the illustration shows how sonar can be used to study the deep ocean which type of waves does sonar use

Answer:

The climate was wet and cold

Explanation:

Answer:

The large tree rings allow you to conclude that the climate was either very warm or wet during those growing seasons, because greater than normal growth occurred.

Explanation: It is the edge sample response

Answer:

1234567i9812345678912121212121

Answer:

Explanation:

a )

half life = 1600 years

50% in 1600 years

25% in next 1600 years

so 25% in total of 3200 years .

b )

disintegration constant = .693 / half life

= .693 / 1600

λ= 4.33 x 10⁻⁴ year⁻¹

m(t) = [tex]m_0e^{-\lambda t }[/tex]

m₀ is initial mass , λ =  4.33 x 10⁻⁴ year⁻¹

c )

m(t) after 3000 years , t = 3000

m(t) = [tex]m_0e^{-4.33\times10^{-4 }\times 3000 }[/tex]

= [tex]m_0e^{-1.3}[/tex]

= .2725 m₀

percentage of mass remaining = 27.25 %

25% radium-226 remain after 3200 years. 6.82 mg of sample remains after 3000 years. 15 mg of the sample will stay long about 1179. 19 years.

Half life of radium-226 = 1600 years

half-life, in radioactivity, the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay.

Calculation of each part can be done as

a )

half-life = 1600 years

50% in 1600 years

25% in next 1600 years

so 25% in total of 3200 years .

b )

Let decay function is

[tex]m(t) = m_o e^{-kt} \ \ \ \ \ ...(i)\\[/tex]

where k is decay constant

At half life,

[tex]m(t) = \frac{m_o}{2},t= 1600\ years\\So,\ \frac{m_o}{2} = m_oe^{-k1600}\\\frac{1}{2} = e^{-k1600}\\[/tex]

applying log on both sides

[tex]ln \frac{1}{2} = lne^{-1600k}\\-0.693147 = -1600 k \\k =\frac {0.693147}{1600}\\k = 4.332\times10^{-4}\\[/tex]

substitute the value of k in equation (i)

[tex]m(t) = m_oe^{-4.332\times10^{-4t}}\\m(t) = 25e^{-0.0004332t}[/tex]

c) when t = 3000 years

[tex]m(t) = 25e^{-0.0004332t}[/tex]

[tex]m(3000) = 25e^{-0.0004332\times3000}[/tex]

remain sample after 3000 years = 6.82 mg

d) when m(t) = 15 mg

[tex]15 = 25e^{-0.0004332t}\\e^{-0.0004332 t} = \frac{15}{25}\\applying\ log\ on\ both\ side\\ln \ e^{-0.0004332t}=ln(\frac{15}{25)}\\-0.0004332t = -0.510825\\t=\frac{0.510825}{0.0004332}\\t= 1179.19 \ years[/tex]

Hence, this is the required answer.

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Answer:

1chemical properties

2.chrmistry

3.precipitate

4.endothermic reaction

5.matter

6.physical property

7.chemical change

8.exothermic reaction

9.physical change

Answer:

It is A.

Explanation:

I took the test.

The Lewis structure shows the arrangement of valence electrons in H3PO4.

The Lewis structure gives us a picture of the number of valence electrons in a molecule. This is because, in a Lewis structure, the electrons in the molecule are shown as dots. A single line may be used to show shared electrons in a covalent bond.

The correct Lewis structure of H3PO4 is an upper P is single bonded above to an O, and to the left, right, and below to an O single bonded to an H. The O above the P has three pairs of dots to the left, above, and below; the O's to the sides have pairs of dots above and below, and the O below the P has pairs of dots right and left.

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Answer:

Am coming to answer you ok

Answer:

The answer is C (filler)

Answer: b hope im not wrong

Explanation:

Answer:

Option 4

Explanation:

Hydrochloric acid is a strong one, that gives protons to medium. It can be dissociated as this:

HCl  →  H⁺  + Cl⁻

M means Molarity. It is a sort of concentration that indicates the moles of solute in 1L of solution.

M = moles / volume (L)

We can also say M = mmoles / mL of solution

M . mL = mmoles

0.453 M . 62.85mL = 28.5 mmoles

If we divide by 1000 → 28.5 mmol . 1 mol / 1000 mmol = 0.0285

Answer:

it is b

Explanation:

i just took test b

Answer:

C  maneeeee

:)

Explanation:

Answer:

n = 5 to n = 6 absorption

n = 9 to n = 6 emission

n = 6 to n = 4 emission

n = 6 to n = 7 absorption

Explanation:

According to the Bohr's model of the atom. An electron in an atom may absorb energy and move from a lower energy level to a higher energy level. This requires absorption of energy that is equal to the energy difference between the two levels.

