The half-life of 90Sr is 29 years. What fraction of the atoms in a sample of 90Sr would remain 175 years later

Answer:

Bacteria decompose rotting plant animal material.

Explanation:

Theres good bacteria, and theres bad bacteria. some helps, and some makes things worse. so really, in some sense all of the above.

Hope that helps.

Bacteria are necessary for life because they help produce oxygen for plants and animals. Similarly bacteria decompose rotting plant and animal materials.

Bacteria are a type of organism which are classified as a kingdom of life. Bacteria are prokaryotic microbes that can spread diseases in animals and plants.

Some of the bacteria are very useful in for our life. Some of them are autotrophs thus, produce energy and oxygen. For example cyanobacteria release oxygen which is used animals and plants to respire.

Bacteria are very essential to degrade wastes and remove them from the  surface. They consume the decomposing plants and animals and make them biodegradable. Some bacteria living in plants helps in nitrogen cycle as well.

Find more on significance of bacteria:

https://brainly.com/question/14225790

#SPJ2

The flask A, flask B, flask C, all have equal average kinetic energy at 0°C.

The average kinetic energy of the particles in a gas is inversely related to its temperature. These particles must move more quickly as the gas warms because their mass is constant.

KE avg = 3/2RT

As a result, it is possible to state that average kinetic energy depends on temperature. As a result, as the temperature rises, the gas molecules become more energetic and move at a faster rate.

The average kinetic energy also stays the same because, in accordance with the question, the temperature is constant across all flasks.

Therefore, the average kinetic energy of flasks A, B, and C at 0°C is the same.

To know more about kinetic energy visit:

https://brainly.com/question/28207341

#SPJ4

Complete question is " Consider three identical flasks with different gases:

Flask A: CO at 760 torr and 273 K

Flask B: N₂ at 250 torr and 273 K

Flask C: H₂ at 100 torr and 273 K

In which flask will the molecules have the greatest average kinetic energy per mole?

Answer:

A.) They would have to prey on other organisms

Explanation:

The answers are.....

Animals that prey on rabbits would begin to prey on other organisms.

And...

Animals that prey on rabbits would starve.

And...

Animals that prey on rabbits would leave the area in search of more rabbits.

My son attends K12 and had this question on his unit 5 test. These were his answer choices and they were correct.

Answer:

The answer is A. a wave of vibrating electric and magnetic energy.

Answer:

T = 3.75 K

Explanation:

As we know

PV = nRT

R =8.3144598 J. mol-1. K-1

P = 0.562 atm

V = 83.3 mL

moles in 0.392 g of I2 = 0.392/mass of I2 = 0.392 grams/253.8089 g/mol = 0.0015 moles

Substituting the given values, we get

0.562 atm * 83.3 *10^-3 L = 0.0015 moles * 8.3144598 J. mol-1. K-1 * T

T = 3.75 K

Answer:

See explanation

Explanation:

Barium sulphate is easily prepared by means of a double replacement reaction. A double replacement reaction is one in which the ions in each of the reactants exchange partners in the products.

For instance, we can decide to prepare barium sulphate by a double replacement reaction between sodium sulphate and barium chloride. The both starting materials are soluble compounds. However, the barium sulphate formed is an insoluble white precipitate. The precipitate is recovered by filtration, washed and dried.

The reaction equation is shown below;

Na2SO4(aq) + BaCl2(aq)  -------> BaSO4(s) + 2NaCl(aq)

Answer:

Ammonium dichromate is an inorganic compound with the formula (NH4)2Cr2O7. In this compound, as in all chromates and dichromates, chromium is in a +6 oxidation state, commonly known as hexavalent chromium. It is a salt consisting of ammonium ions and dichromate ions.

the particular gas effusion was 21.0. and the methane effusion rate is 47.0 The molar mass of the unknown gas is approximately 28.6 g/mol

The process through which a gas manages to escape through with a small hole or highly permeable barrier is known as effusion. A gas's rate of effusion is inversely proportional to its molar mass squared. The following equation describes this relationship: rate1 / rate2 = (sqrt(molar mass2) / sqrt(molar mass1)). where rate1 and rate2 are the rates of effusion of the two gases and molar mass1 and molar mass2 are the molar masses of the two gases.Given the rate of effusion of the unknown gas is 21.0 mL/min, and the rate of effusion of pure methane (CH4) is 47.0 mL/min, we can use the above equation to find the molar mass of the unknown gas:

