Scientists are experimenting with pure samples of isotope X which is radioactive. The sample has a mass of 20. Grams. The half-life was measured to be 232 seconds. There is a second sample that weighs 80 grams. What is the half-life of the second sample

Answer:

Zn(s) + Fe(NO₃)₂(aq) ⇒ Zn(NO₃)₂(aq) + Fe(s)

Explanation:

When metal zinc is added to an iron (II) nitrate solution, we can see the following redox reaction:

Zn(s) + Fe(NO₃)₂(aq) ⇒ Zn(NO₃)₂(aq) + Fe(s)

Zinc is oxidized since its oxidation number increases from 0 to +2.

Iron is reduced since its oxidation number decreases from +2 to 0.

Answer:

[tex]k=6.48x10^{-3}M^{-1}s^{-1}[/tex]

Explanation:

Hello.

In this case, based on the given information, we can write the rate law as shown below:

[tex]r=k[H_2O_2][KI][/tex]

Since the overall order of reaction is 2 being 1 for reach reactant. Thus, by knowing the initial rate and concentrations, the rate constant turns out:

[tex]k=\frac{r}{[H_2O_2][KI]}=\frac{7.50x10^{-4}M/s}{0.546M*0.212M}\\ \\k=6.48x10^{-3}M^{-1}s^{-1}[/tex]

Best regards!

The rate constant, k is [tex]6.48x10^{-3}M^{-1}s^{-1}[/tex]

The rate law should be

[tex]r = k[H_2O_2]{KI}[/tex]

Since the total order of the reaction is 2 being 1 for reach reactant. So, by knowing the beginning rate and concentrations, the rate constant turns out:

[tex]k = \frac{r}{k[H_2O_2]{KI}} = \frac{7.50x10^{-4}M/s}{0.546M\times 0.212M}[/tex]

k = [tex]6.48x10^{-3}M^{-1}s^{-1}[/tex]

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Answer:

SBr2: Electron geometry-tetrahedral; molecular geometry-trigonal pyramidal

PI4+: Electron geometry-tetrahedral; molecular geometry-tetrahedral

IBr2−: Electron geometry- Trigonal bipyramidal ; molecular geometry- linear

Explanation:

In SBr2, the molecule is of the structure type AX2E2 hence it is based on a tetrahedron but have two lone pairs of electrons hence the molecular geometry is trigonal pyramidal.

PI4+ has four electron domains and all of them are bond pairs hence both electron geometry and molecular geometry are both tetrahedral.

IBr2- is of the structure type AX2E3 hence it is based on a trigonal bipyramd and has a linear molecular geometry.

2)

SiF4 has a tetrahedral molecular and electron domain geometry because the central atom(Si) has no lone pairs.

SeF4 has a trigonal bipyramidal electron geometry with the structure AX4E. Its molecular geometry is See-saw since it has one lone pair of electrons that causes a deviation from its ideal trigonal bypyramidal geometry.

XeF4 has  an octahedral electron domain geometry and the molecule is AX4E2. The two lone pairs are positioned above and below the plane of a square hence the molecule is square planar.

Answer:

A

Explanation:

Slow cooling of magma beneath the surface of earth

To solve this we must be knowing each and every concept related to rock and its formation. Therefore, the correct option is option A among all the given options.

Rock is a naturally occurring mineral aggregate that is cohesive and composed of one or even more minerals. These aggregates often take the shape of recognisable and mappable volumes and are the fundamental building block of the solid Earth.

Mineral crystals as well as the sorts of rocks that serve as their hosts cycle through many forms as geologic materials. Temperature, weight, time, and variations in the climate in the Earth's crust and on its surface all play a role in the process. Slow cooling of magma beneath the surface of Earth is the  statement that best describes the formation of rock.

Therefore, the correct option is option A.

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#SPJ2

1 valence electron

Explanation:

It is because the metal having one valence electron can readily lose single electron from its outermost shell.

Answer: the answer is 1 valence electron

Explanation: just did a test with this quest thx for the points good luck :D

Answer:

48000

Explanation:

maths

Answer:

48000

Explanation:

(5x10^3) = 5 × 1000 = 5000

(4.3x10^4) = 4.3 × 10000 = 43000

5000 + 43000 = 48000

Answer:

6.25e-6 is the value of the equilibrium constant

Explanation:

we have this equation

[tex]PbBr(s) ----- Pb^{2+}(aq) + 2Br(aq)[/tex]

When at a state of equilibrium,

we have the concentration of Pb^2+ to be 0.01

we have the concentration of Br^- to be 0.025

the equilibrium constant concentration of both pure solids and liquid s are said to be equal to 1

[PbBR2] = 1

such tht

Keq = [Pb^2+] x [Br-]^2

we already know the values of these from the above.

