luck

Answer:

CH3-CH2-CH2-CH2-CH2-OH. (1-PENTANOL)

Explanation:

The given compound is Pente-1-ne

Hydroboration oxidation reagent - BH3 +H2O2 + OH-

The reaction is initiated by boron hydride which attacks the terminal carbon because the middle carbon + charge will be stabilized by +I effect of the parent carbon chain. This similar process will happen thrice and all the hydrogens of Boron hydride will be lost and carbon chain of Pent-1-ene will be attached to boron and it will form TRIPENTYL BORANE, Then we will add H2O2+ OH- and finally OH- will be attached to the parent carbon chain and

1-PENTANOL will be formed.

CH3-CH2-CH2-CH=CH2 + HBO → CH3-CH2-CH2-CH2-CH2-OH

                                                               1-PENTANOL

Answer:

Explanation:

The question states that the chemical equations should be balanced and the phases should also be indicated. The abbreviations of the phases have been indicated in the question with

i) (s) meaning the compound is in solid

ii) (aq) meaning the compound is in aqueous form

iii) (l) meaning the compound is in liquid

iv) (g) meaning the compound is in gaseous form

Balanced chemical equation is that in which the number of individual atoms on the reactant side is equivalent to the number of the same individual atoms on the product side.

Only the answer (the balanced chemical equations) will be written below.

A) This reaction is balanced

Mg(s) + Br₂(l) ⇒ MgBr₂(s)

B) P₄(s) + 5O₂(g) ⇒ P₄O₁₀ (s)

C) Ba(OH)₂(aq) + 2HNO₃(aq) ⇒ Ba(NO₃)₂(aq) + 2H₂O

D) Cr₂O₃(s) + 3C(s) ⇒ 2Cr(s) + 3CO(g)

Answer:

See explanation

Explanation:

The electron configuration of an atom means a detailed arrangement of the electrons in the atom in orbitals. It normally begins from the least energetic orbitals to the most energetic orbital.

For each of the elements, their electronic configuration in terms of the nearest noble gas is shown below;

P - [Ne] 3s2 3p3

I- [Kr] 4d10 5s2 5p5

Pb- [Xe] 4f14 5d10 6s2 6p2

F- [He] 2s2 2p5

#P

Phosphorus lies after Neon

EC given by

[tex]\\ \rm\Rrightarrow [Ne]3s^23p^3[/tex]

#I

Lies after Krypton

EC given by

[tex]\\ \rm\Rrightarrow [Kr]5s^24d^105p^5[/tex]

#Pb

EC given by

[tex]\\ \rm\Rrightarrow [Xe]6s^25d^{10}4f^{14}6p^2[/tex]

#

EC given by

[tex]\\ \rm\Rrightarrow [He]2s^22p^5[/tex]

The nurse give 2.3 ml Medrol to the child

Mass is one of the principal quantities, which is related to the matter in the object  

The main mass unit consists of 7 units

kg, hg, dag, g, dg, cg, mg

Conversion :

1 Lb=0,453592 kg

For 71.6 lb :

[tex]\tt 71.6\times 0.453592=32.48~kg[/tex]

Medrol to be given 1.4 mg/kg of body weight, so amount for the child :

[tex]\tt 32.48~kg\times 1.4~mg/kg=45.472~mg[/tex]

The available stock of Medrol is 20. mg/mL, so the volume to the child :

[tex]\tt \dfrac{45.472}{20}=2.2736\approx2.3~ml[/tex]

Answer:

Frequency x Wavelength = Speed of wave

Explanation:

So, if you take the Speed and divide it by wavelength then you get the frequency.

Answer:

The correct answer is D. Multiplying them by Avogadro's number :)

The number of moles of a substance can be converted into molecules by multiplying them by Avogadro's number. Therefore, option (d) is correct.

The Avogadro constant is the proportionality factor that is the number of constituent entities such as molecules, atoms, or ions in one mole of a sample and is commonly denoted [tex]N_A[/tex].

Avogadro's number is a constant with a value of 6.022 × 10²³ reciprocal moles. The numeric value of the Avogadro number is in reciprocal moles, a dimensionless number. The value of the Avogadro constant, is the mass of one mole of a compound (in grams).

The number of moles of a given compound can be calculated as:

Moles = Number of molecules/ Avogadro number

Number of molecules = Moles ×Avogadro number

Therefore, the moles can be converted into molecules by multiplying them by Avogadro's number with the number of moles.

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#SPJ6

Answer:

The energy of a vibrating molecule is quantized much like the energy of an electron in the hydrogen atom. The energy levels of a vibrating molecule are given by the equation: En=(n+21)hv where n is a quantum number with possible values of 1, 2, ... and v is the frequency of vibration.

Explanation:

hope it helps.

have a wonderful day!

Answer:

-2

Explanation:

Magnesium usually has a negative charge.

Answer:

+2

Explanation:

Magnesium has the following electron configuration: 1s^2 2s^2 2p^6 3s^2 or [Ne] 3s2.

You can see that Magnesium contains two electrons in its outermost orbit. It loses these 2 electrons during the chemical reaction and transitions to the closest stable noble gas form. It also generates the Mg2+ ion as it loses two electrons. It has an ionic charge of 2+ as a result.

I hope you now fully comprehend why magnesium has a 2+ charge.

Na₂SO₄ (aq) → 2Na⁺ (aq) + SO4²⁻ (aq) correctly describes the dissociation of sodium sulfate into ions in an aqueous media

Dissociation reactions are those reactions in which a molecule dissociates into their constitute ions.

