Weather Unit Test
Which statement best describes the air behind a cold front? (1 point)
O The air is warmer and more humid.
O The air is cold and filled with moisture.
O The air is colder and drier.
O The air is warm and dry.

Because of the fact that certain ions and impurities are adsorbed on the precipitate's surface. Precipitate is washed with tap water in order to eliminate these contaminants since water will wash away any pollutants that are still soluble in it.

Ions are electrically charged particles that may be produced by either taking electrons away from neutrality atoms to form positive ions or adding electrons to neutral atom to form negative ions. The quantity of protons remains constant during the creation of an ion.

Negative ions are believed to trigger biochemical processes that enhance serotonin levels once they enter our blood, which helps to reduce depression, reduce stress, and improve energy.

To know more about ions visit:

https://brainly.com/question/29183072

#SPJ1

The right response is option D. All of the above mentioned except xef4 make up the tetrahedral electron-domain shape. The way the electrons are arranged in three dimensional atoms.

Around the primary atom is known as the electron domain geometry. within a molecule. The quantity of electron pairs around the centre atom can be used to calculate the shape of the electron domain. The electron (e or ) is a subatomic particle with an initial electric charge that is negatively one. Due to their lack of known components or substructure, electrons, which are part of the first generation of the lepton particle family, are typically considered to be elementary particles. A nucleus and one or more electrons attached to the nucleus make up every atom.

Learn more about electrons here

https://brainly.com/question/28977387

#SPJ4

The complete question is -

the electron-domain geometry of __________ is tetrahedral.

a. cbr4

b. ph3

c. ccl2br2

d. xef4

e. all of the above except xef4

At a certain temperature, the equilibrium constant for the reaction is 263.16 or 2.6*10^2 and 5.5 * 10^-8.

1. K = ( HCl )^2 / (H2)*(Cl2)

As the value of K is very less so HCl is very less amount and H2 & Cl2.

2. 2HCl = H2 + Cl2  as the reaction is reverse so equilibrium value will be inverse.

K' = 1/K

= 1/ 0.0038

= 263.16 or 2.6*10^2

3.  3H2 + 3 Cl2 = 6 HCl

Reaction is multiplied by 3 so K will be Cube

K' = K^3

= (0.0038)^3

= 5.5 * 10^-8

Equilibrium, in physics, the state of a system when neither its state of motion nor its internal energy state tend to change over time. A simple mechanical body is in equilibrium when it experiences neither linear nor angular acceleration. This state will continue indefinitely unless disturbed by an external force.

Equilibrium occurs for a single particle when the vector sum of all forces acting on the particle is zero. A rigid body (which by definition differs from a particle by its properties of extension), in addition to the states listed above for particles, is in equilibrium when the vector sum of all torques acting on the body is equal to zero, so Its state of rotational motion remains constant.

Learn more about equilibrium here : https://brainly.com/question/517289

#SPJ4

The correct response is A) The change in gaseous moles n g must be largest, indicating the formation of more gaseous products, which enhances unpredictability and, hence, entropy positive.

Entropy increases as a substance transitions from a solid to a liquid to a gas, and by observing the phases of the reactants and products, you can determine if an entropy change is positive or negative. Entropy will rise once the number of gas moles increases. The environment's negative entropy change is significantly outweighed by the system's positive entropy change. We can see that the system's entropy change is positive.

To learn more about positive  please click on below link

https://brainly.com/question/12650352

#SPJ4

A 1.5 g/ml of liquid is present in beaker 1 and 2.0 g/ml of liquid is present in beaker 2. In both beakers, the item sinks. The item has a density of more than 2.0 g/cm³.

a material substance's density is defined as its mass per unit volume. D is density, M is mass, and V is volume, therefore the formula for density is d = M/V. In terms of grammes per cubic centimetre, density is frequently expressed. As an illustration, the density of water is 1 g/cc, whereas the density of the Earth is 5.51 g/cc. As kilos per cubic metre, density can also be calculated (in metre-kilogram-second or SI units). As an illustration, the air has a density of 1.2 kilogrammes per cubic metre. Textbooks and manuals contain lists of the densities of common solids, liquids, and gases. It is simple to determine a body's mass from its volume, or vice versa, using its density.

