A runner completes a 400m race in 43.9s. What is his average speed?

Answer:

Im not sure because you might have spelled a word wrong.But i believe because of their certain treaditions,belifs,and ways.

Explanation:

The description which explains how pollen is received is that the stigma at the top of the pistil receives pollen and is therefore denoted as option B.

This is a powdery substance produced by seed plants and it consists of one or more vegetative cells and a reproductive cell. It is involved in the production of the male gametes in plants which makes it an importgant component in the ecosystem.

During pollination by different types of agents such as birds, wind etc the pollen are dispersed in various directions in which some get to the stigma at the top of the pistil which is the female reproductive part of the plant.

This therefore leads to fertilization and a fruit is formed as a result which is therefore the reason why option B was chosen as the correct answer.

Read more about Pollen here https://brainly.com/question/21021623

#SPJ1

Answer:

Diaphragm (a muscle)

Explanation:

the diaphragm moves the allows for more opening as it contracts down. It would most likely be the muacular system since the diaphragm is a muscle.

Answer:

J. Their momentum is conserved

Explanation:

According to the diagram, the best statement that describes what happens when two astronauts collides in space is that their momentum is conserved.

The momentum before collision is 320kgkm/hr and after collision it is 320kgm/s

 This collision is an inelastic collision;

    momentum before  = momentum after

              m₁v₁ + m₂v₂     =       v(m₁ + m₂)

m₁ = 80kg

v₁  = 4km/hr

m₂ = 80kg

v₂  = 0

v  = 2km/hr

 Insert the parameters;

              (80 x 4) + (80 x 0)    = 2(80 + 80)

                    320                      = 320

Ion-dipole intermolecular forces of attraction is present between a sodium cation and chloromethane molecule.

The different types of intermolecular forces of attraction are London dispersion forces (LDF), ion-ion, ion-dipole, dipole-dipole, and hydrogen bonding. Molecules could have a mixture of these kinds of intermolecular forces.

Chloromethane, CH3Cl, is considered to be slightly polar due to the carbon-chlorine bond, wherein the chlorine is slightly negative due to its higher electronegativity compared to carbon. With this, the dominant intermolecular forces between CH3Cl are dipole-dipole forces. If a sodium cation is added to the solution, then there would be ion-dipole intermolecular forces of attraction.

To learn more about intermolecular forces of attraction, please refer to https://brainly.com/question/13588164.

#SPJ4

Answer:

T° freezing solution = -22.8°C

Explanation:

To solve this problem we apply, the Freezing Point Depression. This is a colligative property which its formula is:

T° freezing pure solvent - T° freezing solution = Kf . molality . i

i = Van't Hoff factor.

We have been informed is a nonionizing solute, so i = 1

Our solute is ethylene glycol, so le'ts determine the moles to get molality

388 g . 1 mol / 62.07 g = 6.25 moles

molality (m) = moles of solute /kg of solvent

We convert mass of solvent, water, to kg → 510 g . 1kg /1000g = 0.510 kg

6.25 mol /0.510kg = 12.25 m

We replace at formula → 0°C - T° freezing solution = 1.86°C/m . 12.25 m . 1

T° freezing solution = -22.8°C

The second law of thermodynamics states that the total entropy of an isolated system always increases over time. Life doesn't violate the second law of thermodynamics because it is not an isolated system.

It interacts with its environment, which allows it to decrease its own entropy while increasing the entropy of its surroundings.Explanation:Life is a self-organizing system that must consume energy and reduce entropy to maintain its organization. Organisms consume energy in the form of food and sunlight, breaking down the energy-rich molecules they contain and using the resulting energy to power their metabolic processes.

During these processes, some of the energy is lost as heat, increasing the entropy of the system.However, life can also create order and decrease entropy by organizing matter into complex structures and maintaining them. This requires a continuous input of energy to sustain the system.

Therefore, the apparent violation of the second law of thermodynamics by living organisms is merely an illusion because life is not a closed system, and it is constantly interacting with its environment to maintain its organization while increasing the entropy of its surroundings.

To know more about second law of thermodynamics visit:

https://brainly.com/question/7206767

#SPJ11

The name of the formula BF2 is : C.) Boron difluoride. The number of atoms of each element in a compound is known by chemical formula.

