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Read the passage and examine the photos. Then, suggest two reasons that scientists think developing pollen grains made vascular plants the most successful plants that live on land.


Passage
These mosses are nonvascular plants that grow closely packed together in moist places. The sperm they produce for sexual reproduction must swim to a nearby plant that has an egg that the sperm may fertilize.
Seed plants, such as these conifers, are vascular plants that live in both moist and dry places. For sexual reproduction, conifers produce pollen grains that contain sperm that cannot swim. Conifers produce massive amounts of pollen grains that can be carried by wind.

Answer:

Explanation:

Titration is

when in a lab someone uses

a small pipe called a

pipette

and

drop by drop

they add chemical B (titrant) to chemical A

until something happens

its done drop by drop to find out what is the exact amount needed to cause a reaction

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Answer:

Sodium bicarbonate and acetic acid reacts to carbon dioxide, water and sodium acetate.

Explanation:

Sodium bicarbonate and acetic acid reacts to carbon dioxide, water and sodium acetate. The solid baking soda was placed in liquid vinegar producing carbon dioxide gas, which is evident because of the formation of bubbles in the foaming mixture.

Elements of boron are not found in nature. It is mixed with borates, kernite, ulexite, colemanite, borax, and boric acid. Boric acids are occasionally present in vulcanic spring fluids.

boron into the air, soil, and water during weathering, boron occurs naturally in the environment. In very small quantities, it may also be present in groundwater.

Through the production of glass, the burning of coal, the melting of copper, and the use of agricultural fertilizers, humans add boron to the environment. Human-added boron concentrations are lower than boron concentrations that occur naturally as a result of weathering.

Although it is unlikely that someone may be exposed to borate dust at work, it is possible to be exposed to borate through the air and drinking water. Consumer goods like laundry detergent and cosmetics might expose you to boron.

Thus Elements of boron are not found in nature. It is mixed with borates, kernite, ulexite, colemanite, borax, and boric acid. Boric acids are occasionally present in vulcanic spring fluids.

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The composition and growth method, which enable the development of BCN films predominating between insulating BN and semimetallic graphite, determine the properties of BCN thin films. The influence of synthesis settings on various BCN characteristics are investigated in this regard.

Van der Waals bonds, of which hydrogen bonding is an example, are crucial to the characteristics of water and to how it behaves in biology. Dipole-dipole interactions with bonds between hydrogen and other atoms are thought to be the cause.

Both inorganic materials like water and biological compounds like DNA and proteins include hydrogen bonding. Van der Waals attractions, which depend on tiny variations in the electron concentrations, can happen between any two or more molecules.

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ANSWER

2Ba + 2HBr → 2BaBr + H2

2BiCl3 + 3H2S → Bi2S3 + 6HCl

Br2 + 2KI → I2 + 2KBr

4Fe + 3O2 → 2Fe2O3

Answer:

\(3Mg _{(s)} + N _{2(g)} → Mg_{3} N _{2(s)}\)

\(Ba _{(s)} + 2HBr_{(g)} → BaBr _{2(s)} + H _{2(g)}\)

\(2BiCl_{3(s)} + 3H_{2} S _{(g)} → Bi _{2} S _{ 3(g)} + 6HCl _{(g)} \\ \)

\(Br_{2(g)} + 2KI _{(g)} → I _{2(g)} +2 KBr _{(g)}\)

\(4Fe_{(s)}+ 3O_{2(g)} → 2Fe_{2} O _{3(s)} \)

Answer:

Pb, Sn, Te, S, Cl

Explanation:

Answer is option B- Oxaloacetate/aspartate is an alpha-keto acid/alpha-amino acid pair used in transamination.

To create the amino acid version of the keto-acid and the keto-acid version of the original amino acid, amino groups are removed from amino acids and transferred to acceptor keto-acids by the process of transamination.

An amino group is transferred from one molecule to another during transamination. The formation of -ketoglutaric acid and aspartic acid from the interaction of glutamic acid and oxaloacetic acid serves as an example of this.

The reversible transfer of an amino group from glutamate to oxaloacetate, which results in the production of aspartate, is physiologically catalyzed by the enzyme AST. The enzyme was therefore previously known as serum glutamic-oxaloacetic transaminase.

Hence, Oxaloacetate/aspartate is an alpha-keto acid/alpha-amino acid pair used in transamination.

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Cations are always smaller than the atoms from which they form. Anions are always larger than the atoms from which they form. Ions are usually bigger than the atoms from which they are formed.

When an atom receives or loses electrons, the atom's electron configuration changes, resulting in a net positive or negative charge.

This net charge expands the electron cloud surrounding the nucleus, making the ion bigger in size than the neutral atoms from which it arose. When a metal atom loses one or more electrons to create a cation, it shrinks in size because the positive charge of the nucleus pulls the remaining electrons more strongly.