(21.0 mL/min) / (47.0 mL/min) = sqrt(molar mass unknown) / sqrt(16.04 g/mol)

Squaring both sides of the equation, we get:

(21.0 mL/min)^2 / (47.0 mL/min)^2 = (molar mass unknown) / (16.04 g/mol)

Solving for molar mass unknown we get:

molar mass unknown = (16.04 g/mol) * (21.0 mL/min)^2 / (47.0 mL/min)^2

The molar mass of the unknown gas is approximately 28.6 g/mol

Please note that the above calculation is based on the assumption that the temperature and pressure are the same for both gases and that the gases are ideal

Lear more about effusion here:

https://brainly.com/question/2655041

#SPJ4

Answer: I believe it would be using group input to discuss and prepare preliminary designs

Explanation:

a) The balanced equation is :

C₂H₆   +  Cl₂ --->  C₂H₅Cl  + HCl

b) The percent yield is the 83.0 % %.

a) The balanced equation  is given below :

C₂H₆   +  Cl₂ --->  C₂H₅Cl  + HCl

b) mass of the ethane = 300 g

molar mass of the ethane = 30 g/mol

moles of the ethane = 300 / 30

                                  = 10 mol

mass of chlorine = 650 g

molar mass of the chlorine = 71 g /mol

moles = 650 / 71

          = 9.15 mol

it is clear the the chlorine is the limiting reactant.

1 mole of the chlorine produces the 1 mole of the C₂H₅Cl

moles of the C₂H₅Cl = 9.15 mol

mass of the C₂H₅Cl = 9.15 × 64.5

                                  = 590.175 g

The percent yield = (experimental yield / theoretical yield )  × 100 %

                              = ( 490 / 590 .175 ) × 100 %

                              = 83.0 %

To learn more about percent yield here

https://brainly.com/question/13068053

#SPJ4

The goal of the light reaction is to make NADH an high energy electron transporter and ATP an energy storing molecule.

The energy storage molecule ATP and the reduced electron carrier NADPH are produced by the light-dependent processes using light energy, which is required for the subsequent stage of photosynthesis. Light reactions in plants occur in the thylakoid membranes of organelles referred to as chloroplasts.

The light reactions are largely controlled by photosystems, sizable complexes of proteins and pigments (light-absorbing molecules) that are designed to capture light. Photosystem I (PSI) and Photosystem II are the two different types of photosystems (PSII).

Both photosystems have a variety of pigments that aid in the absorption of light energy as well as a unique pair of chlorophyll molecules at the reaction center. P700 denotes the special pair of photosystem I, while P600 denotes the unique pair of photosystem II.

Learn more about light reaction

brainly.com/question/13349357

#SPJ4

We burn the things that have previously grown in the sunlight-carbohydrates. Hydrogen in the carbohydrates burns to form water which is very harmless. The carbon can be recycled into many different compounds.

The carbon in this material becomes carbon monoxide  carbon dioxide, (Poisonous to us mammals) and the carbon or char which can be a nutrient into the soil. Other things that can be burning in the waste will be toxic. Plants will absorb some  worst things that humans will spill out so carelessly like: lead, cadmium, and the other toxic metals—and these toxins are very dangerous in the atmosphere

So we can indeed to alter the composition of our atmosphere by burning things. Once our planet had a carbon dioxide in the atmosphere. It was a hell-hole here. It was very hot and the atmosphere was poisonous to higher life forms. Gradually life on the planet primarily plant life has been changed this atmosphere into something clean and wonderful. But we by our careless behaviour could return it into its original poisonous luckily the huge coniferous forests clean our air of carbon and the other pollution. We are eroding one factor of this margin after the another. Glaciation, wetlands, oceans, coral reefs, wild areas—these are our safeguards and one after another they are being lost.

--The given question is incomplete, the complete question is

"Explain how the following two processes alter the percentage of carbon dioxide in the atmosphere. I. Combustion (3) II. Respiration (3)".

To know more about carbohydrates here

https://brainly.com/question/29775112

#SPJ4

According to the Boyle's law, the final pressure of gas in cylinder is 3 atmospheres.

Boyle's law is  defined as an experimental gas law which describes how the pressure of the gas decreases as the volume increases. It's statement can be stated as, the absolute pressure which is exerted by a given mass of an ideal gas is inversely proportional to its volume provided temperature and amount of gas remains unchanged.

Mathematically, it can be stated as,

P∝1/V or PV=K. The equation states that the product  of pressure and volume is constant for a given mass or amount  of gas and the equation holds true as long as temperature is maintained constant or does not change.