Learn more about density here:

https://brainly.com/question/17990467

#SPJ4

We need to know the number of moles of each gas in the tank as well as the tank's overall pressure in order to determine the mole fraction and partial pressure of each gas.

Let's say, for illustration, that the tank has a total pressure of 100 atmospheres and contains 10 moles of carbon dioxide and 20 moles of dinitrogen difluoride. The mole fractions of carbon dioxide and dinitrogen difluoride would be 10/(10+20) = 0.33 and 0.67, respectively. Carbon dioxide would have a partial pressure of 0.33 * 100 atms, or 33 atms, while dinitrogen difluoride would have a partial pressure of 0.67 * 100 atms, or 67 atms. As predicted, the tank's overall pressure would be 100 atmospheres.The mole fraction of a gas is the proportion of that gas's moles to the total moles of all the gases in the tank. We can determine the overall pressure in the tank by summing the partial pressures of all the gases once we have the partial pressure and mole fraction of each gas.

to know more about mole please refer:

https://brainly.com/question/26416088

#SPJ4

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, the mass of every substance can be calculated as below.

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.

HNO[tex]_2[/tex] + KOH  [tex]\rightarrow[/tex] KNO[tex]_2[/tex]+ H[tex]_2[/tex]O

The mole ratio among HNO[tex]_2[/tex], KOH, KNO[tex]_2[/tex] and H[tex]_2[/tex]O is 1:1:1:1.

number of moles of HNO[tex]_2[/tex]= given mass of HNO[tex]_2[/tex]/ molar mass of HNO[tex]_2[/tex]

number of moles of HNO[tex]_2[/tex]= 0.87 / 31.01

                                          = 0.028 moles

moles of HNO[tex]_2[/tex], KOH, KNO[tex]_2[/tex] and H[tex]_2[/tex]O is  0.028 moles

mass of KOH= moles of KOH× Molar mass of KOH

                     =  0.02× 56.11

                     =1.12g

mass of  KNO[tex]_2[/tex]=  0.02× 85.1

                        = 1.70g

mass of  H[tex]_2[/tex]O =0.02× 18

                     = 0.36g

Therefore, the mass of every substance can be calculated as above.

To know more about mole, here:

https://brainly.com/question/15209553

#SPJ1

A valid lewis structure of cannot be drawn without violating the octet rule is IF₃.

According to the octet rule the atoms will be more stable if the valence electrons in the valence are eight electrons.

a) NF₃ = in the lewis structure of  NF₃ the atom will contains the eight valence electrons in the valence shell. thus it follows the octet rule.

b) SO₄²⁻ =  SO₄²⁻ , lewis structure follows the octet rule . atoms contains the eight valence electrons.

c) PF₃ = phosphorus valence electrons is 5 and the fluorine valence electron is 7 and fulfil the octet rule.

d) IF₃ = in the lewis structure IF₃  , it does not follows the octet rule . it  contains the more than eight electrons .

To learn more about lewis structure here

https://brainly.com/question/7026917

#SPJ4

Cobalt-60 is radioactive and has a half life of 5.26 years . amount of 3.60 mg sample would be left after 5.20 years is 1.82 mg.

The half-life t1/2 = 5.26 years

the decay constant , k = 0.693 / t1/2

                                      = 0.693 / 5.26

                                      = 0.1317 / year

the expression is given as :

t = 2.303 / k log No/N

No = 3.60 mg

t = 5.20 yr

5.20 = 2.303 / 0.1317 log 3.60 / N

5.20 = 17.4  log 3.60 / N

log 3.60 / N = 0.2988

3.60 / N = 1.989

N = 1.82 mg

The question is incomplete , the complete question is :

cobalt- is radioactive and has a half life of years. how much of a sample would be left after years? round your answer to significant digits. also, be sure your answer has a unit symbol.

To learn more about half-life here

https://brainly.com/question/17461661

#SPJ4

Answer: To determine how many grams of calcium chloride will be produced when 27.0 g of calcium carbonate is combined with 11.0 g of hydrochloric acid, we can use the balanced chemical equation for the reaction:

CaCO3 + 2 HCl -> CaCl2 + H2O + CO2

From the equation, we can see that for every mole of calcium carbonate that reacts, one mole of calcium chloride is produced. We can use the molar masses of each compound to convert the number of grams of each reactant to moles, and then use the mole ratios from the balanced chemical equation to determine the number of moles of calcium chloride produced.

