Convert a pressure of 250 torr to atm a) 0.266 atm b) 0.279 atm c) 0.329 atm d) 0.297 atm

the mass of boron present in 30 g of borax is ​1.991×10²⁴

Chemical element boron has the atomic number 5 and the letter B in its symbol. It is an amorphous brown powder and a brittle, black, glossy metalloid in its crystalline form. There may be antioxidant effects of boron. Boron is frequently used to treat vaginal yeast infections and boron insufficiency. Additionally, it is used to treat menstrual cramps, osteoarthritis, osteoporosis, and numerous other ailments, but many of these applications lack strong scientific backing.

Molar mass of B = 10.81g/mol

So, 1 mole of B = 10.81g

and 1 mole = NA= 6.023×10²³

By combining,

10.81g of B = 6.023×10²³ atoms of B thus,

35.76g of B = 6.023×10²³

10.81×35.76

35.76g of B

= 1.991*10²⁴

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Answer:

6.3

Explanation:

multiply the length value by 100

Answer:A

Explanation:

Species evolve at different rates. for example, bacteria are unlikely to become extinct because they adapt more quickly than mammals to environmental changes. Bacteria reproduce more rapidly, allowing species to evolve more quickly best explains this difference. Therefore, option A is correct.

Bacterial species evolve quickly because of their large populations, which provide numerous opportunities for mutations, and because they readily exchange genetic information, even between species. Some of this genetic diversity influences drug sensitivity or resistance, providing material for Darwinian selection.

Bacteria are among the world's fastest reproducing organisms, doubling every 4 to 20 minutes. Some pathogenic strains of E. coli grow quickly.

Bacterial populations evolve antibiotic resistance so quickly due to their fast generation times, large population sizes, and unique gene acquisition methods. These are some of the reasons bacteria have been so successful in evolution.

Thus, option A is correct.

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Answer:

+ Triple covalent bond (CB) > double CB > single CB in terms of bond strength and energy needed to break the bonds

+ Triple bonds are the most reactive, double bonds are reactive but single bonds are unreactive

+ Single bond > double bond > triple bond in bond length

+ in single bond, 2 electrons are shared
+ in double bond, 4 electrons are shared
+ in triple bond, 6 electrons are shared

Therefore, at 1.82 atm and 22°C, 218 mol of H2 will fill a volume of 888 L.

1 mole of any gas will take up 22.4 L of space at Standard Temperature and Pressure (STP). The quantity may be determined using the Ideal Gas Law and a balanced chemical equation.

The ideal gas law can be used to resolve this issue:

PV = nRT

The temperature must first be converted to Kelvin by adding 273.15:

T =22°C+273.15

= 295.15 K

After that, we may enter the following values:

P = 1.82 atm

n = 218 mol

R = 0.0821 L·atm/mol·K (gas constant)

So the equation becomes:

V = nRT / P

V = (218 mol)(0.0821 L·atm/mol·K)(295.15 K) / (1.82 atm)

V = 888 L.

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Answer:

i like butting hole

Explanation:

mkrkr

Answer:

C→O, O→Cl, O→F, C→N, C←Li, S ←H, S→Cl

Explanation:

The general convention for indicating polarity in molecules is that of showing the direction of polarity from the positive to the negative part of the bond. This is indicated in the answer by arrows that show the direction of the dipole.

The negative end of the dipole must be the more electronegative element while the positive end of the dipole is the less electronegative element, hence the answer shown above.

The delta notation, indicating the polarity of for the presented covalent bonds are:

Polar bonds are those in which atoms have different electronegativities.

The delta notation is used to indicate the direction of the polarity.

The atom with the greater electronegativity acquires a partial negative charge (goes with the symbol δ-), while the atom with the lesser electronegativity acquires a partial positive charge (goes with the symbol δ+).

Let's consider the following elements with their electronegativities.

The delta notation for the presented bonds are:

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The molarity of Zn in the solution is 26.83.

Define molarity.

The amount of a substance in a specific volume of solution is known as its molarity (M). The number of moles of a solute per liter of a solution is known as molarity.