According to the equation the unknown pressure and volume of any one gas can be determined if two gases are to taken in  consideration.That is,

P₁V₁=P₂V₂

∴P₂=0.8×450/120=3 L.

Learn more about Boyle's law,here:

https://brainly.com/question/1437490

#SPJ2

Answer:

This is true. A seismograph measures the size of a volcano eruption by detecting the vibrations that are produced by the volcanic activity. The vibrations can then be converted into a numerical value that represents the magnitude of the eruption.

Explanation:

Determine the substance's molecular weight in units of one mole, then divide the molar mass value by the molecular mass, and multiply the result by the Avogadro constant to get the required number of molecules.

It is possible to determine the number of molecules by using the relationship between the number of moles and Avogadro's number, which is provided by;

1 mole = Avogadro's constant (NA)

The number of molecules will equal the product of the number of moles and Avogadro's number, which is determined after the number of moles has been determined

To know more about molecules click here

https://brainly.com/question/19922822

#SPJ4

The volume of gas produced by six tablets would be twice the volume produced by three tablets, or 600 cm³ x 2 = 1200 cm³.

Until they are enclosed in a container, gases lack a definite shape or volume. Gases can expand and contract as they are forced into various container sizes and shapes because of the way their molecules spread out and move randomly.

The volume of the container in which a gas is contained can be used to define the volume of the gas itself.

The volume of a gas reduces as the molecules are crammed closer together when it is compressed. A gas's volume rises when it expands.

To know more about volume of gas visit: https://brainly.com/question/12357202

#SPJ4

Answer:

1200 cm³.

Explanation:

At an altitude of 18,000 feet, where the atmospheric pressure is 0.5 atm, the pressure is 7.5 pounds per square inch.

One square inch of any surface has 15 pounds of air sitting on top of it at sea level. That same square inch is only under 7.5 pounds per square inch of pressure at 18,000 feet.

The atmospheric pressure rises with increasing altitude. Contrary to popular belief, the graph shows that pressure decreases as altitude rises (moving to the right on the graph).

At sea level, the atmospheric pressure is 14 pounds per square inch. If we assume that the altitude is zero, we can see that the pressure is equal to 14 pounds per square inch. The atmospheric pressure rises as the altitude gets closer to sea level.

We observe that the pressure value rises as the altitude gets closer to sea level. As the altitude rises, the atmospheric pressure approaches 14 pounds per square foot. Only when the elevation is 0 miles above sea level does the pressure equal 14 pounds per square inch.

The pressure will therefore be 7.5 pounds per square inch if the air pressure in the atmosphere measures at 18,000 feet or 0.5 atm.

To know more about air pressure visit:

https://brainly.com/question/21656406

#SPJ4

Answer:

The correct answer is - 25.

Explanation:

Given:

Sum of the 3 consecutive odd numbers = 69

solution:

Let’s assume the initial number - 2X+1

Let's say the second number is -‘2X+3’ and

Let's say the largest number is- ‘2X+5’.

Sum of the numbers = 69

(2X+1) + (2X+3) + (2X+5) = 69

6X+9 = 69

6X = 69–9

6X = 60

X = 60/6

X= 10

So, x value would be 10. Putting value of X in 2X+5

= 2(10)+5

=25

= 25 (Answer)

Answer:

10.8 days (3 sig.figs.)

Explanation:

All radioactive decay is 1st order decay defined by the expression A = A₀e^-kt

which is solved for time of decay (t) => t = ln(A/A₀) / -k

A = final weight = 1.0 gram

A₀ = initial weight = 16.0 grams

k = rate constant = 0.693/t(1/2) = 0.693/2.69 days = 0.258 days⁻¹

t = ln(1/16) / -0.258da⁻¹ = (-2.77/-0.258) days = 10.74646792 days (calculator)

≅ 10 days (1 sig. fig. based on given 1 gram mass)

Answer:

Liquid from a solid

Explanation:

Answer:

1) 33

2)47

3)33

Explanation:

The atomic number 33 is the same for both protrons and electrons.

Acceleration represented by the equation = Δv/Δt.

The supplied statement indicates that the compound's molecular formula is (CH)ₙ = CH₆ = C₆H₆

Fuel cells may produce energy, power, and heat using hydrogen. The two industries where hydrogen is now most widely employed are urea manufacturing and petroleum refining, with the developing markets of utilities and transportation.

The lowest half figure ratio of a compound is revealed by the empirical formula for that molecule.