The molar mass of calcium carbonate is 100.09 g/mol, so 27.0 g of calcium carbonate is equal to 0.269 moles. The molar mass of hydrochloric acid is 36.46 g/mol, so 11.0 g of hydrochloric acid is equal to 0.302 moles.

From the balanced chemical equation, we can see that for every mole of calcium carbonate that reacts, two moles of hydrochloric acid are needed. This means that we have an excess of hydrochloric acid, and the limiting reactant in this reaction is calcium carbonate. Therefore, the number of moles of calcium chloride produced will be equal to the number of moles of calcium carbonate consumed, which is 0.269 moles.

To determine the mass of calcium chloride produced, we can multiply the number of moles of calcium chloride by its molar mass. The molar mass of calcium chloride is 110.98 g/mol, so the mass of calcium chloride produced is 0.269 moles * 110.98 g/mol = 29.8 g.

Therefore, when 27.0 g of calcium carbonate is combined with 11.0 g of hydrochloric acid, 29.8 g of calcium chloride will be produced.

Copper is a metal that can behave like a magnet because It is a conductor and can support electric current.

What is a definition of metal?

Strong electrical and thermal conductivity, malleability, ductility, and high light reflection are all characteristics of metals, which are one type of materials.

Copper is not magnetic in and of itself. However, when a magnet comes close to copper (and some other metals), the magnetic field causes the copper's surface electrons to reorganize and start revolving. They generate resistance by rotating in a circular motion perpendicular to the magnetic field.

Copper has the highest conductivity among non-precious metals, which means it can carry more electrical current than other non-precious metals.

To know more about conductivity use link below:

https://brainly.com/question/24943129

#SPJ1

According to the amagats law , the total pressure that is occupied by a gas is a sum of its partial volumes.

We know that the volume of a gas has to do with the space that is being occupied by the gas. This is actually the physical space that has been taken up by the gas.

We know that a gas takes up the entire volume of the container. The volume of the container that is taken up by each of the gasses that can be found in a given mixture of gases is not the same.

As such we can be able to speak of the partial volume of a gas which is the space that the gas is able to take up in a mixture of gasses. This is the fraction of the volume of the container that has been occupied by the particular gas that is in question.

Learn more about amagats law :https://brainly.com/question/15396335

#SPJ1

The mRNA sequence created by the template strand, 3' A T C G G T T A A C 5', and the coding strand, 5' T A G C C A A T T G, will be 3' G U U A A C C G A U 5'.

The strand that is complementary to the mRNA is the lower strand. The transcriptional start site (the A) is marked on the coding strand together with the promoter sequence's -35 region (TTGACA) and -10 region (TATATT).

An individual amino acid is specified by each codon, which are groups of three nucleotides in mRNA.

Learn more about proteins here:

https://brainly.com/question/29776206

#SPJ1

The mass of the oxygen used during the reaction is 8.16 g

The chemical element with the atomic number 8 and symbol O is called oxygen. It belongs to the periodic table's chalcogen group, is a very reactive nonmetal, and an oxidizing agent that easily produces oxides with most elements as well as other compounds.

The reaction is as follows ,

4Fe + 3 ⇒ 2

The molar ratio of the reaction  

= 4:3

The four moles of  Fe react with 3 moles of oxygen molecule to produced Iron Oxide .

The mole of iron = mass ÷ molar mass

= 19.43 g ÷ 55.845 g/mole

= 0.34 mole

If four moles of  Fe react with 3 moles of oxygen molecule to produced  Iron Oxide .

The number of moles of oxygen

= 3 moles × 0.34 mole ÷ 4 moles

= 0.22 mole

The mass

= 0.22 × 32

= 8.16 g

Thus, The mass of the oxygen used during the reaction is 8.16 g

To learn more about the oxygen, follow the link;

https://brainly.com/question/1506082

#SPJ1

Specialized cells called peripheral chemoreceptors in contact with arterial blood react immediately to variations in blood PO2.