When a nonmetal atom obtains one or more electrons to create an anion, it normally expands in size.Because of the increasing amount of electrons, the electron cloud surrounding the nucleus grows. It should be noted that this comparison is not absolute and is dependent on the individual factors involved. Some ions are smaller than their neutral atom counterparts, while others are similar in size.

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The complete question is:

Compare the size of ions to the size of atoms from which they form.

The metric prefixes which is not one multiple of ten when moving forward or backward between prefixes is: none of the above

Option c is the correct answer

A metric prefix simply refers to a unit prefix that precedes a basic unit of measure to indicate a multiple or sub-multiple of the unit.

So therefore, the metric prefixes which is not one multiple of ten when moving forward or backward between prefixes is: none of the above

Complete question:

Which of the following metric prefixes are not one multiple of ten when moving forward or backward between prefixes?

a. micro

b.nano

c. none of the above

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Answer:

Explanation:

To solve this problem, we need to use the balanced chemical equation for the reaction between hydrobromic acid (HBr) and magnesium hydroxide (Mg(OH)2):

2HBr + Mg(OH)2 -> MgBr2 + 2H2O

From the equation, we can see that 2 moles of hydrobromic acid react with 1 mole of magnesium hydroxide.

We are given the volume of the hydrobromic acid as 5.0 mL, but we do not know the number of moles of hydrobromic acid present. However, we do know the concentration and volume of the magnesium hydroxide used for the titration. We can use this information to calculate the number of moles of magnesium hydroxide used in the titration:

Molarity of Mg(OH)2 = 1.50 M

Volume of Mg(OH)2 used = unknown (we don't know how much was added to reach the endpoint)

We can assume that the reaction between the two solutions goes to completion and that all the magnesium hydroxide reacts with the hydrobromic acid present. Therefore, we can set up the following equation using the stoichiometry of the reaction:

2 moles HBr = 1 mole Mg(OH)2

moles of HBr = (moles of Mg(OH)2) / 2

Using the equation for molarity (M = moles / liters), we can calculate the number of moles of magnesium hydroxide used in the titration:

Molarity of Mg(OH)2 = moles of Mg(OH)2 / volume of Mg(OH)2

moles of Mg(OH)2 = Molarity of Mg(OH)2 x volume of Mg(OH)2

We don't know the volume of Mg(OH)2 used, but we can use the volume of hydrobromic acid and the balanced chemical equation to determine it. Since 2 moles of HBr react with 1 mole of Mg(OH)2, we can say that:

moles of Mg(OH)2 = (moles of HBr) / 2

Using the equation for molarity and the given volume of hydrobromic acid (5.0 mL or 0.005 L), we can calculate the number of moles of hydrobromic acid present:

Molarity of HBr = moles of HBr / volume of HBr

moles of HBr = Molarity of HBr x volume of HBr

Now we can combine the equations to solve for the unknown volume of magnesium hydroxide used in the titration:

moles of Mg(OH)2 = (Molarity of Mg(OH)2) x (volume of Mg(OH)2)

moles of HBr = 0.5 x moles of Mg(OH)2 (since 2 moles of HBr react with 1 mole of Mg(OH)2)

moles of HBr = (Molarity of HBr) x (volume of HBr)

Since the moles of HBr are the same in both equations, we can set them equal to each other:

(Molarity of HBr) x (volume of HBr) = 0.5 x (Molarity of Mg(OH)2) x (volume of Mg(OH)2)

Solving for the unknown variable, we get:

(Molarity of HBr) = (0.5 x (Molarity of Mg(OH)2) x (volume of Mg(OH)2)) / (volume of HBr)

(Molarity of HBr) = (0

Answer: A. They were traveling through different types of rocks

Explanation:

Answer:

D

Explanation:

The corrosive sign includes a hand with chemicals dropping onto it.

The flammable sign includes a flame.

The. chemical sign for carcinogenic chemicals is the one above, therefore the answer is D

Answer:

Significant Figures in 200.0

Result 200.0

Sig Figs 4 (200.0)

Decimals 1 (200.0)

Scientific Notation 2.000 × 102

E-Notation 2.000e+2

To slow down the molecules of the medicine and cause a phase change, the doctor needs to transfer energy out of the medicine until it is a solid.

She would expel energy from the medication until it solidified in order to accomplish this. The kinetic energy of the molecules is reduced by removing energy from the medication, usually by cooling or freezing. A phase transition from a liquid to a solid state is caused by this decrease in molecular mobility.

Compared to the more mobile molecules in the liquid phase, the slower-moving molecules in the solid phase will have less mobility to manoeuvre around one another. With the use of this procedure, the doctor is able to regulate the medication's physical state for a number of uses, including patient administration, storage, and preservation.