Density = 8760 kg/m^3  = 8760 kg/1000 liters  = 8.76 kg/liter = 8.76 gm/ml

Out of 100 gm 80 gm is copper and 20 gm is zinc

Now  considering 100 gm solution,  zinc  moles = mass / atomic mass = 20 / 65.38  = 0.3059

Zinc is solute and copper is solvent

Now, molality = moles of solute  / solvent mass in kg  

= 0.3059 / ( 0.08)  

= 3.82

Solution vol = solution mass/density

= 100/8.76

= 11.4 ml

= 0.0114 L

Now,

Molarity = moles of solute / solution vol in liters  

= 0.3059/0.0114

= 26.83

Therefore, the molarity of Zn in the solution is 26.83.

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Complete question:

Brass is a substitutional alloy consisting of a solution of copper and zinc. A particular sample of red brass consisting of 80.0% Cu and 20.0% Znby mass has a density of 8760kg/m3 .

What is the molality of Zn in the solid solution? express your answer in the unit of mol/kg

What is the molarity of Zn in the solution?

The noble gases are the most stable elements in nature. They rarely react with other elements since they are already stable. Why? Because they have 8 electrons in their outer shell (except from Helium that has 2), They have the maximum amount of valence electrons that their outer shell can hold.

(a) the molecular formula of the compound is C₆H₁₂.

(b)  the molecular formula of the compound is NH₂Cl.

(a) Given the empirical formula CH₂ and a molar mass of 84 g/mol, we need to determine the molecular formula. To do so, we need to find the factor by which the empirical formula needs to be multiplied to achieve the given molar mass.

The empirical formula CH₂ has a molar mass of 14 g/mol (12 g/mol for carbon + 2 g/mol for hydrogen).

To find the factor, we divide the molar mass by the empirical formula mass:

Factor = (molar mass) / (empirical formula mass) = 84 g/mol / 14 g/mol = 6

Therefore, the molecular formula is obtained by multiplying the empirical formula by the factor:

CH₂ × 6 = C₆H₁₂

Thus, the molecular formula of the compound is C₆H₁₂.

(b) Given the empirical formula NH₂Cl and a molar mass of 51.5 g/mol, we follow a similar approach.

The empirical formula NH₂Cl has a molar mass of 51.5 g/mol (14 g/mol for nitrogen + 2 g/mol for each hydrogen + 35.5 g/mol for chlorine).

To find the factor, we divide the molar mass by the empirical formula mass:

Factor = (molar mass) / (empirical formula mass) = 51.5 g/mol / 51.5 g/mol = 1

Therefore, the molecular formula is the same as the empirical formula: NH₂Cl

Hence, the molecular formula of the compound is NH₂Cl.

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Magnesium reacts quickly with HCl while iron reacts more slowly with HCl. Copper does not react at all with HCl.

We have to  recall that the reactivity of metals is determined by the position of the metal in the electrochemical series. This is an  arrangement of metals from more reactive to least reactive.

Magnesium and iron  reactwith dilute HCl to give hydrogen gas but the rates of reaction differ. Magnesium reacts fastest with HCl followed by iron but copper does not react with HCl at all.

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The combustion of lauric acid is shown as CH3(CH2)10COOH(s) + 18O2(g) -----> 12H20(l) + 12CO2(g)

In a combustion reaction, a substance is burnt in oxygen. If the substance is an organic compound a the case is here, the products are carbon dioxide and hydrogen.

No the equation of the combustion of lauric acid is shown as;

CH3(CH2)10COOH(s) + 18O2(g) -----> 12H20(l) + 12CO2(g)

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In the 1920s, western powers began to expand their influence in the middle east primarily due to A. The discovery of oil in the region.

In the 1920s, the Western powers, such as Britain and France, began to expand their influence in the Middle East primarily due to the discovery of oil in the region. The discovery of oil brought enormous economic and strategic importance to the region, and the Western powers sought to secure their access to this valuable resource. The discovery of oil also helped to modernize the region, as the Western powers invested in infrastructure development, such as pipelines, ports, and railways, which facilitated the transportation of oil and other goods. The Western powers also sought to protect their interests in the region by establishing protectorates, such as Kuwait and Bahrain, and by dividing up the former Ottoman Empire into new nation-states that would be more amenable to Western influence. This led to a backlash from some in the region, who saw the Western powers as meddling in their affairs, and who called for greater independence and self-determination. Nonetheless, the discovery of oil in the region had a profound impact on the political and economic development of the Middle East and continues to shape the region's geopolitics today.