Carotid and aortic bodies, which are peripheral chemoreceptors, sense changes in arterial blood oxygen levels and set off reflexes that are crucial for preserving homeostasis in hypoxemia. The carotid (and aortic) bodies, which act as peripheral chemoreceptors, recognise arterial hypoxia and promote breathing. They give the brain stem a constant excitatory input at normal arterial PO2 (PaO2) values (6), and in hypoxia, they react dramatically as PaO2 drops below 70 Torr. With some help from [H+], peripheral chemoreceptors are particularly sensitive to changes in PaO2. The peripheral chemoreceptor hypoxic response predominates in situations where the receptors disagree, such as hypoxic hypocapnia, causing the respiratory drive to increase oxygenation despite additional reductions in CO2.

To learn more about oxygen click here https://brainly.com/question/13370320

#SPJ4

Answer:

the ppb ratio of sulfur atoms is 1/250.

Explanation: i do math for livin cuh

The letter A represents the dispersion forces as a kind of intermolecular force. Option A

We know that a concept map can be regarded as the framework that is used to be able to organize  facts and then be able to pass across an information. Thus a concept map is a tool that helps in the explanation of facts.

Given that we can see from the concept map that the compound is not composed of ions and there are no permanent dipoles that can be seen in the molecule, the simple meaning is that there is no kind of intermolecular interaction that involves the attraction of the oppositely charged ions in the compound and this would correspond to the dispersion forces.

In this kind of dipole attraction, it is the intermittent shifts in the electron cloud that leads to the attraction.

Learn more about concept map:https://brainly.com/question/25646607

#SPJ1

The pH will decrease and goes in acidic sense in the following situations i.e. in the reaction of H2SO4 (aq) + HSO4.

Chemistry uses a scale known as pH, which formerly stood for "potential of hydrogen" (or "power of hydrogen"), to express how acidic or basic an aqueous solution is. Acidic solutions (solutions with higher H+ ion concentrations) have lower pH values than basic or alkaline solutions. The pH scale, which is logarithmic, exhibits an inverse relationship with the concentration of hydrogen ions in the solution. To trace the pH scale, a group of standard solutions whose pH has been established by international agreement can be employed. The potential difference between a hydrogen electrode and a standard electrode, such as the silver chloride electrode, is measured using a concentration cell with transference to obtain the primary pH standard values. The pH of aqueous solutions can be measured using a glass electrode, a pH meter, or a color-changing indicator. pH measurements are important in many fields, including chemistry, agronomy, medicine, water treatment, and many more.

To know more about pH please refer: https://brainly.com/question/28565107

#SPJ4

Answer:160 L of CO₂.

Explanation: Give me brainly please.

The volume of CO₂ absorbed is 0.371 L (or 371 mL) at 3.5 × 10⁻⁴ atm and 295 K.

To calculate the volume of CO₂ absorbed by 6.77 g of Li₂O, we need to use the ideal gas law, which states:

PV = nRT

where P is the pressure, V is the volume, n is the number of moles of gas, R is the ideal gas constant, and T is the temperature in Kelvin.

First, calculate the number of moles of CO₂:

Molar mass of Li₂O = 2 * (6.94 g/mol) + 15.999 g/mol ≈ 29.88 g/mol

Moles of Li₂O = 6.77 g / 29.88 g/mol ≈ 0.2263 mol

Now, we can use the given pressure and temperature:

P = 3.5 × 10⁻⁴ atm

T = 295 K

Rearrange the ideal gas law to solve for V:

V = nRT / P

V = (0.2263 mol) * (0.08206 L atm/mol K) * (295 K) / (3.5 × 10⁻⁴ atm)

V ≈ 0.371 L

So, the volume of CO₂ that 6.77 g of Li₂O can absorb at 3.5 × 10⁻⁴ atm and 295 K is approximately 0.371 L (or 371 mL).

To learn more about  ideal gas law  here

https://brainly.com/question/1409639

#SPJ2

The majority of stable atoms share electrons. When two atoms share electrons, they establish a covalent bond. The result of sharing electrons are molecules, which are neutral particles.

Due to the fact that all orbitals will be filled, an entire octet is exceedingly stable. A process that increases the stability of the atoms will release energy in the form of heat or light because more stable atoms have less energy.

Whether or not an atom's outermost shell is filled with electrons determines how stable the atom is. The atom is stable if the outer shell is filled. Because they are unstable, empty outer shell atoms typically form chemical bonds.