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An epoxide is a heterocyclic organic compound with an oxygen ring. The acid protonates the oxygen, which opens the ring and starts the process.

What exactly is carbocation?

A carbocation is a molecule with three bonds and a positively charged carbon atom. To put it simply, they are essentially carbon cations. It was previously known as carbonium ion. A carbocation is any even-electron cation having a significant positive charge on the carbon atom.

Because of an incomplete octet, carbon cations are particularly reactive and unstable in general.

To put it simply, carbocations do not meet the octet rule because they lack eight electrons.

According to the question, carbon hybridization in carbocation will be sp2 with a trigonal planar structure. There is also an empty p orbital, suggesting that it is electron-deficient. Carbon contains six electrons in its valence shell. As a result, it is an electron-deficient species, also known as an electrophile.

An epoxide is a heterocyclic organic compound with an oxygen ring. The acid protonates the oxygen, which opens the ring and starts the process. A carbocation is now generated, which is quickly attacked by a water molecule.

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An epoxide is a heterocyclic organic compound with an oxygen ring. The acid protonates the oxygen, which opens the ring and starts the process.

What exactly is carbocation?

A carbocation is a molecule with three bonds and a positively charged carbon atom. To put it simply, they are essentially carbon cations. It was previously known as carbonium ion. A carbocation is any even-electron cation having a significant positive charge on the carbon atom.

An epoxide is a heterocyclic organic compound with an oxygen ring? The acid protonates the oxygen, which opens the ring and starts the process. A carbocation is now generated, which is quickly attacked by a water molecule.

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It is a base because in solution it produces two hydroxide anions.

The Arrhenius theory, proposed in 1887 by the Swedish scientist Svante Arrhenius, states that acids dissociate in water to produce electrically charged atoms or molecules known as ions, one of which is a hydrogen ion (H+), and that bases ionize in water to produce hydroxide ions (OH). Acid, according to the Arrhenius theory, is a substance that releases H+ ions when dissolved in aqueous solution. The concentration of H+ ions in the solution rises. The base is a substance that, when dissolved in aqueous solution, ionizes the OH- ion.

Here,

The same logic holds true for the reaction of sulfuric acid and barium hydroxide. This reaction involves an Arrhenius acid, which generates two hydrogen cations in solution, and an Arrhenius base, which generates two hydroxide anions in solution.

It is a base as it generates two hydroxide anions in solution.

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Answer:

The most abundant isotope is 1.007 amu.

Explanation:

Given data:

Average atomic mass = 1.008 amu

Mass of first isotope = 1.007 amu

Mass of 2nd isotope = 2.014 amu

Most abundant isotope = ?

Solution:

First of all we will set the fraction for both isotopes

X for the isotopes having mass  2.014 amu

1-x for isotopes having mass 1.007 amu

The average atomic mass is 1.008 amu

we will use the following equation,

2.014x + 1.007  (1-x) = 1.008  

2.014x + 1.007  - 1.007 x = 1.008  

2.014x - 1.007x  =  1.008  -  1.007

1.007 x = 0.001

x= 0.001/ 1.007

x= 0.0009

0.0009 × 100 = 0.09 %

0.09 % is abundance of isotope having mass  2.014 amu because we solve the fraction x.

now we will calculate the abundance of second isotope.

(1-x)

1-0.0009 = 0.9991

0.9991 × 100= 99.91%

Wavelength of an EM wave indicates that as the wavelength decreases, the energy increases. option A.

The distance between identical points in adjacent cycles of a waveform signal propagated in space or along a wire is defined as the wavelength. This length is typically specified in wireless systems in meters (m), centimeters (cm), or millimeters (mm) (mm).

The frequency and energy (E) of a wavelength decrease as its size increases. These equations show that as the frequency and energy increases, the wavelength decreases. The wavelength grows longer as the frequency decreases. There are two basic types of waves: mechanical and electromagnetic.

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The calcium ion has 18 protons, 20 neutrons, and 20 electrons.
The relationship between the components a and b is Inverse proportion.


The calcium ion (Ca2+) has a 2+ charge, indicating that it has lost 2 electrons from its neutral state. To determine the number of protons, neutrons, and electrons in the calcium ion, we need to consider its atomic number and mass.

The atomic number of calcium is 20, which indicates that it has 20 protons. Since the calcium ion has a 2+ charge, it means it has lost 2 electrons. Therefore, the number of electrons in the calcium ion is 20 - 2 = 18.

The mass number of calcium is 40 amu, which represents the total number of protons and neutrons. Since the calcium ion has 20 protons, the number of neutrons can be calculated as 40 - 20 = 20.