0.01x0.025^2

= 0.01 x 0.000625

= 0.00000625

= 6.25 x 10^-6

= 6.25e^-6

Answer:

1.what I observe.

Explanation:

The dependent variable in an experiment is what is being observed in the experimental procedure.

This variable is the one that is closely tied to the effects originating from changing the independent variables.

Answer:

See detailed explanation.

Explanation:

Hello.

In this case, it is firstly necessary to cite that EGS accounts enhanced geothermal systems which are man-made reservoirs, placed where lots of  hot rock is present but there is lack natural permeability, which requires a fluid to be injected into the subsurface to re-open it and therefore creating permeability.

Typically, water has been used for this purpose, but due to the current issue on saving water alternative methods such as supercritical fluids has been being implemented because they have better dynamic properties such as lower viscosities and therefore larger flow velocities, supercritical CO2 is easy and cheap to get as low temperatures are required to turn it in supercritical condition.

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Answer:

xanthophyll

xenobiotic

xenon

X group

x-rays

x-ray tube

Answer:

trees

Explanation:

we plant trees hindi sure kung tama to hihi

Answer:

Organisms and humans depend on each other to get by. Environmental science is important because it enables you to understand how these relationships work.

For example, humans breathe out carbon dioxide, which plants need for photosynthesis. Plants, on the other hand, produce and release oxygen to the atmosphere, which humans need for respiration.

Animal droppings are sources of nutrients for plants and other microorganisms. Plants are sources of food for humans and animals. In short, organisms and humans depend on each other for survival.

Explanation:

Answer:

Exothermic reactions feel hot

Endothermic reactions feel cool

Explanation:

In an exothermic reaction, heat is given out by the system. The energy of the reactants is greater than that of the products hence the excess energy is given off as heat. The reaction vessel feels hot.

In an endothermic reaction, the energy of products is greater than that of the reactants hence energy is taken into the system and the reaction vessel feels cool.

Answer:

Molecular Formula Fe2O12S3·5H2O

IUPAC Name iron(3+);tri sulfate;pentahydrate

Explanation:

Answer:

19. Option B. ⁰₋₁B

20. Option D. ²¹⁰₈₄Po

Explanation:

19. ²²⁸₈₈Ra —> ²²⁸₈₉Ac + ʸₓZ

Thus, we can determine ʸₓZ as follow:

228 = 228 + y

Collect like terms

228 – 228 = y

y = 0

88 = 89 + x

Collect like terms

88 – 89 = x

x = –1

Thus,

ʸ ₓZ => ⁰₋₁Z => ⁰₋₁B

²²⁸₈₈Ra —> ²²⁸₈₉Ac + ʸₓZ

²²⁸₈₈Ra —> ²²⁸₈₉Ac + ⁰₋₁B

20. ᵘᵥX —> ²⁰⁶₈₂Pb + ⁴₂He

Thus, we can determine ᵘᵥX as follow:

u = 206 + 4

u = 210

v = 82 + 2

v = 84

Thus,

ᵘᵥX => ²¹⁰₈₄X => ²¹⁰₈₄Po

ᵘᵥX —> ²⁰⁶₈₂Pb + ⁴₂He

²¹⁰₈₄Po —> ²⁰⁶₈₂Pb + ⁴₂He

Answer:

Explanation:

In order to calculate the molarity of the solution we use the formula

[tex]c = \frac{n}{v} \\ [/tex]

where

c is the molarity

n is the number of moles

v is the volume in dm³

From the question

n = 7 mol

v = 9 L = 9 dm³

We have

[tex]c = \frac{7}{9} \\ = 0.77777777...[/tex]

We have the final answer as

Hope this helps you

Answer:

witch one witch species witch bone of 1 and 2

Answer:

Yes, process 1 has an advantage over process 2 for the planarian worm. Process 1 requires only one parent. If the planarian can’t find a mate, the life cycle will continue because it can still reproduce.

Explanation:

i did it

Answer:

Salinity, along with temperature, determines the density of seawater, and hence its vertical flow patterns in thermohaline circulation. 2. Salinity records the physical processes affecting a water mass when it was last at the surface. Hope this helps!

Explanation:

Answer:

the real answer is Iceland, Norway, Antarctica.