Learn more about neurons here:

https://brainly.com/question/24217914

#SPJ1

We were aware that SiO2 is a network covalent solid and that CO2 is a molecular solid, but I'm not sure how I would go about determining that.

Each silicon and carbon have the same number of valence electrons, and they both contain two oxygen atoms. Because solid sulfur dioxide is a molecule and has covalent bonds, it is not a network solid even if it is a solid and has covalent bonds. An example of a network solid is diamond. One of the many forms of elemental carbon found in nature, diamond is an allotrope of carbon. On an atomic level, it resembles this. The carbon atoms are linked together by the lines.

Learn more about molecular here-

https://brainly.com/question/4505951

#SPJ4

Acid-fast cell walls have a high content of lipids, including a waxy substance called mycolic acid.

The cell wall is composed of pectin when it is young, and when it matures it is formed from cellulose which is rigid. Cell walls are generally found in plants, but in the bacterium Myobacterium tuberculosis that causes tuberculosis, cell walls are also found.

Myobacterium tuberculosis has a wall composed of fat, polysaccharides and mycolic acid. Mycolic acid is a long-chain fatty acid linked to arabinogalactan by glycolipid bonds and peptidoglycan by phosphodiester bridges. The complex cell wall structure of these bacteria causes acid resistance.

Learn more about mycolic acid at:

https://brainly.com/question/5110275

#SPJ4

The layers of the earth include the following;troposphere, stratosphere, mesosphere, thermosphere, and exosphere. It's explanation will be discussed below.

The layers of the earth are grouped into five major layers that includes the following:

Troposphere: This is the layer of the earth that is closest to the earth's surface. It is characterized by having 78% nitrogen, 21% oxygen and remainder of trace gases (carbon dioxide, ozone, hydrocarbons, argon).

Stratosphere: This layers is located immediately above the troposphere. This layer is where ozone formation occurs and it's suitable for flying jets. It can be said that the stratosphere helps to protect us against ultraviolet rays of the sunlight.

Mesosphere: This is the layer found immediately above the stratosphere. This layer is characterized by having internal atmospheric gravity waves.

Thermosphere: This is the layer that is found immediately above the Mesosphere. It has the ability to absorb the sun's radiation.

Exosphere: This is the layer that is found immediately above the thermosphere. There is accumulation of the lightest gases such as hydrogen and helium in this layer.

Learn more about earth here:

https://brainly.com/question/25624188

#SPJ1

Answer:

Calcium Oxide must be Ionic, as we have one metal and one non metal involved. the metal is Calcium and the non metal is Oxygen. Meaning Calcium must be the one that transfers (loses) electrons to Oxygen, and Oxygen gains these electrons. It would look something like this:

Because Calcium transfers 2 electrons, it now has 2 more positively charged protons than the total number of electrons, as two electrons are lost. this means Calcium is no longer an atom, as it's positive protons and negative electrons can't cancel and make it neutral, it is now an ion, and a positively charged one at that. Same thing applies for Oxygen, but the opposite. because it has 2 more negative electrons than it's total of positive protons, it is now also an ion, and a negative one at that. The diagrams provided show the charges of the ions.

Potassium Nitrate must also be Ionic, for the same reason as before. the metal is Potassium and the non metal is Nitrogen. However, because Potassium is in Group 1, it only has 1 electron it can transfer to Nitrogen, but Nitrogen needs 2 electrons for a full outer energy level, therefore, we must have two Potassium atoms in this equation. It would look something like this:

Because there are two Potassium ions, each with a +1 charge, this means the overall charge of the Potassium ions is 2+, and this cancels out with the 2- provided by one ion of Nitrogen

NaCl is the limiting reactant in the given reaction.

You must figure out how many moles of each reactant are present to identify the limiting reactant. Utilizing each solution's concentration and volume can help you achieve this.