Chemical formula is an expression that shows elements in a compound and relative proportions of those elements. If only one atom of specific type is present, then no subscript is used. For atoms that have two or more of a specific type of atom present, then a subscript is written after the symbol for that atom.

Chemical formula contains the symbols of atoms of the elements present in the compound and also how many there are for each element in the form of subscripts.

To know more about chemical formula, refer

https://brainly.com/question/2778716

#SPJ1

Answer:remove 4 electrons

Explanation:

I took the test just a minute a go

The coefficient of variation is a measure of the percent relative standard deviation, which is the ratio of the standard deviation to the mean. The spread or range is the numerical difference between the highest and lowest value in a set of replicate data.

A Gaussian (normal) distribution is a bell-shaped curve obtained by plotting frequency versus deviation from the mean. Significant figures is the term used to describe all the digits in a number that are known with certainty plus the first uncertain digit.

In summary, the coefficient of variation is a measure of the percent relative standard deviation. The spread or range is determined by the numerical difference between the highest and lowest value in a set of replicate data.

The Gaussian (normal) distribution is a bell-shaped curve obtained by plotting frequency versus deviation from the mean. Lastly, significant figures are all the digits in a number that are known with certainty plus the first uncertain digit.

Know more about standard deviation here

https://brainly.com/question/23907081#

#SPJ11

Answer:

yy

Explanation:

Lithium carbonate contains 18.78% mass percent lithium. It should be noted that a compound's overall percentage composition of all its constituent elements is always 100%.

Only depression related to bipolar illness is authorized for lithium use. When combined with an antidepressant, it may also be successful in alleviating other types of depression, although further research is required. Discuss the possibility of adding lithium with your doctor if you are on an antidepressant but are still experiencing symptoms.

This substance is employed for the treatment of mania and depression (bipolar disorder). By bringing certain natural compounds back into equilibrium in the brain, it helps to calm mood and lessen excessive behavior.

To know more about Lithium Carbonate visit:

https://brainly.com/question/15127937

#SPJ1

They are just different ways of drawing the same compound, the following pair are diastereomers.

The given pair of compounds are not constitutional isomers, because constitutional isomers have the same molecular formula but different bond connectivity. But the given pair have the same bond connectivity.

The given pair of compounds are stereoisomers because they have the same molecular formula but the 3D space arrangement is different. And finally, the given compounds are not mirroring images of each other so we call them diastereomers, not enantiomers. As enantiomers are superimposable mirror images of each other. The structures of the given pair of compounds are attached as a picture.

You can also learn about diastereomers from the following question:

https://brainly.com/question/21506956

#SPJ4

The binding of two molecules is typically associated with: (d) An increase in energy and an increase in enthalpy.

The binding of two molecules usually requires an input of energy to overcome the attractive forces between the molecules and bring them closer together. This increase in energy is associated with an increase in the enthalpy of the system. The enthalpy change is positive because energy is being added to the system.

It is important to note that the process of binding can be exothermic or endothermic, depending on the specific molecules and their interactions. However, in general, the binding of two molecules involves an increase in energy and an increase in enthalpy.

Therefore, the correct answer is: d. An increase in energy and an increase in enthalpy.

To know more about the enthalpy change refer here,

https://brainly.com/question/29556033#

#SPJ11

Complete question :

The binding of two molecules is typically associated with: a. An increase in energy and a lowering of enthalpy b. A release of heat energy and an increase in enthalpy c. A release of heat energy and a decrease in enthalpy d. An increase in energy and an increase in enthalpy a

If water vapor constitutes 3.5 percent of an air parcel whose total pressure is 1,000 mb, the water vapor pressure would be 35 mb. The correct option is b.

To calculate the water vapor pressure, we need to determine the partial pressure of water vapor in the air parcel. Given that water vapor constitutes 3.5 percent of the air parcel, we can calculate the partial pressure as follows:

Partial pressure of water vapor = Percent of water vapor × Total pressure

In this case, the percent of water vapor is 3.5 percent, which can be expressed as a decimal fraction of 0.035. The total pressure is given as 1,000 mb.

Partial pressure of water vapor = 0.035 × 1,000 mb = 35 mb

Therefore, the water vapor pressure is 35 mb. Option (b) is the correct answer.