Explanation:

It is not Green land proof Glaciers are not an unusual sight in Greenland due to the gigantic ice sheet that covers most of the country. However, there are only a few places where the glaciers occur immediately adjacent to a town, and therefore can be appreciated on an excursion.  

proof for Antarctica These large-scale features of glacial erosion can be seen in Antarctica where rock protrudes above the surface of the ice sheet There are many glaciers in the Antarctic. ... The lists include outlet glaciers, valley glaciers, cirque glaciers, tidewater glaciers and ice streams. Ice streams are a type of glacier and many of them have "glacier" in their name, e.g. Pine Island Glacier

proof for Norway are the largest glaciers on mainland Norway. ... In total, Norway has around 1,600 glaciers - 900 of these are in North Norway, but 60% of the total glacier area is south of Trøndelag. 1% of mainland Norway is covered by glaciers.

proof for Iceland Glaciers in Iceland are among the best natural wonders in the world. In fact, the country's glaciers are so great that you can see them from space! With 11% of the total land area covered by ice caps, Iceland is a glacier paradise. Here are the five most amazing glaciers that you must see when visiting Iceland!

Answer:

Solution-

From the question the volume of water = 18 L = 18000 mL

Now we can find the mass of water = (volume of water) * (density of water)

mass of water = (18000 mL) * (1.00 g/mL)

mass of water = 18000 g

Now we find the heat required to boil water = (mass of water) * (specific heat water) * (final temperature - initial temperature)

putting the value the heat required to boil water = (18000 g) * (4.184 J/g.oC) * (100 oC - 22.7 oC)

heat required to boil water = 5821617.6 J

heat required to boil water = 5821.62 kJ

The heat given by the combustion = (heat required to boil water) / (percent of heat taken by boiling)

Heat given by combustion = (5821.62 kJ) / (19.4 /100)

Therefore the heat given by combustion = (5821.62 kJ) / (0.194)

Heat given by combustion = 30008.35 kJ

As we know that the enthalpy of combustion of methane = 802.5 kJ/mol

The moles methane used = (Heat given by combustion) / (enthalpy of combustion of methane)

moles methane used = (30008.35 kJ) / (802.5 kJ/mol)

So the moles methane used = 37.39 mol

Now the mass methane = (moles methane used) * (molar mass methane)

The mass methane = (37.39 mol) * (16.04 g/mol)

The mass methane = 599.74 g

Now the volume methane = (mass methane) / (density of methane)

volume methane = (599.7356 g) / (0.660 g/L)

volume methane = 908.69 L

hope helped!!

plz mark brainliest:DD

The volume of natural gas needed to boil the water if only 17.9% of the heat is generated towards heating water is ; 918.70 L

Using the given data :

Volume of water = 16.5 L = 16500 mL

mass of water = 16500 g  ( 16500 mL * 1.00 g/mL )

Density of methane = 0.668 g/L

Density of water = 1.00 g/mL

First step : determine the heat needed to boil the water

Heat required = mass of water * specific heat water * ( Δ T )

                        = 16500 * 4.184 * ( 100 - 20.4 ) =  5495265.6 J

                        = 5495.265 kJ

∴ Heat required to boil water = 5495.265 kJ

next step ; determine the heat given by combustion

heat given by combustion = ( Heat required to boil water) / ( % of heat generated )

Heat given by combustion = ( 5495.265 ) / ( 17.9 % )

                                             = 30699.80 kJ

Enthalpy of methane combustion = 802.5 kJ/mol

∴ moles of methane used = ( 30699.80 ) / ( 802.5 ) = 38.26 mol

next ; determine the mass of methane ( natural gas )

= ( moles of methane used ) * ( molar mass )

= 38.26 * 16.04 g/mol = 613.69 g

Final step : Calculate the volume of natural gas is needed to boil the water

= mass of natural gas / density of methane

= 613.69 g / 0.668 g/L

= 918.70 L

Hence we can conclude that the volume of natural gas needed to boil water if only 17.9% of the heat is  918.70 L .

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Answer:

K and ba

Explanation:

Answer: K and Ba

Explanation:

Answer:

See Explanation (X and Z)

Explanation:

The question has missing details as the attachment that illustrates the graph is missing.

I'll answer this question using the attached.

Kinetic energy increases as height decreases

Base on the attachment, from order of highest height to the least, we have:

W

Y

Z

X

So, we can conclude that X has the highest kinetic energy and it is immediately followed by Z

Hence:

X and Z answers the question

Answer:

The structure of the atom

Answer:

45727g

Explanation:

So, have the overall ionic equation given as the following;

CrO42^- + 3 Fe2^+ + 8 H2O ------> Cr(OH)^3(s) + 3 Fe(OH)^3(s) + 4 H^+.

So, we have (from the question) that the amount or quantity of the waste stream daily = 60m^3/h, and the waste stream daily contains waste stream containing = 4.0 mg/L Cr, and the discharge limit = 0.1 mg/L.

Step one: convert m^3/ h to L/h. Therefore, 60 m^3/h × 1000dm^3 = 60000 L/h .

Step two: Determine or calculate the the value of Cr used up.