Empirical weight formula: 12 + 1 Equals 13.

Molecular weight = 78

n = Molecular weight/Empirical formula weight

n = 78.12/13

n = 6.00

Molecular formula = (CH)ₙ = CH₆ = C₆H₆

To know more about Hydrogen visit:

https://brainly.com/question/24433860

#SPJ1

Answer:

False

Explanation:

there should be sharing of electrons between two of the atoms to be a covalent bonding. but there is no linkage of electron between them

x has the values (2.14 + √(23.288)) / 9.56 and  (2.14 - √(23.288)) / 9.56.

Quadratic equations are the degree two, one-variable polynomial equations of the form f(x) = ax^2 + bx + c = 0 with a, b, c, and R R and a 0 being the variables. In its most basic form, it is a quadratic equation where "a" denotes the leading coefficient and "c" is the absolute term of f(x). The values of x that satisfy the equation (, ) are the quadratic equation's roots.

Intricate relationships exist between square and quadrangle (another name for rectangle) difficulties and quadratic equations.

The Latin term quadratus, which means square, is where the word "quadratic" originates.

The quadratic formula or factoring can be used to get the solution to the problem 4.78x^2-2.14x-1.60=0.

x = (-b (b^2 - 4ac)) / (2a) where a = 4.78, b = -2.14, and c = -1.60 is the quadratic formula.

Plugging in the values we get:

x = (-(-2.14) ± √((-2.14)^2 - 4(4.78)(-1.60)) ) / (2(4.78))

x = (2.14 ± √(4.6016 + 18.688)) / 9.56

x = (2.14 ± √(23.288)) / 9.56

So the two values of x are:

x = (2.14 + √(23.288)) / 9.56 and x = (2.14 - √(23.288)) / 9.56

To know more about Quadratic equations visit: brainly.com/question/30098550

#SPJ4

Physical properties  such as  mass, weights , density can be common for one or more substances hence cannot be used for identification while magnetism is unique for each substance ,hence used for identification.

Any property which describes the state of a physical system is called as a physical property.Changes in physical properties are used to describe changes between the states. They are often related to as observable properties.

Physical property which can be quantified is a physical quantity. These are also classified further with respect to their directionality. Physical properties are differentiated from chemical properties by the way they determine how a substance behaves in a chemical reaction.

Learn more about physical properties,here:

https://brainly.com/question/18327661

#SPJ1

The specific heat capacity of the gaseous ethanol is less than the specific heat capacity liquid ethanol.

The specific heat capacity is given as :

Q = mc ΔT

where ,

Q = heat

m = mass

c = specific heat capacity

ΔT = temperature change

The heating curve represented the temperature , T in the y axis and the heat added at the x - axis. the slope is given as :

T / Q = 1 / C

T is the temperature and the c is the specific heat capacity.

Thus, the heat capacity of the gaseous ethanol is low as compared to the liquid ethanol.

To learn more about heat capacity here

https://brainly.com/question/14240120

#SPJ4

Answer:

[tex]\boxed {\boxed {\sf B. \ 1.5 *10^{23} \ formula \ units}}[/tex]

Explanation:

1 mole of any substance contains the same number of particles. The particles can vary (atoms, molecules, formula units), but there are always 6.022*10²³ particles. In this case, the particles are formula units of potassium nitrate or KNO₃.

Let's create a ratio.

[tex]\frac {6.022*10^{23} \ formula \ units \ KNO_3}{1 \ mol \ KNO_3}[/tex]

Since we are trying to find the formula units in 0.250 moles, we multiply by that number.

[tex]0.250 \ mol \ KNO_3 *\frac {6.022*10^{23} \ formula \ units \ KNO_3}{1 \ mol \ KNO_3}[/tex]

The units of moles of potassium nitrate cancel.

[tex]0.250 *\frac {6.022*10^{23} \ formula \ units \ KNO_3}{1 }[/tex]

The denominator of 1 can be ignored, so we can make a simple multiplication problem.

[tex]0.250 *{6.022*10^{23} \ formula \ units \ KNO_3}[/tex]

[tex]1.5055 * 10^{23} \ formula \ units \ KNO_3[/tex]

If we round to the nearest tenth, the 0 in the hundredth place tells us to leave the 5 in the tenth place.

[tex]1.5 *10^{23} \ formula \ units \ KNO_3[/tex]

0.250 moles of potassium nitrate is approximately equal to 1.5*10²³ formula units of potassium nitrate and choice B is correct.