Similarly, an electron may move from a higher to a lower energy level, releasing energy that is equal to the energy difference between the higher and the lower level. This is known as emission.

Hence, if the electron is moving from a lower energy level to a higher energy level, an absorption has taken place, e.g n = 5 to n = 6

When an electron moves from a higher energy level to a lower energy level, an emission has taken place e.g n = 9 to n = 6

Answer:

I think it's b probably wrong

Answer:

Explanation:

no of molecules=5.65*10^21

NA=6.23*10^23

no of moles=no of molecules/avogadro number

no of moles=5.65*10^21/6.23*10^23

no of moles=9.07*10^-3

now we know that

no of moles=mass/molar mass

mass=no of moles*molar mass

mass=9.07*10^-3*89.06

mass=0.808 g

Answer:

20atm

Explanation:

according to boyles law P1V1= P2V2

Answer:

answer is  b.12

Explanation:

Rate of Sulfur dioxide : 2730.44 mL/s

Graham's law: the rate of effusion of a gas is inversely proportional to the square root of its molar masses or  

the effusion rates of two gases = the square root of the inverse of their molar masses:  

[tex]\rm \dfrac{r_1}{r_2}=\sqrt{\dfrac{M_2}{M_1} }[/tex]

or  

[tex]\rm M_1\times r_1^2=M_2\times r_2^2[/tex]

MW of N₂ = 28 g/mol

MW SO₂ = 64 g/mol

[tex]\tt 28\times 79^2=64\times r_2^2\\\\r_2^2=\dfrac{28\times 79^2}{64}=2730.44~mL/s[/tex]

Answer:

Number of moles = 0.94 mol

Explanation:

Given data:

Number of moles of sodium chloride = ?

Volume of sodium chloride = 1.25 L

Concentration of solution = 0.750 mol/L

Solution:

Formula:

Concentration = number of moles/ volume in L

By putting values.

0.750 mol/L = number of mole / 1.25 L

Number of moles =  0.750 mol/L×1.25 L

Number of moles = 0.94 mol

Answer:

-251.9°C

Explanation:

Given data:

Initial volume = 35.0 L

Initial pressure = 4.62 atm

Initial temperature = -10.0 °C (-10.0 +273 = 263.0 K)

Final temperature = ?

Final volume = 15.0 L

Final pressure = 8.71 atm

Solution:

According to general gas equation:

P₁V₁/T₁ = P₂V₂/T₂

Now we will put the values,

4.62 atm × 35.0 L / 263.0 K =  8.71 atm ×  15.0 L  /T₂

T₂  = 8.71 atm ×  15.0 L ×   263.0 K /  4.62 atm × 35.0 L

T₂  = 34360.95 atm.L.K /161.7 atm.L

T₂  = 21.26 K

Kelvin to °C:

21.26 - 273.15 K = -251.9°C

Answer:

150ml

Explanation:

For this question,

NaOH completely dissociates. It is a strong base

HCl also completely dissociates. It is a strong acid

So we have this equation

m1v1 = m2v2 ----> equation 1

M2 = 2m

V1= ??

M2 = 6m

V2 = 50m

When we input these into equation 1, we have:

2m x v1 = 6m x 50ml

V1 = 6m x 50ml/2

V1 = 300/2

V1 = 150ml

Therefore NaOH that is required to neutralize the solution of hydrochloric acid is 150ml.

Thank you

Answer:

Oxygen receives two electrons from magnesium

Explanation:

Answer:

The four main categories of mineral formation are: (1) igneous, or magmatic, in which minerals crystallize from a melt, (2) sedimentary, in which minerals are the result of sedimentation, a process whose raw materials are particles from other rocks that have undergone weathering or erosion, (3) metamorphic, in which new minerals form at the expense of earlier ones owing to the effects of changing—usually increasing—temperature or pressure or both on some existing rock type, and (4) hydrothermal, in which minerals are chemically precipitated from hot solutions within Earth.

The mineral can be formed from volcanic gases, oxidation, crystallization from magma, sediment formation, or deposition from a saline fluid.

A rock can be described as a collection of minerals. A rock that becomes so hot it melts and many minerals come out in liquids that are hot enough to melt rocks.

Magma can be defined as a melted rock inside Earth, a molten mixture of substances that can be hot to more than 1,000°C. When the magma cools slowly inside the earth, which provides mineral crystals time to grow large enough.