The value of Car used up ={ 60,000 × ( 4.0 - 0.1) } ÷ 1000 = 234 g.

Step three: Determine or calculate the mass of Cr(OH)3 and the mass of Fe(OH)3.

The number of moles of Cr = 234/52 = 4.5 moles.

Molar mass of Cr(OH)3 = 103 g/mol and the molar mass of Fe(OH)3 = 106.8 g/mol.

Thus, the mass of Cr(OH)3 = 4.5 × 103 = 463.5 g.

And the mass of Fe(OH)3 = 13.5 × 106.8 = 1441.8 g.

Hence, the total = 463.5 g + 1441.8 g = 1905.3 g.

Step four: Determine or calculate the How much particulate matter would be generated daily.

The amount of the particulate that would be generated daily = 24 × 1905.3 = 45727g.

Answer: The percent yield of this combination reaction is 41.3 %

Explanation : Given,

Mass of [tex]Na[/tex] = 5.0 g

Mass of [tex]Cl_2[/tex] = 10.0 g

Molar mass of [tex]Na[/tex] = 23 g/mol

Molar mass of [tex]Cl_2[/tex] = 71 g/mol

First we have to calculate the moles of [tex]Na[/tex] and [tex]Cl_2[/tex].

[tex]\text{Moles of }Na=\frac{\text{Given mass }Na}{\text{Molar mass }Na}[/tex]

[tex]\text{Moles of }Na=\frac{5.0g}{23g/mol}=0.217mol[/tex]

and,

[tex]\text{Moles of }Cl_2=\frac{\text{Given mass }Cl_2}{\text{Molar mass }Cl_2}[/tex]

[tex]\text{Moles of }Cl_2=\frac{10.0g}{71g/mol}=0.141mol[/tex]

Now we have to calculate the limiting and excess reagent.

The balanced chemical equation will be:

[tex]2Na+Cl_2\rightarrow 2NaCl[/tex]

From the balanced reaction we conclude that

As, 2 mole of [tex]Na[/tex] react with 1 mole of [tex]Cl_2[/tex]

So, 0.217 moles of [tex]Na[/tex] react with [tex]\frac{0.217}{2}=0.108[/tex] moles of [tex]Cl_2[/tex]

From this we conclude that, [tex]Cl_2[/tex] is an excess reagent because the given moles are greater than the required moles and [tex]Na[/tex] is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of [tex]NaCl[/tex]

From the reaction, we conclude that

As, 2 mole of [tex]Na[/tex] react to give 2 mole of [tex]NaCl[/tex]

So, 0.217 mole of [tex]HCl[/tex] react to give 0.217 mole of [tex]NaCl[/tex]

Now we have to calculate the mass of [tex]NaCl[/tex]

[tex]\text{ Mass of }NaCl=\text{ Moles of }NaCl\times \text{ Molar mass of }NaCl[/tex]

Molar mass of [tex]NaCl[/tex] = 58.5 g/mole

[tex]\text{ Mass of }NaCl=(0.217moles)\times (58.5g/mole)=12.7g[/tex]

Now we have to calculate the percent yield of this reaction.

Percent yield = [tex]\frac{\text{Actual yield}}{\text{Theoretical yield}}\times 100[/tex]

Actual yield = 5.24 g

Theoretical yield = 12.7 g

Percent yield = [tex]\frac{5.24g}{12.7g}\times 100[/tex]

Percent yield = 41.3 %

Therefore, the percent yield of this combination reaction is 41.3 %

Answer:

Explanation:

The mass of a substance when given the density and volume can be found by using the formula

From the question we have

mass = 0.79 × 589

We have the final answer as

Hope this helps you

Answer:

1.b. distillation

2.d. evaporation

3.f. chromatography

4.c. decantation

5.a. filtration

6.e. centrifugation

Explanation:

1. Distillation is the process in which a homogenous mixture of liquid is separated on the basis of difference in boiling points of the substances.

2. Evaporation is the process in which water is converted into gas or vapor based on the boiling point of water or solid.

3. Chromatography is defined as the process used to pure substances from a mixture based on the flow rate of the fluid. The fluid mixture to be separated is called the mobile phase that flows on a stationary phase.

4. Decantation is defined as the process that separates mixtures in which water is poured off the substance to be separated or over solid.

5. Filtration is a separation process in which solids can be separated from liquids by pouring the mixture over a porous barrier.

6. Centrifugation is defined as the separation process that separates heterogeneous substances on the basis of densities in which centripetal acceleration allows substance with high density to move outward in the radial direction.

Answer:

BORON

Ionization energy decreases down the group and going from left to right the period,

Luckily you have the elements from the same group that is Group III A also called boron family,

The position of Elements in this group are

so keeping rules in mind the first element in the group has highest I.E. that is boron