You have a volume of 94.0 ml and a concentration of 0.200 M for the AgNO3 solution. The AgNO3 solution has a volume of 0.094 liters after being converted from milliliters to liters by dividing by 1000 ml/L. The number of moles of AgNO3 may then be determined by dividing the concentration by the volume:

moles AgNO3 = concentration × volume

= 0.200 M × 0.094 L

= 0.0188 moles

You have a volume of 195.0 ml and a concentration of 0.201 M for the NaCl solution. The NaCl solution has a volume of 0.195 L after being multiplied by 1000 ml/L to convert the volume to liters. The number of moles of NaCl may then be determined by dividing the concentration by the volume:

moles NaCl = concentration × volume

= 0.201 M × 0.195 L

= 0.0401 moles

Learn more about the chemical reactions at

https://brainly.com/question/16862520?referrer=searchResults

#SPJ4

The number of electrons on a neutral atom is equal to the number of protons in the atom's nucleus, hence the answer is protons. This is referred to as the Z atomic number.

Atoms are neutral, hence there are exactly as many protons as electrons in each atom. All hydrogen atoms contain one electron, which is located outside the nucleus.

The number of protons and electrons in an atom's stable state is always equal to the atomic number. for a steady atom

Protons are positively charged and electrons are negatively charged. The number of electrons and protons in a neutral atom are always equal. The quantity of protons is constant.

To learn more about  neutral please click on below link

https://brainly.com/question/15395418

#SPJ4

The volume occupied at 25 °C. Remember to convert between °C and K. V2 = 3.311 L is the correct answer.

What is volume?

Volume is a measure of the amount of space occupied by an object, or the amount of matter contained within it. It is measured in units such as cubic metres, cubic centimetres, litres, millilitres, etc. Volume is a three-dimensional concept, meaning that it requires three measurements to be taken in order to accurately measure the amount of space an object occupies. The volume of a solid object can be determined by applying the formula V = l x w x h, where l is the length, w is the width, and h is the height of the object. For a liquid or gas, the volume is calculated by measuring its mass and the density of the substance. Volume can also be used to describe the total amount of space something occupies, such as the volume of a room or the volume of a storage container.

Temperature and Volume equation

Given,

The volume at -12°C = 2.90L

Temperature, T1 = -12°C

= (-12°C + 273)

= 261K

And, Volume at 25°C = ?

(25°C + 273)K

= 298K

Now, by using this equation:-

V1/T1 = V2/T2

V2 = V1 x T2/T1

V2 = 2.90L x 298K/261K

V2 = 3.311L

Hence, The volume at  25°C will be 3.311L

To learn more about Temperature and Volume equation

https://brainly.com/question/9956672

#SPJ1

A molecule of water contains hydrogen and oxygen in a 1:8 ratio by mass. this is a statement of the law of constant composition. Option B.

A water molecule is composed of hydrogen atoms and oxygen atoms bonded in a 2:1 ratio. Due to their fixed mass ratios, water molecules obey the law of constant proportions. Another example of a compound that obeys the law of constant ratios is methane.

To illustrate this, consider the production of water from molecular oxygen and hydrogen. Therefore mass is conserved. Conservation of mass can be used in chemical calculations. The law of conservation of mass states that matter cannot be created or destroyed.

Learn more about A molecule here:- https://brainly.com/question/26044300

#SPJ4

The concentration of sodium acetate (NaC₂H₃O₂) in the buffer solution is: 0.029 M.

A buffer solution is a solution that is resistant to changes in pH when small amounts of an acid or a base are added to it. It is able to do this because it contains both a weak acid and its conjugate base (or a weak base and its conjugate acid).

To determine the concentration of sodium acetate (NaC₂HO₂) in the buffer solution, you can use the Henderson-Hasselbalch equation:

pH = pKa + log([C₂H₃O₂-]/[HC₂H₃O₂])

where [C₂H₃O₂-] is the concentration of the acetate ion (the conjugate base of acetic acid) and [HC₂H₃O₂] is the concentration of acetic acid.

So, Plugging in the given values, we get:

4.31 = -log(1.8 x 10^-5) + log([C₂H₃O₂-]/1.0)

Solving for [C₂H₃O₂-] above, we see that it is = 0.029 M.

Since the concentration of sodium acetate is equal to the concentration of acetate ions, the concentration of sodium acetate in the buffer solution is also 0.029 M.

Learn more about buffer solution from

https://brainly.com/question/27371101
#SPJ1

See full question below

determine the concentration of sodium acetate (NaC₂H₃O₂)) in the buffer solution below.

a buffer solution with a ph of 4.31 is prepared with 1.0 m hc2h3o2 and --------m nac2h3o2. the ka of hc2h3o2 is 1.8 x 10^-5.