Granite is a rock that produces from slowly cooled magma, consisting of the minerals quartz, plagioclase feldspar which is shiny white, pink potassium feldspar, and black biotite.

When magma will erupt onto the surface of the Earth, it is known as lava. Lava cools more rapidly than magma when it is below the surface and mineral crystals do not have time to form. But the chemical composition remains the same as if the magma cooled slowly.

The mineral can be formed through hydrothermal processes, weathering, and metamorphic and igneous environments.

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Answer:

The description is outlined in subsection downwards and according to the query given.

Explanation:

The solubility of a soap is due to the hydrophilic head which interacts with water.

A triglyceride is a compound that is based on propane 1,2,3 - triol where all the -OH groups have been replaced with fatty acid chains. The triglycerides are insoluble in water because it contains a long alkyl chain which does not interact with water.

However, a soap is a salt of a glyceride having a hydrophilic head and a hydrophobic tail. The hydrophilic head is responsible for the solubility of the soap in water.

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Answer:

The correct answer is e. 0.40 M

Explanation:

Ba(OH)₂ is a strong base, so it is completely dissociated into ions in aqueous solution:

Ba(OH)₂ → Ba²⁺ + 2 OH⁺

We know that pH + pOH = 14. Thus, we can calculate pOH as follows:

pOH = 14 - pH = 14 - 13.9 = 0.1

According to the definition, pOH = - log [OH⁻]. So, we calculate the concentration of OH⁻:

[OH⁻] = [tex]10^{-pOH}[/tex] = [tex]10^{-0.1}[/tex] = 0.79 M

Since, the dissociation equilibrium of Ba(OH)₂ shows that there are 2 moles of OH⁻ per mole of Ba(OH)₂, the concentration of Ba(OH)₂ is:

[Ba(OH)₂]= [OH⁻]/2 = 0.79 M/2= 0.397 M ≅ 0.4 M

Answer:

Mantle convection

Explanation:

The source of the force that moves tectonic plates along plate boundaries is as a result of the mantle convection.

Answer:

b. decreases

Explanation:

i just took a test on it

As you move from N to Bi, the metallic properties of the element decrease. The correct option is B.

Nitrogen is a chemical element, whose chemical element is N. Nitrogen is a gas and its atomic number is 7. It is a non-metal and is present in group 15 of the periodic table.

Bismuth is a chemical element, whose chemical element is Bi. It is a post-transition metal, and it is also present in group 15 of the periodic table near arsenic and antimony. Its atomic number is 83.

Now, nitrogen and bismuth are present in the same line and group. Nitrogen is the first element of the group and going down, there is bismuth present in the group last. So the metallic property decreases from going down the group.

Thus, the correct option is B. decreases.

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Moles of MgF₂ : 1.2 x 10⁻⁴

Maybe the complete question is like this

A student prepares 100. mL of a saturated solution of MgF2 by adding 0.50 g of solid MgF2 to 100. mL  of distilled water at 25°C and stirring until no more solid dissolves. (Assume that the volume of the  undissolved MgF2 is negligibly small.) The saturated solution is analyzed, and it is determined that [F−] in  the solution is 2.4 × 10−3 M.

The dissociation reaction of MgF₂

MgF₂(s)⇒ Mg²⁺(aq)+2F⁻(aq)

mol ratio MgF₂ : F⁻ = 1 : 2

mol of F⁻ in 100 ml solution :

[tex]\tt mol=M\times V\\\\mol=2.4\times 10^{-3}\times 0.1=2.4\times 10^{-4}[/tex]

mol MgF₂ :

[tex]\tt \dfrac{1}{2}\times 2.4\times 10^{-4}= 1.2\times 10^{-4}[/tex]

Answer:

The sodium has more moles.

n(Na)=2.09 mole

n(O)=0.999 mole

Answer:

P1 = 21.23 atm

Explanation:

Initial Volume V1 = 11.95 L

Final Volume V2 = 5.24L

Final Pressure P2 = 9.31 atm

Initial Pressure P1 = x

The relationship between these values is given as;

P1 / V1 = P2 / V2

P1 / 11.95 = 9.31 / 5.24

P1 = 21.23 atm

Answer:

True

Explanation:

Suspensions are referred to as mixtures composed of materials which are visible to the naked eyes . They are usually insoluble in the solvent .

The mixtures which are composed of materials and at the same time non visible to the naked eyes due to their very tiny size are referred to as colloids or colloidal particles in the field of science.