To know more about water vapor refer here:

https://brainly.com/question/30780506#

#SPJ11

Answer:

263.1 is exactly three half-life, so the remaining portion is (1/2 x 1/2 x 1/2) of the original sample. That's 1/8 which is 12.5%

Answer:

12.5 87.5

Explanation:

A tray column with 167 trays should be used for the separation of the methanol and ethanol mixture to achieve at least 95% purity.

The type of column that should be used for separation is a tray column, and the number of trays required can be determined based on the given spacing between trays and the height of the transfer unit.

In distillation processes, the choice between a tray column and a packed column depends on various factors such as the desired separation efficiency, pressure drop limitations, and the nature of the mixture being separated.

In this case, a tray column is selected for the separation of the methanol and ethanol mixture. Tray columns provide efficient separation and are suitable for high purity requirements. The given requirement of achieving at least 95% purity suggests the need for a column with good separation capabilities.

To determine the number of trays required, we can use the height of the transfer unit and the spacing between trays. The height of the transfer unit represents the distance over which the vapor and liquid phases equilibrate, and it is a measure of separation efficiency. The spacing between trays provides the physical distance between each equilibrium stage in the column.

By dividing the height of the column (100 kmol/hr) by the height of the transfer unit (1.0 m), we can determine the number of theoretical stages required for separation. Similarly, dividing the height of the column by the spacing between trays (0.6 m) gives the number of trays required.

These calculations will help determine the appropriate number of trays needed in the column to achieve the desired separation efficiency.

To calculate the number of trays required for the separation, we can use the following formulas:

Number of theoretical stages (N) = Height of column (H) / Height of transfer unit (HTU)

Number of trays (T) = Height of column (H) / Spacing between trays (ST)

Given:

Height of transfer unit (HTU) = 1.0 m

Spacing between trays (ST) = 0.6 m

Height of column (H) = 100 kmol/hr

Calculating the number of theoretical stages:

N = H / HTU

N = 100 kmol/hr / 1.0 m

N = 100 kmol/hr

Calculating the number of trays:

T = H / ST

T = 100 kmol/hr / 0.6 m

T ≈ 166.67 trays

Since the number of trays should be a whole number, we round up to the nearest integer. Therefore, the required number of trays for the separation is 167 trays.

Based on these calculations, a tray column with 167 trays should be used for the separation of the methanol and ethanol mixture to achieve at least 95% purity.

To learn more about separation efficiency, here

https://brainly.com/question/32561734

#SPJ4

ANSWER

option A and B

EXPLANATION

An increase in temperature will increase the average kinetic energy of the molecule, thereby increasing the frequency of collision.

The correct answer are option A and B

The  moles of Ag formed from 91.8 moles of calcium and 41.2 moles of silver nitrate. The balanced formula: Ca(NO3)2 + 2AgCl = 2AgNO3 + CaCl2.

In the balanced equation, the reaction between 2 moles of AgNO3 and CaCl2 yields 2 moles of AgCl.

AgNO3 and AgCl have a molar ratio of 1:1.

The amount of AgCl generated is 18 moles if there are 18 moles of AgNO3 for the reaction with CaCl2.

In this case  41.2 moles of silver nitrate will give,

41.2 ×2

= 82.4 moles of Ag

In the International System of Units, a substance's amount is measured in moles, which are denoted by the sign mol. The quantity of a substance is a measurement of the number of elementary entities of a specific substance present in an object or sample.

For more information on moles kindly visit to

https://brainly.com/question/20486415

#SPJ4



Answer:

Explanation:

approx 30%

Reaction

C₃H₄ + 4O₂ → 3CO₂ + 2H₂O

20% purity = 20% x 200 = 40 g

mole C₃H₄ = mass : molar mass = 40 : 40 g/mole = 1

mole H₂O from reaction coefficient (C₃H₄ limiting reactant) = 2/1 x 1 mole = 2 mole

mass H₂O = mole x molar mass = 2 x 18 g/mole = 36 g

for 60% yield, H₂O produced  = 60% x 36 g = 21.6 g

Answer:

true

Explanation:

energy is the energy to do things

and there is a force in our bodies wich is giving out energy through a distance

Answer:

It plays the role of a catalyst.