So, the correct option is: d. 18 protons, 20 neutrons, and 20 electrons

In the expression a∼1/b, the relationship between the components a and b is an inverse proportion. This means that as the value of a increases, the value of b decreases, and vice versa. The symbol ∼ represents the proportional relationship between a and 1/b, indicating that they are inversely related. Therefore, the correct answer is: Inverse proportion

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Answer:

B. PEA = KEC. +PEC

Explanation:

From the figure it is clear that there is interconversion between potential energy ( PE ) and kinetic energy ( KE ) , so that total mechanical energy is conserved .

At A only potential energy exists . Kinetic energy is zero .

At B only kinetic energy exists . Potential energy is zero .

At C both potential and kinetic energy exist .

So Potential energy at A is equal to potential energy at C and kinetic energy at C

Ie , PEA = KEC + PEC .

Option B is correct .

Explanation:

10 moles h20 is required

10 moles of H₂ are required to make 10 moles of H₂O.

Stoichiometry is an important concept which helps us use the balanced chemical equation to measures the amount of reactants and products.

A balanced chemical equation is chemical equation that has equal number of atoms on both sides of arrow that is reactant and product.

First we have to write the Balanced chemical equation

2H₂ + O₂ → 2H₂O

To produce 2 moles of water, 2 moles of hydrogen are required to produce 10 moles of water.

So,

\(\frac{2\ \text{moles of}\ H_2}{2\ \text{moles of}\ H_2O}\) × 10 moles of H₂O

= 10 moles of hydrogen are required.

Thus, from above conclusion we can say that 10 moles of H₂ are required to make 10 moles of H₂O.

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Answer: D 25 degrees

Explanation: The reason because is 25x4=100 and slightly tilted =1/4 of the earth which is 25

Answer:

Solute=the substance which a solvent dissolve to produce homogeneous mixture

Solvent= the substance in which a solute dissolve to produce homogeneous mixture

Explanation:

solvent: The liquid in which a solute is dissolved to form a solution.

solute: The component in a solution, dissolved in the solvent.

Answer:

A push or pull is referred to as a force. Forces can cause objects to move, slow, stop, or change the direction in which they travel. The force of gravity, for example, pulls all objects toward the Earth's center. Every time two things interact, a force is exerted on each of them. When this happens, the two items no longer feel the force after the interaction ends.

Explanation:

Force is that external physical cause which changes or tends to change:

hope this helps you.

Answer:

Chlorine molecules are composed of two atoms (Cl2).

There are four atoms in  two molecules of chlorine as each molecule of chlorine is made up of two atoms.

An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.

The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.

Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.

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4.56g excess reactant is left over when 17.0 g of potassium hydroxide (KOH) reacts with 20.0 g of iron (III) nitrate (Fe(NO₃)₃)

Reactants are raw materials that react with one another and form products.

Here given balanced reaction is

2KOH + Fe(NO₃)₂ → Fe(OH)₂ + 2KNO₃

Then we have to calculated the masses of KOH and Fe(NO₃)₂ from the balanced reaction

Molar mass of KOH = 39+16+1 = 56g/mol

Mass of KOH = 2×56 = 112g

And the molar mass of Fe(NO₃)₂ = 56+2[14+(16×3)]

= 56+2[14 + 48)]

= 56+2[62]

= 56+124

= 180g/mol

Then from the balanced equation

112g of KOH and 180g/mol of  Fe(NO₃)₂

Then the 17 g of KOH = 17×180/112g

= 27.32 g of Fe(NO₃)₂

Then for 20.0 g of iron (III) nitrate

Therefore Xg of KOH = 112×20/180

Xg of KOH = 12.44g

Thus 12.44g of KOH reacted

Therefore we have determine the leftover mass of the excess reactant

Mass of KOH leftover = ?

Mass of KOH leftover = (Mass of KOH given) – (Mass of KOH that reacted)

Mass of KOH leftover = 17 - 12.44g

Mass of KOH leftover = 4.56g

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The units of measurement that can be used for precipitation with mm or inches is precipitation, and air temperature.

The Temperature is known to be how hot or cold the air or atmosphere is. It is often measured by the used of a thermometer (in Celsius (C) or Fahrenheit (F), or Kelvin (K) ).

The unit of measurement for precipitation is said to be in millimeters. The unit is known to be in linear depth, that is in millimeters (for volume/area), or in kg m–2 (for the mass/ area).

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A is air pressure and is a temperature

O A is humidity and precipitation

O A is precipitation, and B is air temperature

O A is wind speed, and B is humidity

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Answer:

Book on Table

Car at the Hilltop

Falling Objects

Skydiver

Hammering a Nail

Dam Water

Roller Coaster

Stretched Rubber Band

Simple Pendulum

Compressed Spring

Battery

Flashlight

Exothermic Chemical Reaction

Burning of Oil, Gas and Coal

Wind Turbine

Explanation:

have a nice day!

Answer:

1. Number 3

2. Number 1

3. Number 5

4. Number 4

5. Number 2

I think, this is the order.