why is it important to thoughroughly mix each dilution before pipetting it into the next dilution and before plating it

Bronze is a homogeneous mixture of mostly copper with small amounts of another metal, such as tin. The solvent is coper and the solute is tin or small amounts of another metal. The solutions made from a metal and other solids called alloy.

Bronze is a uniform alloy made primarily of copper with trace amounts of other metals, like tin. Tin or trace amounts of one or more other metals are the solute and coper is the solvent. Alloys are mixtures created from metals and other substances.

Alloy, often known as a compound or a solution, is a metallic substance made up of two or more elements. Although carbon, a nonmetal, is a crucial component of steel, the components of alloys are typically metals themselves.

Learn more about alloy at https://brainly.com/question/29461159

#SPJ4

In an ecosystem, rain water harvesting is a  a solution of saving water as a resource .

Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.

Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .

Learn more about ecosystem,here:

https://brainly.com/question/13979184

#SPJ1

Answer:

NaOH + HCl → H2O and NaCl

Explanation:

hexanol or hexane: hexanol, propanol or butanol: butanol, dimethyl ether or ethanol: ethanol, pentanoic acid or pentanal: pentanoic acid

Enthalpy of vaporization is a measure of the amount of energy required to convert a substance from a liquid to a gas. In general, substances with higher molecular weights, polarities, and hydrogen bonding tend to have higher enthalpies of vaporization.

In the case of hexanol and hexane, hexanol has a higher molecular weight and is more polar due to the presence of a hydroxyl group. This results in a higher enthalpy of vaporization compared to hexane.

Similarly, butanol has a higher molecular weight compared to propanol and more hydrogen bonding due to the presence of a tertiary carbon atom, making it more polar. This results in a higher enthalpy of vaporization for butanol.

Ethanol has a higher molecular weight and is more polar compared to dimethyl ether. This leads to a higher enthalpy of vaporization for ethanol.

Pentanoic acid has a higher molecular weight and is more polar compared to pentanal, due to the presence of a carboxylic acid group. This results in a higher enthalpy of vaporization for pentanoic acid.

Learn more about hexane here:

https://brainly.com/question/14640336

#SPJ4

The flame test can be effectively used to identify a cation in a solution because when a cation is placed in a flame, it will emit a different color with

visibile light.

Ions are charged particles that form when atoms gain or lose electrons. When an atom gains electrons, it forms negatively charged ions called negative ions. On the other hand, positively charged ions, called cations, are formed when atoms lose electrons. These ions can be detected in solution using special tests. The flame test involves exposing a joint to a flame and identifying the joint by flame color. The color of the flame test is due to the fact that electrons in metal cations are excited and jump to higher energy levels.

For more information about flame test, visit :

https://brainly.com/question/11447098

#SPJ4

The most accurate lead test is the XRF Scan. X-ray Fluorescence (XRF) is an analytical technique used to determine the concentrations of elements in a sample.

What is lead test?

Lead test is a type of environmental analysis used to detect the presence of lead in water, soil, dust, and other materials. It is typically used to assess potential health risks associated with lead contamination and to monitor the effectiveness of any lead remediation efforts. Lead testing typically involves collecting samples of the material to be tested, which is then sent to a laboratory for analysis. The laboratory will then use a combination of chemical and physical tests to determine the lead content of the sample.

It works by bombarding a sample with X-rays, which causes the atoms in the sample to emit their own X-rays. These secondary X-rays can then be measured to determine the concentrations of elements in the sample. XRF is considered the most accurate and reliable method for detecting and measuring lead in a variety of materials.

To learn more about lead test
https://brainly.com/question/29801245

#SPJ4

According to unit conversion, 11.9 mg of sodium should be consumed by an average adult according to the data.

Unit conversion is defined as a multi-step process which involves multiplication or a division operation by a numerical factor.The process of unit conversion requires selection of appropriate number of significant figures and the rounding off procedure.

It involves a conversion factor which is an expression for expressing the relationship between the two units.A conversion ratio always has value which equals to one which indicates that numerator and denominator have values which are expressed in different units.

7% of 170 that is 7/100×170=11.9 mg.Thus, 11.9 mg of sodium should be consumed by an average adult according to the data.

Learn more about unit conversion,here:

https://brainly.com/question/19420601

#SPJ1

Answer:

3.82 g.

Explanation:

To calculate the mass of sulfuric acid produced from 1.25 g of sulfur, we'll have to balance the chemical equations and use stoichiometry.

Starting with the first reaction:

2S(s) + 3O2(g) → 2SO3(g)

Since 1.25 g of sulfur is reacted, the number of moles of sulfur can be calculated as:

moles = mass / molar mass = 1.25 g / 32 g/mol = 0.03906 mol

Next, using the mole ratio from the balanced chemical equation, we can find the number of moles of sulfur trioxide produced:

2 moles of sulfur produce 2 moles of sulfur trioxide, so:

moles of SO3 = moles of S x (moles of SO3 / moles of S) = 0.03906 mol x (2 mol / 2 mol) = 0.03906 mol

Finally, we move on to the second reaction, the dissolution of sulfur trioxide in water:

SO3(g) + H2O(l) → H2SO4(l)

Using the mole ratio from this balanced equation, we can find the number of moles of sulfuric acid produced:

1 mole of sulfur trioxide reacts with 1 mole of water to produce 1 mole of sulfuric acid, so:

moles of H2SO4 = moles of SO3 x (moles of H2SO4 / moles of SO3) = 0.03906 mol x (1 mol / 1 mol) = 0.03906 mol

The mass of sulfuric acid produced can be calculated using the moles and the molar mass of sulfuric acid:

mass = moles x molar mass = 0.03906 mol x 98 g/mol = 3.82 g

Therefore, if 1.25 g of sulfur is reacted, the mass of sulfuric acid produced is approximately 3.82 g.

The standard plate count (SPC) method is a widely used and simple method for enumerating bacteria in food and water samples. The advantage of using the SPC method over other enumeration methods is that it is a relatively low-cost and straightforward method.

that can provide a general estimate of the number of bacteria present in a sample. This method involves spreading a known volume of the sample onto a solid growth medium, incubating the plate, and counting the number of colonies that develop. The result is an estimate of the number of viable bacteria in the original sample. This method is useful for determining the general level of bacterial contamination in a sample and for monitoring changes in bacterial populations over time. However, it has some limitations, including the fact that not all bacteria will grow on the specific medium used and that some bacteria may be damaged or killed during the sample preparation and spreading process

You can read more about standard plate count  at https://brainly.com/question/29489516

#SPJ4

Answer:

Her speed is 6.8m/s.

Explanation:

K.E= 1/2mv²

or, 2543.2= 1/2×110×v²

or, 2543.2 = 55v²

or, 2543.2/55 = v²

or, 46.24 = v²

or, 6.8² = v²

v = 6.8 m/s

answer

6.8

explanation

k.e=1/2v^2

2543.2=55v^2

46.24=v^2

6.8^2=v^2

v=6.8

The formula of X is  Cu₂O and the formula of Y is CuO.

The masses of X and Y that can react with 0.5 g of oxygen are 4.0 g and 2.0 g of copper respectively.

The law that is illustrated by the result above​ is the law of multiple proportions.

The law of multiple proportions states that when two components combine to generate more than one compound, the combined weights of each element are in a ratio of tiny whole numbers.

The mole ratio of copper and oxygen in X and Y are:

X --> 1.365/64 : 0.17/16 = 0.02 : 0.01

mole ratio = 2 : 1

The formula of X is Cu₂O

Y ---> 1.16/64 : 0.29/16 = 0.02 : 0.02

mole ratio = 1 : 1

The formula of Y is CuO

The masses of X and Y that can react with 0.5 g of oxygen are calculated as follows:

Mass of copper to yield X = 0.5/16 * 2 * 64 = 4.0 g

Mass of copper to yield Y = 0.5/16 * 64 = 2.0 g

Learn more about the law of multiple proportions at: https://brainly.com/question/2624012

#SPJ1

Answer:

Explanation: When water temperatures rise, or fall, this can irritate, and stress the coral polyps, causing them to lose the algae that lives in the polyp's tissues.

Answer:

Coral reef species may be significantly impacted by a shift in water temperature. Coral bleaching is a condition when the coral expels their symbiotic algae, resulting in a loss of color and perhaps mortality. Sudden temperature fluctuations, especially rises, can induce coral bleaching. The prevalence of illnesses in corals and other reef species can also rise in response to an increase in water temperature. The distribution and behavior of fish and other species might change in response to temperature changes, possibly upsetting the delicate balance of the reef ecosystem. These effects may result in a reduction in the coral reef's biodiversity and general health.

To learn more about coral reefs visit: https://brainly.com/question/1287468

Answer:

Mass number

Explanation:

All atoms of the same element have the same number of protons, but some may have different numbers of neutrons, which would cause a different mass number

Answer:

The answer is mass number

D. by allowing the salt to evaporate .

Answer:

D.by allowing the salt to evaporate.

The mass of KOH needed to dissolve in 500 mL of water to produce a pH of 12.40 is 0.7 grams

We'll begin by obtaining the pOH of the solution. Details below:

pH + pOH = 14

12.40 + pOH = 14

Collect like terms

pOH = 14 - 12.40

pHO = 1.6

Next, we shall determine the hydroxide ion concentration [OH⁻] of the solution. Details below:

pOH = -Log [OH⁻]

1.6 = -Log [OH⁻]

Multiply through by -1

-1.6 = Log [OH⁻]

Take the anti-log of -1.6

[OH⁻] = Anti-log -1.6

[OH⁻] = 0.025 M

Next, we shall determine the molarity of KOH. details below:

KOH(aq) <=> K⁺(aq) + OH¯(aq)

From the balanced equation above,

1 mole of KOH contains 1 mole of OH¯

Therefore,

0.025 M Pb(CH₃COO)₂ will also contain 0.025 M OH¯

Next, we shall determine the mole of KOH in the solution. Details below:

Molarity = Mole / Volume

Cross multiply

Mole = molarity × volume

Mole of KOH = 0.025 × 0.5

Mole of KOH = 0.0125 mole

Finally, we shall determine the mass of KOH needed. Details below:

Mole = mass / molar mass

0.0125 = Mass of KOH / 56

Cross multiply

Mass of KOH = 0.0125 × 56

Mass of KOH = 0.7 grams

Therefore, the mass of KOH needed is 0.7 grams

Learn more about mass:

https://brainly.com/question/21940152

#SPJ1

There will be no reaction between aniline and NaH as both are base. The Arrhenius definitions of acid and base is restricted to compounds capable of producing H+ and OH ions.

The bronsted definitions of acid and base is restricted to compounds capable of producing H+ and OH ions within aqueous solutions. Although this is beneficial since water is indeed a liquid substance, it doesn't explain why some chemicals are acidic or basic.

In 1923, chemist Johannes Brnsted and English scientist Thomas Lowry introduced new definitions of acids and bases that focused on proton transport separately. Any species that may give a protons (H+) to some other molecule is referred to as a Brnsted-acid. There will be no reaction between aniline and NaH as both are base.

Therefore, there will be no reaction between aniline and NaH as both are base.

To learn more about Bronsted acid -base, here:

https://brainly.com/question/14407412

#SPJ1

The melting point have been unaffected if the sample had not completely dissolved.

What is melting point?

Melting point is the temperature at which a solid transforms into a liquid. It is the temperature at which the particles in a solid can no longer maintain their rigid structure, and the solid becomes a liquid. Each substance has its own unique melting point, and it is determined by the strength of the forces between the particles in the solid. Melting points can range from just above 0°C for water, to over 3000°C for some metals. The melting point also affects the boiling point of a substance, as the boiling point is the temperature at which the liquid will transform into a gas. Knowing the melting point of a substance can be helpful in determining the properties of a material and the amount of energy needed for melting or boiling.

To learn more about melting point
https://brainly.com/question/40140

#SPJ4

The molecular formula is C4H8 of a hydrocarbon has a molar mass between 50 and 60 g/mol.

Mass of CO2 = 3.14 grams

Mass of H2O = 1.28 grams

Molar mass = 50 g/mol

Molar mass C = 12.01 g/mol

Molar mass H = 1.01 g/mol

Molar mass O = 16.0 g/mol

Step 2: Calculate moles CO2

Moles = mass / molar mass

Moles CO2 = 9.603 grams / 44.01 g/mol

Moles CO2 = 0.218 moles

Step 3: Calculate moles C

For 1 mol CO2 we have 1 mol C

For 0.218 moles CO2 we have 0.218 moles C

Step 4: Calculate mass C

Mass C = 0.218 moles * 12.01 g/mol

Mass C = 2.618 grams

Step 5: Calculate moles H2O

Moles H2O = 1.573 grams / 18.02 g/mol

Moles H2O = 0.0873 moles

Step 6: Calculate moles H

For 1 mol H2O we have 2 moles H

For 0.0873 moles H2O we have 2* 0.0873 = 0.1746 moles

Step 7: Calculate mass H

Mass H = 0.1746 moles * 1.01 g/mol

Mass H = 0.176 grams

Step 8: Calculate mol ratio

We divide by the smallest amount of moles

C: 0.218 moles / 0.1746 moles = 1.25

H: 0.1746 moles / 0.1746 moles =  1

The molecular formula is C4H8.

Learn more about molar mass:

brainly.com/question/14425592

#SPJ4

When a red blood cell is placed into each of the following solutions, then crenation will occur in solution A,D,E ; hemolysis will occur in B,C solutions.

When red blood cells (erythrocytes) are placed in a hypertonic solution, they contract. This is because the hypertonic fluid has a lower water potential than the cell content. In this case, osmotic pressure occurs, resulting in an abnormal notch along the edge of the red blood cell. This phenomenon is called creation. The process of destruction of red blood cells, including premature destruction of red blood cells, is called hemolysis. There are 5 different solutions and a red blood cell is placed in each solution. We have to determine the solutions in which hemolysis or creation process will occur. So, A, D , and E ( 3.21 % Nacl , 6.97 % glucose, 5.0 % mg glucose and 0.9 % Nacl ) these all solution act as hypertonic solution when RBC are placed. So water molecules moves in to the solution and cause crenation of RBC.

Hemolysis :- Distill water and 1.67 % glucose are act as hypotonic solution around the RBC cells . So water flows inside if the RBC cause its swelling and bursting or hemolysis.

For more information about homolysis, visit:

https://brainly.com/question/29031620

#SPJ4

The mass percent of K₂SO₄ in a mixture of BaSO₄ and SO₄ is 74.56%

The molecular weight of K₂SO₄ is 174.26 g/mol

The molecular weight of BaSO₄ is 233.38 g/mol

The molecular weight of SO₄ is 96 g/mol

let the mass fraction of  K₂SO₄ is x and mass fraction of BaSO₄ is y so:

x+y = 1

Then from the given data

total mass of the mixture = x*174.26 + y*233.38 -----------(1)

total mass of the mixture = (x+y)*mass of SO4/ percentage of SO4

                                          = (x+y)96/0.5071 ----------(2)

by equating 1,2

x*174.26 + y*233.38 = (x+y)96/0.5071

x*174.26 + y*233.38 = (x+y)189.3

      y(233.38-189.3) = x(189.3-174.26)

                  y(44.08) = x(15.04)

                              y = 0.341x

and we know.

x + y = 1

then

x + 0.341x = 1

              x = 1/1.341

              x = 0.7456

The mass percent of K₂SO₄ is 74.56%

Learn more about mixture mass at https://brainly.com/question/30400742

#SPJ4

The first step in the hydrogenation of double bonds is often referred to as "adsorption" or "adsorption of reactants."

During this step, the reactants i.e., the unsaturated molecule and hydrogen gas are brought into close proximity with the metal surface of the catalyst, allowing for their interaction.

In the adsorption step, the unsaturated molecule is adsorbed onto the metal surface of the catalyst, while the hydrogen gas molecules are also adsorbed, often in a dissociated form as hydrogen atoms. The close proximity of the reactants on the metal surface enables their reaction to occur more efficiently, due to the increased likelihood of collisions between reactant species.

It's worth noting that the adsorption step is followed by the actual hydrogenation reaction, in which the double bond is reduced and hydrogen atoms are added, thus forming a saturated molecule. The metal surface of the catalyst plays a critical role in promoting this reaction by providing the necessary activation energy and by facilitating the transfer of electrons between reactants.

To learn more about  Hydrogenation :

https://brainly.com/question/28213898

#SPJ4

The mechanism of glyceraldehyde 3-phosphate dehydrogenase in glycolysis  does not include phosphorylation of the substrate using ATP. Hence, option a is false.

Glyceraldehyde 3-phosphate dehydrogenase, or GAPDH, is an enzyme with a molecular mass of approximately  37 kDa that catalyzes glycolysis' sixth stage, converting glucose into energy and carbon molecules.

Initially, the carbonyl group of GAP is attacked by a cysteine residue in the active site of GAPDH, resulting in the formation of a hemithioacetal intermediate (covalent intermediate).

At the active site of the enzyme, a histidine residue deprotonates the hemithioacetal . In the ensuing thioester intermediate, deprotonation promotes the reformation of the carbonyl group and the ejection of a hydride ion. Not any step include the use of ATP. Thus, option a is false.

Find more on glycolysis:

https://brainly.com/question/15159050

#SPJ1

Your question is incomplete. But, your complete question probably was:

The mechanism of glyceraldehyde-3-phosphate dehydrogenase does NOT involve. true or false?

A phosphorylation of the substrate using ATP.

B oxidation and phosphorylation of the substrate.

C a covalent intermediate.

D an active site histidine to serve as a proton acceptor.

O2 is both a reactant and a product in chemical reactions. During a reaction, oxygen molecules (O2) are consumed as a reactant

O2 is both a reactant and a product in chemical reactions. new oxygen molecules are formed as a product. This is how oxygen is recycled in nature.Oxygen is also found in microorganisms, where it is used for respiration and energy production. Plants are also able to use oxygen for respiration and for the production of energy. Plants also store oxygen in their cell walls and in their tissue, allowing them to absorb more oxygen from their environment. Additionally, oxygen is part of the structure of some plant cells, as a component of their cell walls and membranes.

Learn more about oxygen here:

https://brainly.com/question/1506082

#SPJ4

When all the atoms in a molecule have the same atomic number, the substance is an element. If their atomic numbers differ, it is a compound.

Elements are pure substances that contain only one type of atom. Compounds are substances formed by the chemical union of two or more different types of elements in fixed proportions. There are currently nearly 118 elements, of which nearly 94 occur naturally on Earth.

An element is a substance that cannot be broken down into chemically simpler components. Aluminum is a chemical element that is found in soda cans. A compound is a substance that can be broken down into chemically simpler components.

Thus,the chemist conclude whether the substance is an element or a compound

To learn more about the elements and compound, follow the link;

https://brainly.com/question/13516179

#SPJ1

A chemist can conclude whether the sample is an element or compound by some qualitative tests. If it is  compound it gives positive results for multiple elements.

Compounds are formed by the combination of atoms of different elements. It can be pure substance or mixture. There are different kinds of compounds such as ionic compound, covalent compound , coordination compounds etc.

Elements are pure substance which cannot be split to its constituents. Hence, we can test by some qualitative techniques to identify whether the substance is a mixture or pure substance.

If the tests are giving positive results for multiple elements it is a compound. If it is a mixture it can be separated using techniques such as distillation, chromatography etc.

Find more on compounds:

https://brainly.com/question/14658388

#SPJ1

There would be 660.48 gr 3. 01 x 10^24 molecules of (NH₄)₂SO₄

The quantity of the substance must then be divided into atoms, or moles. Avogadro's constant (6.02214179x 10²³) / one mole of substance is required as the conversion factor when going from moles of a substance to atoms.

To calculate the mass first we sholudd calculate the moles of (NH₄)₂SO₄.

​Number of Moles = given number of molecules

                                         NA

Number of Moles =  3. 01 x 10²⁴

                               6.02 x 10²³

Number of moles = 4.998 moles

The we can calculate the mass by multiplying moles with mass molar

Mass  (NH₄)₂SO₄ = moles x mass molar

Mass  (NH₄)₂SO₄ =  4.998 moles x  132.14 g/mol

Mass  (NH₄)₂SO₄ = 660.48 grams

​

Learn more about molecules at https://brainly.com/question/30368346

#SPJ4

Monosaturated fatty acid contains

B. One double bond

Monounsaturated fatty acids contain one double bond.

Monounsaturated fatty acids are fatty acids that contain one double bond in their carbon chain. This results in a kink in the shape of the fatty acid molecule, which affects its physical and chemical properties. Monounsaturated fatty acids are considered a healthier alternative to saturated fatty acids, which contain no double bonds and can raise cholesterol levels. Monounsaturated fatty acids are found in foods such as olive oil, avocado, and nuts.

Learn more about fatty acids here:

https://brainly.com/question/5710423

#SPJ4

Polar water molecules have partial positive and negative charges on their both the ends. Because of their diametrically opposed charges, water molecules are drawn to one another by ionic bonds.

The main interaction taking place in ionic compounds is ionic bonding, a form of chemical bonding that includes the electrostatic attraction between two atoms or ions with dramatically differing electronegativities.

An atom may establish bonds with other atoms in two main ways. They are covalent and ionic. The sharing of electrons between two or more atoms, they in turn properly form a covalent connection. When two or more ions join in contact, they can create ionic bonds that are kept together by charge differences.

A water molecule contains two poles.  It is a positive charge on the hydrogen pole along with a negative charge on the oxygen pole. This is due to the uneven sharing of electrons between the atoms and the asymmetrical form of the molecule.

Thus, water molecules are drawn to one another by ionic bonds.

To learn more about ionic bond:

brainly.com/question/977324

#SPJ4

The balanced chemical equation for the combustion of liquid hexane in oxygen gas is: C6H14(l) + 19O2(g) -> 6CO2(g) + 14H2O(g)

In this equation, hexane (C6H14) is a liquid reactant and oxygen gas (O2) is a gaseous reactant. The products, carbon dioxide (CO2) and water vapor (H2O), are both in the gaseous state. To balance the equation, the coefficient 19 was used for the oxygen gas to ensure that the number of oxygen atoms in the reactants and products is equal. Similarly, the coefficients 6 and 14 were used for the carbon dioxide and water vapor, respectively, to balance the number of carbon and hydrogen atoms in the equation.

Learn more about oxygen here:

https://brainly.com/question/13370320

#SPJ4