Answer:

the law of definite proportion states that in a compound the ratio of atom is fixed

for example, hydrogen and oxygen in pure water is always 1:8 by weight

Mole ratio is the conversion factor used to convert from moles of substance A to moles of substance B (option C).

Mole ratio is a ratio of the number of moles of one substance to the number of moles of another substance in a balanced chemical equation.

It allows us to convert between moles of different substances involved in a chemical reaction. Molar mass (A), Avogadro's number (B), and the mass of 1 mole (D) can be used to convert between moles and other units, such as mass and number of particles.

Learn about Mole ratio here https://brainly.com/question/30632038

#SPJ1

Due of their propensity to create ionic connections by giving up electrons, group 2 elements all share this trait. option (d) is correct.

The negatively charged particles known as electrons revolve around the outer edges of the nucleus. For scientists, it can be challenging to monitor them because of how quickly they spin. The tiniest particles in an atom, you can put 20,000 of them inside a proton, they are drawn to the positive ion of the protons.

Same-group electrons have similar chemcial and physical characteristics. Group-2 is the alkaline earth metals which have tendency to lose two electrons to form the M+2 types of metal ions as after losing two electrons they get the Noble gas configuration.

Since they tend to lose electrons therefore they will form ionic bond with non-metals and results to form the ionic compounds.

To know more about Electrons visit :

https://brainly.com/question/5365825

#SPJ4

The Complete Question :

what do all group 2 elements have in common? (2 points) group of answer choices

(a) they all gain two electrons to form a stable outer energy level.

(b) they form covalent bonds with halogens.

(c) they all react easily with the noble gases

(d) they tend to form ionic bonds by losing electrons.

Due of their propensity to create ionic connections by giving up electrons, group 2 elements all share this trait.

Thus, they tend to form ionic bonds by losing electrons, this is the correct option.

The negatively charged particles known as electrons revolve around the outer edges of the nucleus. For scientists, it can be challenging to monitor them because of how quickly they spin. The tiniest particles in an atom, you can put 20,000 of them inside a proton, they are drawn to the positive ion of the protons.

Same-group electrons have similar chemical and physical characteristics. Group-2 is the alkaline earth metals which have tendency to lose two electrons to form the M+2 types of metal ions as after losing two electrons they get the Noble gas configuration.

Since they tend to lose electrons therefore they will form ionic bond with non-metals and results to form the ionic compounds.

To know more about electrons refer to:

brainly.com/question/5365825

#SPJ4

Answer:

salt

Explanation:

cause salt is a solid item

Answer:

4202.1 K

Explanation:

From;

PV=nRT

P= pressure of the gas = 18.5 bar

V = volume of the gas = 115L

n= number of moles of the gas =  6.1 mole

T= temperature of the gas = ?

R = gas constant = 0.083 L⋅bar⋅K−1⋅mol−1

T = PV/nR

T = 18.5 * 115/6.1 * 0.083

T = 2127.5/0.5063

T= 4202.1 K

The temperature of the food or beverage during consumption affects the volatiles.

The flavor of food or beverages is influenced by the presence of volatile compounds, which are responsible for the aroma and taste. These volatile compounds are released from the food or beverage and interact with our olfactory receptors, contributing to the overall sensory experience. Temperature plays a crucial role in this process.

When food or beverages are heated, the temperature increase leads to an increase in the volatility of certain compounds. Higher temperatures can cause the evaporation of volatile compounds, releasing them into the air and enhancing the aroma and flavor perception. For example, heating coffee can intensify its aroma due to the increased release of volatile coffee compounds.

On the other hand, cold temperatures can also affect flavor perception. Lower temperatures can decrease the volatility of certain compounds, leading to reduced aroma and flavor intensity. This is why some foods or beverages may taste less flavorful when consumed cold compared to when they are warm.

In summary, the temperature of the food or beverage during consumption affects the volatility of compounds, which in turn impacts the flavor perception. Controlling the temperature can play a significant role in enhancing or diminishing the sensory experience of the food or beverage.

Learn more about Temperature from this link:

https://brainly.com/question/7510619

#SPJ11

Answer:

2.54kpa

Explanation:

p*v/t = constant

6.58/539=p2/2111

p2=211(6.50/539)

Answer:

2.53kpa

Explanation:

p1*v1/t1 = constant

the constant can be changed to p2*v2/t2

v2 can be removed from equation as it is constant