In the question, dissociation of sodium sulfate takes place as follow:

Na₂SO₄ (aq) → 2Na⁺ (aq) + SO4²⁻ (aq)

Above reaction shows the dissociation of Na₂SO₄ where in the right side sodium ion is present in the +1 oxidation state and sulfate ion is present in the -2 oxidation state.

Hence, option (a) is correctly describes the dissociation.

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Answer:

It would take 15 sticks of butter

Explanation:

2 divided by 20 is 0.1

0.1 is how much butter for 1 so now we multiply that by 150

0.1 x 150 = 15

Therefore, you would need 15 sticks of butter for 150 cookies

Answer:

Pretty sure the answer is d) cells come from nonliving objects

Explanation:

i just think i remember xd

Answer:

2.43 moles of water are require.

Explanation:

Number of moles of water required = ?

Number of moles of NO₂ available = 7.30 mol

Solution:

Chemical equation:

3NO₂ + H₂O     →     NO + 2HNO₃

now we will compare the moles of NO₂ with H₂O.

                         NO₂           :            H₂O

                           3              :              1

                        7.30            :           1/3×7.30 = 2.43 mol

Answer: Warm Water and powdered lemonade.

Explanation: Water is faster at dissolving something and powder takes a smaller effort to dissolve.

Answer:

C

Explanation:

Answer:

What is this asking for?

Explanation:

I’ll put the answer in the comments

Answer:

0.23J/g°C

Explanation:

Given parameters:

Mass of sample  = 135g

Amount of heat  = 2.5kJ

Initial temperature  = 19.5°c

Final temperature  = 100°C

Unknown:

Specific heat capacity of the metal  = ?

Solution:

The specific heat capacity of a substance is the amount of heat required to the raise the temperature of 1g of the substance by 1°C.

   H  = m C (T₂ - T₁ )

H is the amount of heat

m is the mass

C is the specific heat capacity

T₂ is the final temperature

T₁ is the initial temperature;

     2.5 x 10³  = 135 x C x (100 - 19.5)

     2500 = 10867.5C

       C = [tex]\frac{2500}{10867.5}[/tex]   = 0.23J/g°C

Answer:

donate? *transfer* (gain/lose, not share)

crystal

crystals (lattices)/ formula units

repeating (alternating) pattern (of +/- charges, like NaCl)

empirical

smallest

solid (...bc of strong bonds)

aqueous

Explanation:

An ionic bond forms when atoms transfer electrons.

Another name for an ionic compound is a crystal.

Instead of forming molecules, ionic compounds form.

Crystals are 3-dimensional arrays of positive and negative ions in a repeating pattern.

The formula for an ionic compound is called an empirical formula.

The formula for an ionic compound always indicates the smallest whole number ratio of positive to negative ions within the crystal.

Ionic compounds do not conduct electricity in the solid-state but do conduct electricity in the and states.

The aqueous state means that the compound is dissolved in water

An ionic bond is a bond that's formed when there's an electrostatic attraction between the oppositely charged ions. In this case, ionic bond forms when atoms transfer electrons.

It should also be noted that another name for an ionic compound is a crystal. Instead of forming molecules, ionic compounds form crystals.

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mass Zn : 4.77 g

mass HCl : 5.32 g

The reaction equation is the chemical formula of reagents and product substances

A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.

Reaction

[tex]\tt Zn+2HCl\rightarrow ZnCl_2+H_2[/tex]

MW ZnCl₂=136,286 g/mol

[tex]\tt mol=\dfrac{10}{136.286}=0.073[/tex]

mol Zn : mol ZnCl₂ = 0.073

mass Zn :

[tex]\tt 0.073\times 65,38=4.77~g[/tex]

mol ZnCl₂ : mol HCl = 1 : 2

mol HCl :

[tex]\tt 0.073\times 2=0.146[/tex]

mas HCl :

[tex]\tt 0.146\times 36,46=5.32~g[/tex]

Answer:

it B

Explanation:

im goeted like that

Answer:

ok 3 = 9 15 i got 15 so what

Explanation:

Answer:

the answer is true

Explanation:

it is the smallest particle in an element that takes part in a chemical reaction

Explanation:

1. total electrons = 22

2. total electrons = 31

3. total electrons = 37

hope it helps:)

Answer:

1.Argon

2. Scandium

3. Cobalt

Answer:

Molarity of HCl solution = 0.25 M

Explanation:

Given data:

Volume of NaOH= V₁ = 25.0 mL (25/1000 = 0.025 L)

Molarity of NaOH solution=M₁ = 0.185 M

Volume of HCl solution = V₂ = 0.0200 L

Molarity of HCl solution =  M₂= ?

Solution:

M₁V₁   =  M₂V₂

0.185 M ×0.025 L =  M₂ × 0.0200 L

M₂  = 0.185 M ×0.025 L / 0.0200 L

M₂  = 0.005M.L /0.0200 L

M₂  =  0.25 M

The overall chemical equation obtained by combining the intermediate equations is: CH4 + 2O2 → CO2 + 2H2O

According to this question, methane gas reacts with oxygen in a combustion reaction to produce carbon dioxide and water as products.

The chemical equation for the reaction is as follows:

CH4 + O2 → CO2 + H2O

However, the equation is balanced i.e. the number of atoms of each element on both sides of the equation is not the same. We balance the equation using coefficients placed in front of the compound/element as follows:

CH4 + 2O2 → CO2 + 2H2O

Therefore, in words, the correct statement for the balanced equation is: Upper C upper H subscript 4 plus 2 upper O subscript 2 (g) right arrow upper C upper O subscript 2 (g) plus 2 upper H subscript 2 upper O (l).

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Answer:

A on EDGE 2022

Explanation:

Answer:

The answer is B "The lithosphere is characterized by its physical state while the crust is characterized by its composition (mostly oxygen, aluminum, and silicon)