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Based on the data shown in the graph, the rate of reaction is directly proportional to the temperature of a reaction.

The speed at which a chemical reaction occurs is called the reaction rate or rate of reaction. The rate of a reaction is proportional to the increase in product concentration per unit time and the decrease in reactant concentration per unit time.

The rate of a reaction is affected by the following:

the temperature of the reaction - the rate of reaction is directly proportional to the temperature of a reaction. Hence, the rate of a reaction increases with an increase in temperature.

presence of a catalyst - the rate of a reaction increases with the addition of a catalyst. A catalyst speeds up the rate of a reaction.

the surface area of the reactants - the rate of a reaction increases with an increase in the surface area of the reactants,

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Answer:

At higher temperatures, chemical reactions occur more quickly.

Explanation:

edmentum

Dipolar molecules have a separation of charge with a positive center and a negative center located at two different points, resulting in a net dipole moment. The correct option is true

Dipolar molecules are molecules that have a separation of charge, resulting in a positive center and a negative center located at two different points in the molecule.

This separation of charge creates a net dipole moment, which is a measure of the molecule's polarity. The magnitude and direction of the dipole moment depend on the difference in electronegativity between the atoms in the molecule and the molecule's geometry.

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Answer:

We can use the information given in the problem to calculate the RAM (relative atomic mass) of X and the minimum volume of hydrogen used in the reaction.

First, we need to calculate the mass of oxygen in the oxide XO:

mass of oxygen = mass of oxide - mass of metal

mass of oxygen = 4.5 g - 3.6 g

mass of oxygen = 0.9 g

Next, we can use the mass of oxygen to calculate the number of moles of oxygen:

moles of oxygen = mass of oxygen / molar mass of oxygen

moles of oxygen = 0.9 g / 16.00 g/mol

moles of oxygen = 0.05625 mol

Since the oxide XO is formed by the combination of X and oxygen, we can assume that the mass of X in the oxide is equal to the mass of the oxide minus the mass of oxygen:

mass of X = mass of oxide - mass of oxygen

mass of X = 4.5 g - 0.9 g

mass of X = 3.6 g

We can use the mass of X and the number of moles of oxygen to calculate the number of moles of X:

moles of X = mass of X / atomic mass of X

moles of X = 3.6 g / atomic mass of X

Combining this with the stoichiometry of the reaction, which tells us that 1 mole of XO reacts with 1 mole of H2 to produce 1 mole of X and 1 mole of H2O, we can write:

moles of H2 = moles of X / 1 = (3.6 g / atomic mass of X) / 1

To determine the minimum volume of hydrogen at STP (Standard Temperature and Pressure), we can use the ideal gas law:

PV = nRT

where P is the pressure, V is the volume, n is the number of moles, R is the universal gas constant, and T is the temperature. At STP, the pressure and temperature are 1 atm and 273 K, respectively, and the universal gas constant is 0.08206 L atm/(mol K).

Substituting the given values and solving for V, we get:

V = nRT/P = [(3.6 g / atomic mass of X) / 1] * (0.08206 L atm/(mol K)) * 273 K / 1 atm

Simplifying and solving for the atomic mass of X, we get:

atomic mass of X = (3.6 g / V) * (1 mol/2 mol of H2) * (1 mol of XO/1 mol of X) * (16.00 g/mol of oxygen + atomic mass of X)

Substituting the given values, we get:

atomic mass of X = (3.6 g / V) * (0.5) * (1 / 1) * (16.00 g/mol + atomic mass of X)

Multiplying out, we get:

atomic mass of X = (1.8 g / V) * (16.00 g/mol + atomic mass of X)

Solving for atomic mass of X, we get:

atomic mass of X = (1.8 g / V) * 16.00 g/mol / (1 - 1.8 g / V)

Substituting V = 22.4 L (the volume of 1 mole of gas at STP), we get:

atomic mass of X = (1.8 g / 22.4 L) * 16.00 g/mol / (1 - 1.8 g / 22.4 L)

atomic mass of X ≈ 56.1 g/mol

Therefore, the RAM of X is approximately 56.1 g/mol, and the minimum volume of hydrogen used in the reaction is approximately 22.4 L at STP.

The specific heat capacity of a substance, also known as the massic heat capacity or massic heat capacity in thermodynamics, is the heat capacity of a sample of the substance divided by the mass of the sample. So, the energy gain by sample will be 506J

We know that, the heat energy gained will be calculated by the formula,

Q=mcΔT

where,

Q= Heat energy gained

m=mass

c= specific heat capacity

ΔT= Change in temperature

So, Given,

m= 5.00g ,

ΔT= 419K -306K= 113K

c= 0,897J/gK

Q=mcΔT

Q= 5.0×0.897×113

Q= 506J

So, the energy gained by sample of Aluminum will be 506 J when it is warmed from 306 K to 319K , in which temperature difference is 113K

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Ideal gas law is valid only for ideal gas not for vanderwaal gas. To solve such, we need to know the relation between rate of effusion and molar mass of gases. Therefore, the new volume V₂ is 18L.

Ideal gas equation is the mathematical expression that relates pressure volume and temperature. an ideal gas on the walls of the container is inversely proportional to the volume occupied that gas.

Mathematically, Boyle's law can be written as

P₁V₁ = P₂V₂

P₁=initial pressure=342 torr

P₂=final pressure=1710 torr

V₁ = initial volume= 29.0 L

V₂=final pressure=?

Substituting all the given values in the above equation, we get

V₂ = P₁V₁/P₂

V₂ = (342 × 29.0)/1710

V₂ = 18L

Therefore, the new volume V₂ is  18L.

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An iron rod used in construction sites does not shine because it is often coated with a layer of rust.

What is rust ?

Rust is a type of corrosion that occurs when iron or steel is exposed to oxygen and moisture over time.

Metals are lustrous because of their ability to reflect light due to the presence of free electrons in their outermost energy levels. When light strikes a metal surface, these free electrons absorb the energy of the light and then re-emit it in all directions, giving the metal its characteristic shine. However, an iron rod used in construction sites does not shine because it is often coated with a layer of rust or other contaminants that can prevent the reflection of light. Rust is formed by the reaction of iron with oxygen in the presence of water or moisture. This rust layer can obscure the metallic luster of the iron and make it appear dull. Additionally, the iron used in construction sites is often not polished or finished to a high degree, which can also contribute to its lack of shine. The surface of the iron can have rough edges or irregularities that can scatter light, rather than reflect it uniformly, leading to a loss of shine.

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Answer:

The more easily these cations form, the more reactive the metal.

Explanation:

Answer:

this is of effective nuclear charge.

In this question, we have the following reaction:

CuSO4 + Zn -> Cu + ZnSO4, as the question already says, this is a single replacement reaction

We have:

145.0 grams of Cu (Copper)

We have to find out how much Zn we had at the beginning of the reaction

First thing we need to do is find out how many moles of Copper we have, we will do it by using its molar mass, 63.55g/mol, and the given mass in the question, 145g

63.55g = 1 mol

145g = x moles

x = 2.28 moles of Copper in 145 grams

Now, according to the molar ratio, if we have 1 mol of Zn, we will produce 1 mol of Cu, therefore if we have 2.28 moles of Cu, we will have 2.28 moles of Zinc as well

Now we will find the mass of Zinc, using the number of moles, 2.28 moles and its molar mass, 65.38g/mol

65.38g = 1 mol

x grams = 2.28 moles

x = 149.1 grams of Zinc was used

Answer: Number of atoms of Fe = 5.214x10²²atoms

Explanation:

First, we'll calculate the number of moles of Fe using the given number of atoms:

Number of moles = Number of atoms / Avogadro's number-----------(i)

Number of atoms of Fe = 5.22x10²²atoms    

Avogadro's number = 6.022x10²³atoms/mol)

now putting values in equation (i)

Number of moles = 5.22x10²²atoms  ₓ 6.022x10²³atoms/mol)    

Number of moles of Fe = 0.0866 moles

To find the number of atoms of Fe, we can use Avogadro's number again:

Number of moles = Number of atoms / Avogadro's number-----------(i)

Number of moles of Fe = 0.0866 moles

Avogadro's number = (6.022x10²³atoms/mol)

Number of atoms of Fe = 5.214x10²²atoms

The average reaction rate for oxygen gas is 49.26 mL/s

The average reaction rate of a substance refers to the speed at which a reaction occurs and therefore products are formed. In the reaction presented, oxygen gas is the product.

Moreover, the average reaction rate can be expressed in mL per second or mL/s, and the formula to calculate it is:

Product in mL/seconds

Let's calculate the reaction rate:

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The stage that this most accurately describes while using the PCR is the initiation of DNA synthesis, also known as the denaturation stage.

In the denaturation stage of Polymerase Chain Reaction (PCR), the double-stranded DNA template is heated to a high temperature to separate the two complementary strands and create single-stranded DNA. The denaturation stage is the first step in the PCR cycle.

In this stage, the heat-stable DNA polymerase denatures the DNA and the primers anneal to the complementary single-stranded template. This marks the beginning of the extension stage, where the DNA polymerase synthesizes new complementary strands along the template DNA.

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The name of the salt tells us that:

a) there is just one other element combined with the metal by looking at the suffix of the salt's name.

b) the presence of oxygen in a salt can be indicated by the name of the salt.

a) The name of a salt can tell us that there is just one other element combined with the metal by looking at the suffix of the salt's name. If the salt name ends in "-ide," it indicates that the salt is composed of a metal and a single non-metal element.
For example, sodium chloride (NaCl) and potassium bromide (KBr) are salts where the metal (sodium and potassium) is combined with a single non-metal element (chlorine and bromine, respectively). The "-ide" suffix suggests the presence of only one other element in the salt.

b) The presence of oxygen in a salt can be indicated by the name of the salt. If the salt name includes the element oxygen, it suggests that oxygen is present in the salt compound.
For example, sodium carbonate (Na₂CO₃) and calcium sulfate (CaSO₄) contain the element oxygen in their chemical formulas. The presence of oxygen in the salt is implied by the name and the combination of elements in the compound.

Therefore, the name of salt tells us that there is just one other element combined with the metal and there is oxygen present in the salt

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Answer:

Filter it

Explanation:

The amount of heat energy produced when 1 g of hydrogen and 2 g of nitrogen are reacted, is -6.61 KJ

First, we shall obtain the limiting reactant. Details below:

3H₂ + N₂ -> 2NH₃

From the balanced equation above,

28 g of N₂ reacted with 6 g of H₂

Therefore,

2 g of N₂ will react with = (2 × 6) / 28 = 0.43 g of H₂

We can see that only 0.43 g of H₂ is needed in the reaction.

Thus, the limiting reactant is N₂

Finally, we the amount of heat energy produced. Details below:

3H₂ + N₂ -> 2NH₃ ΔH = -92.6 KJ

From the balanced equation above,

When 28 grams of N₂ reacted, -92.6 KJ of heat energy were produced.

Therefore,

When 2 grams of N₂ will react to produce = (2 × -92.6) / 28 = -6.61 KJ

Thus the heat energy produced from the reaction is -6.61 KJ

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Answer:

The volume of Component 1 is 36 cubic inches.

Explanation:

To calculate the volume of a composite solid, we need to determine the individual volumes of the different components and then add them together.

In this case, the composite solid consists of multiple components with the following dimensions:

Component 1:

Length: 4 inches

Width: 3 inches

Height: 3 inches

To find the volume of Component 1, we multiply the length, width, and height together:

Volume of Component 1 = Length x Width x Height = 4 in x 3 in x 3 in = 36 cubic inches

Therefore, the volume of Component 1 is 36 cubic inches.

Please provide the dimensions of the remaining components of the composite solid, and I will calculate the total volume by summing up the individual volumes.

Answer:   a.b.d

Explanation:

Answer:

A)There is no rainbow-like halo around the image. Yes

B)Reflecting telescopes can be made very large. Yes

C)Reflecting telescopes use only lenses, not mirrors. No

D)Only the reflecting side of the primary mirror needs to be perfectly shaped and smooth. Yes

E)The eyepiece creates an image for the observer. No

Answer:

1413.386

Explanation: