Help please!!! Its chemistry last unit

The number of half-lives that has elapsed since the sample originally formed is 3 half-lives

Original amount (N₀) = 15.4 + 2.2 = 17.6 g

Amount remaining (N) = 2.2 g

Number of half-lives (n) = ?

2ⁿ = N₀ / N

2ⁿ = 17.6 / 2.2

2ⁿ = 8

2ⁿ = 2³

n = 3

Thus, 3 half-lives has elapsed

Learn more about half life:

https://brainly.com/question/26374513

#SPJ4

Answer:

3

Explanation:

e2022

This particular alkane is distinguished from all the other alknes by reason of the shape of the alkane.

The term alkanes has to do compounds that have only a carbon to carbon single bond. We have to note that alknaes can be cyclic, linear or branched. All this types of alkanes are easily recognized by shape.

This particular alkane is distinguished from all the other alknes by reason of the shape of the alkane.

Learn more about alkanes:https://brainly.com/question/4260635

#SPJ4

Answer: A) The shape

Explanation:

edge 22 - took the quiz and got it correct

hope it helps <3

Answer:

the name is Carbon monoxide.

Good luck.

The pH of the solutions is 12.67.  

pH is the measurement of how acidic or basic a solution is. The range of pH values is from 0 to 14. Lower pH values mean higher acidity, while higher pH means higher basicity. If the pH value is equal to 7, then the solution is neutral.

To calculate the pH of the solution, a few approaches are possible. Here, the pOH of the solution is calculated first using the molar concentration of  [tex]OH^{-1}[/tex] ions. Because pH + pOH = 14, the pH of the solution can then be calculated by subtracting pOH from 14.

Because 2 moles of [tex]OH^{-1}[/tex] ions are formed per mole of [tex]Ca(OH)_{2}[/tex]dissolved, the pOH of a saturated [tex]Ca(OH)_{2}[/tex] solution at  [tex]20^{.C}[/tex] is,  

Concentration ([tex]C_{OH}[/tex]) of [tex]OH^{-1}[/tex] ions,

          [tex]C_{OH}[/tex]   = 0.02335 mol [tex]Ca(OH)_{2}[/tex]/L  X 2 mol [tex]OH^{-1}[/tex] /1 mol [tex]Ca(OH)_{2}[/tex]

            [tex]C_{OH}[/tex] = 0.0467 mol [tex]OH^{-1}[/tex]/L

*pOH of saturated [tex]Ca(OH)_{2}[/tex] solution,

                                   pOH = -log [[tex]C_{OH}[/tex]]

                                   pOH = -log [0.0467 mol [tex]OH^{-1}[/tex]/L ]            

                                  pOH = 1.33  

*pH of saturated [tex]Ca(OH)_{2}[/tex] solution,

                                   pH = 14 - 1.33

                                   pH = 12.67

Hence, the pH of the solutions is 12.67.

Learn more about  pH of the solutions here:

https://brainly.com/question/6988456

#SPJ4

Answer:

In voltaic cells, oxidation occurs at an anode (-), reduction at a cathode (+), and electrons flow from anode to cathode. In electrolytic cells, oxidation occurs at an anode, reduction occurs at a cathode, and electrons flow from anode to cathode.

Explanation:

pH is the concentration of the hydrogen ion in the solution. The value of Ka for hydrogen fluoride is 2.7688.

pH is the potential of the hydrogen or the hydronium ion in the solution that depicts the acidic or the basic character of the solution.

Given,

pH = 2.3

Concentration of hydrogen fluoride = 0.25 M

The concentration of hydrogen ion is calculated as:

[tex]\begin{aligned} \rm pH & = \rm - log [H^{+}]\\\\2.3 &= \rm - log [H^{+}]\\\\&= 0.832\;\rm M\end{aligned}[/tex]

Ka is calculated as:

[tex]\begin{aligned} \rm Ka &= \rm \dfrac{[H^{+}]F^{-}]}{[HF]}\\\\&= \dfrac{0.832 \times 0.832}{0.25}\\\\&= 2.7688\end{aligned}[/tex]

Therefore, 2.7688 is the Ka for hydrogen fluoride.

Learn more about Ka here:

https://brainly.com/question/9938114

#SPJ4

Explanation:

Global warming indeed is a big problem to us. But not only us, it is a big problem to all living things on the Earth. Global warming as everyone knows is a topic that has been with us for a long time. Global warming happens in multiple ways like deforestation, due to harmful gases (Like carbon doxide) and etc... Global warming simple means that our Globe is warming or is heating up. This is a big problem to all living things on Earth.

It is a big problem to us because increase in temperature throughout the globe and due to this Ice in the Antarctic and the Arctic is melting and is causing damage to habitat of animals and also this is causing the sea level to rise and also this is wasting drinking water that us humans have. So this is clearly a problem to all.

But there is good news that now because people are now starting to care for the planet by reducing the amount of harmful gases released to the environment and also starting Reforestation programs.

So In my opinion Global warming is a big problem to all living things on Earth.

Answer: …

Explanation:

HI does not have any hydrogen atoms, it cannot exhibit hydrogen bonding instead HI is a heteronuclear diatomic molecule show dipole-dipole intermolecular force.

The forces of attraction or repulsion among the particles of atoms or molecules in either solid, liquid, or gaseous state For example covalent bond.

These forces are weaker than Intramolecular Forces and the strength of the intermolecular forces of attraction explain the type of interaction that will occur between two molecules.

Intermolecular forces involve in both structural features and physical properties of the substance.

This force seen in the  same molecule or a polyatomic ion affect the chemical properties of the substance.

Water is the best studied example of Intermolecular forces of attraction.

Different types of intermolecular forces are Dipole-dipole interactions, Dipole-induced dipole,  Ion-dipole interactions, Ion-induced dipole interactions, Dispersion forces, Hydrogen bonding

Learn more about intermolecular forces  , here:

https://brainly.com/question/28170469

#SPJ2

Joe Viskocil is not a fan of big explosions because it is is either lopsided or squashed and not spherical.

This is defined as a sudden, violent burst of energy which is associated with a rapid expansion of volume.

Joe Viskocil doesn't like big explosions because it is is either lopsided or squashed. and capable of creating more damage.

Read more about Explosion here https://brainly.com/question/542401

#SPJ1

Answer:

C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(g)

88.0g ………………….. ………………………..?g

88.0g C3H8 x (1 mol C3H8 / 44.0g C3H8) x (4 mol H2O / 1 mol C3H8) x (18.0g H2O / 1 mol H2O) = 144g H2O

option A Hydrogen will have the greatest rate of effusion beacuse it has the least mass among all

Answer:

20C is warmer.

Explanation:

20C is 68 fehrenheit

20K is -423.67 fahrenheit

Answer:

His gold foil experiment showed that the atom is mostly empty space with a tiny dense positively-charged nucleus. Based on those results, Rutherford was able to propose the nuclear model of the atom.

Answer:

Explanation:

If the gas pops when the top of the test tube is placed close to a flame it is hydrogen,

If it re-ignites a glowing splint it's oxygen.

Otherwise the gas is nitrogen.

Answer: it’s A historical article is a kind of scholarly papers where the writer recounts the account of somebody's life.

Explanation: Brainlest please

Answer:

Heat gains or losses result in changes in temperature, changes in state or the performance of work. Heat is a transfer of energy. When gained or lost by an object, there will be corresponding energy changes within that object.

Answer:

102.8312649 --> 103%

The marbles there must not be any hear going anywhere else. If any heat energy warmed up anything else in the system then that is heat that did not go to the marbles.

[tex]\frac{Answer D}{Answer E} x 100 = ???[/tex]

(This is the equasion I used to got my answer)

2119.121 / 2060.775 x 100 = ???

2119.121 / 2060.775 = 1.028312649

1.028312649 x 100 = 102.8312649

102.8312649 --> 103%

Answer

34g

Explanation:

equation:2H2O2 ------------ 2H2O + O2

mole ratio:  2:               2      :     1

RMM of O2 - (16*2) = 32

RFM of H2O2 - (1*2) + (16*2) = 34

1 MOLE O2 - 32g

     ?            -  1.6g

1.6/32 = 0.5 MOLES

0.5*2 = 1 MOLE OF H2O2

I*34 = 34 g

Answer:

solid liquid and gas

Explanation:

Answer:

Minerals can be identified by their color, luster, streak, cleavage, hardness, and even by their chemical composition. Using these properties is one way a Geologist defines and identifies what kind of mineral a specimen is.

Answer:

Neutron

Explanation:

The state of the compounds are:

Na₂co₃- basic salt

NaHC₂O₄- acidic

FeCl₃- acidic

NH₄br- acidic

KClO₄- neutral

The state of the compound is its acidity, basicity, and neutrality. The compounds are the mixture of opposite elements.

Thus, the state of the compounds are:

Na₂co₃- basic salt

NaHC₂O₄- acidic

FeCl₃- acidic

NH₄br- acidic

KClO₄- neutral

Learn more about state of the compound

https://brainly.com/question/17140817

#SPJ4

Na₂CO₃, NaHC₂O₄ and FeCl₃ are basic, acidic and acidic respectively.

pH scale is used to define the nature of a substance as acidic, basic or neutral. Value from 0 to 6.9 shows the acidity, 7 shows the neutrality and from 7.1 to 14 shows the basicity.

Hence, Na₂CO₃, NaHC₂O₄ and, FeCl₃ are basic, acidic and acidic respectively.

To know more about acidity and basicity, visit the below link:

https://brainly.com/question/3103303

#SPJ4

The amount of Neon gas with the given volume and at the given temperature and pressure is 0.21 mol.

Option C) 0.21 mol is the correct answer.

The Ideal gas law or general gas equation emphasizes on the state or behavior of a hypothetical ideal gas. It states that "the pressure multiplied by volume is equal to moles multiply by the universal gas constant multiply by temperature.

It is expressed as;

PV = nRT

Where P is pressure, V is volume, n is the amount of substance, T is temperature and R is the ideal gas constant ( 0.08206 Latm/molK )

Given that;

PV = nRT

n = PV / RT

n = ( 4.6atm × 0.84L ) / ( 0.0821 Latm/molK × 222K )

n = ( 3.864Latm ) / ( 18.2262Latm/mol )

n = 0.21 mol

Therefore, the amount of Neon gas with the given volume and at the given temperature and pressure is 0.21 mol.

Option C) 0.21 mol is the correct answer.

Learn more about Ideal Gas Law here: brainly.com/question/4147359

#SPJ1

The acid ionization constant (ka) of an unknown acid if a 0.030M solution of it has a pH of 2.946 is 4.8×10⁻⁵.

Relation between the pH and [H⁺] will be shown as:

[H⁺] = [tex]10^{-pH}[/tex]

Given that pH of solution = 2.946

[H⁺] = [tex]10^{-2.946}[/tex] = 0.00113 = 0.0012

Let the ICE table for the unknown acid HA will be:

                                   HA    ⇄    H⁺   +     A⁻

Initial:                          0.03          0           0

Change:                   -0.0012    0.0012   0.0012

Equilibrium:        0.03-0.0012  0.0012   0.0012

Acid dissociation constant will be calculated as:
Ka = [0.0012][0.0012] / [0.03-0.0012]

Value of 0.0012 is very small as compared to the 0.03, so the equation becomes

Ka = (0.0012)² / 0.03 = 0.000048 = 4.8×10⁻⁵

Hence value of Ka is 4.8×10⁻⁵.

To know more about acid dissociation constant, visit the below link:

https://brainly.com/question/1614600

#SPJ4

Answer:

148.8 ml

Explanation:

V1/T1 = V2/T2

T2 * V1/T1  = V2      (T must be in K units)

(118 + 273.15) * 126 /(58 + 273.15) = 148.8 ml

2CaCO3 =2CaO+CO2 is balanced but we can change 2CaCO =2CaO3+C03

Answer: C

Explanation: