True or False: Most metals are found to occur naturally in their uncombined states.

Answer:

mass

Explanation:

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Answer:

87.50g(1cm^3/1.1738g)=50.345 cm^3

Explanation:

volume units id in cubic centimeters

The dilution factor : 100

The dilution factor(DF) : ratio of concentration of stock solution and diluted solution or ratio of the volume of final solution to the initial volume from stock solution

From equation of dilution :

M₁V₁=M₂V₂

[tex]\tt DF=\dfrac{M_1}{M_2}=\dfrac{V_2}{V_1}[/tex]

Volume of aliquot = 0.1 ml

Volume of diluent = 9.9 ml

So final volume :

[tex]\tt V_f(final~volume)=volume~aliquot+volume~diluent\\\\V_f=0.1+9.9=10~ml[/tex]

The dilution factor (DF) :

[tex]\tt D_f=\dfrac{V_f}{V_i}\\\\D_f=\dfrac{10}{0.1}=100[/tex]

Geologic Tools. Geologists use a lot of tools to aid their studies. Some of the most common tools used are compasses, rock hammers, hand lenses, and field books.

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Answer:

it is probably acrylic or latex

Explanation:

There are two types of chemical compound one is covalent compound and other is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Therefore, the type of paint is  acrylic or latex.

Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.

An ionic compound is a metal and nonmetal combined compound.  Ionic compound are very hard. They have high melting and boiling point because of strong ion bond.  If the chip remains flat when put in ethanol, it is probably an oil-based paint. If the chip curls, it is probably acrylic or latex. So, The type of paint is  acrylic or latex.

Therefore, the type of paint is  acrylic or latex.

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Answer: (a) [tex]\Delta S^{0}[/tex] = - 242.2J/K.mol

              (b) [tex]\Delta S^{0}[/tex] = 163.34J/K.mol

              (c) Yes

Explanation: Entropy is the measure of randomness or disorder of a system. Standard Entropy has the symbol [tex]S^{0}[/tex].

Mathematically, Entropy is defined as

[tex]\Delta S^{0}=\Sigma S^{0}(products)-\Sigma S^{0}(reagents)[/tex]

Each substance has its own entropy value.

(a) Combustion of Methane:

[tex]CH_{4}+2O_{2}[/tex] ⇒ [tex]CO_{2}+2H_{2}O[/tex]

Using standard entropy table, entropy will be:

[tex]\Sigma S^{0}(products)=214+2(69.91)[/tex] = 353.8

[tex]\Sigma S^{0}=186.264+2(205.138)[/tex] = 596.54

[tex]\Delta S^{0}=[/tex] 353.8 - 596.54

[tex]\Delta S^{0}=[/tex] - 242.2

Standard Entropy for combustion of methane is [tex]\Delta S^{0}=[/tex] - 242.2 J/K.mol.

(b) Hydrolysis of Water:

[tex]H_{2}O_{(l)}[/tex] ⇒ [tex]H_{2}_{(g)}+1/2O_{2}_{(g)}[/tex]

[tex]\Sigma S^{0}(products)=130.684+0.5(205.138)[/tex] = 233.253

[tex]\Sigma S^{0}(reagents)=69.91[/tex]

[tex]\Delta S^{0}=[/tex] 233.253 - 69.91

[tex]\Delta S^{0}=[/tex] +163.34

Standard Entropy for hydrolysis of water is [tex]\Delta S^{0}=[/tex] + 163.34 J/K.mol

(c) Yes, the results prove the general rule: Reactions Entropies are positive for net formation of gas and negative for net reduction of gas. This happens because, as entropy is the measure of disorder, the entropy for gases are greater than for liquids and solids. So, when there is formation of a gas, Entropy increases and when there isn't, entropy decreases.

Answer:

-1.82 °C

Explanation:

Step 1: Given data

Step 2: Calculate the molality of the solution

We will use the following expression.

m = mass of solute / molar mass of solute × kg of solvent

m = 33.9 g / 58.44 g/mol × 0.578 kg

m = 1.00 m

Step 3: Calculate the freezing point depression (ΔT)

The freezing point depression is a colligative property that, for a non-dissociated solute, can be calculated using the following expression:

ΔT = Kb × m

ΔT = -1.82 °C/m × 1.00 m

ΔT = -1.82 °C

Answer:

54g of O2 reacted in the reaction

Answer:

54g

Explanation:

Answer:

Radiation

Explanation:

Sun rays shine on earth. Thats radiation.

Answer:

gas to liquid

Explanation:

think of water vapor condensing on glass when you breathe on it for a while.

Answer: Servsafe 9

Explanation:

Remove food from the surface

clean the surface

rinse the surface

sanitize the surface

allow the surface to air dry

Cups and glasses are taking too long to air dry. This could be caused by the ventilation system not working properly. The correct option is D.

A ventilation system is a mechanical device that is normally created and built to supply airflow into and out of a structure or other enclosed space. Because air is provided by a functioning ventilation system, moisture on surfaces like cups and glasses can dry more quickly.

It is possible to describe air-drying as a technique or process for removing moisture from surfaces using either heated, forceful, or dry air. Therefore, air drying aids in making the surface of goods like cups and glasses dry, or free of moisture.

Thus, the correct option is D. The ventilation system not working properly.

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The question is incomplete. Your most probably complete question is given below:

A. Incorrect timing of the wash cycle.

B. An improper use of chemical sanitizer.

C. The water temperature being too high.

D. The ventilation system not working properly.

Answer:

0.02088M of EDTA

Explanation:

The Ca²⁺ is chelated in presence of EDTA in a relation 1:1, when there is no free Ca²⁺ the eriochorme black T change its colour showing endpoint.

Thus, we need to find final concentration of Ca²⁺ solution and, thus, we can find concentration of the EDTA solution:

Molarity Ca²⁺ solution:

0.2191g * (1mol / 40.08g) = 0.005467 moles of Ca²⁺ in 250mL = 0.250L:

0.005467 moles of Ca²⁺ / 0.250L = 0.02187M

Moles of Ca²⁺ added:

0.025L * (0.02187 mol / L) = 5.467x10⁻⁴ moles of Ca²⁺ = Moles of EDTA at endpoint.

Molarity EDTA:

5.467x10⁻⁴ moles EDTA / 0.02618L = 0.02088M of EDTA

Answer:

I also have this question but see the 69 page of ur question book

Answer:

NaF, CaBr2, MgO

Explanation:

Hi! For this problem, you are going to want to look at the charges of the elements in order to write their formulas.

NaF: Na has a charge of +1 and F has a charge of -1. This means that they have a 1:1 ratio and the formula is written as such - NaF.

CaBr2: Ca has a charge of +2 and Br has a charge of -1. For this problem you want to make sure that their formal charge (the charge of the entire molecule) equals 0. This means that the negative charges need to equal the positive charges. Looking at this, you are going to need to Br ions with a charge of -1 to equal one Ca ion with a charge of +2 - CaBr2.

MgO: Mg has a charge of +2 and O has a charge of -2. This means that they have a 2:2 ratio which simplifies to a 1:1 ratio and the formula is written as such - MgO.

Hope this helps!

Answer:

86

Explanation:

The reaction that takes place is:

First we convert moles of ethanol to moles of water:

Then we convert moles of water to grams of water, using its molar mass:

So 84.6 grams of water will be produced.

The mass of water, H₂O produced when 1.6 moles of ethanol, C₂H₅OH are completely burned is 86.4 g

We'll begin by writing the balanced equation for the reaction. This is given below

C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O

From the balanced equation above,

1 mole of C₂H₅OH reacted to produce 3 moles of H₂O.

From the balanced equation above,

1 mole of C₂H₅OH reacted to produce 3 moles of H₂O.

Therefore,

1.6 moles of C₂H₅OH will react to produce = 1.6 × 3 = 4.8 moles of H₂O.

Mole of H₂O = 4.8 moles

Molar mass of H₂O = (2×1) + 16 = 18 g/mol

Mass = mole × molar mass

Mass of H₂O = 4.8 × 18

Thus, the mass of water obtained from the reaction is 86.4 g

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Answer:

A

Explanation:

hope it helps

Answer:

A

Explanation:

I got right

Answer:

fluorine

Explanation:

has the highest electronegativity?

Answer:

Roman numeral notation indicates charge of ion when element commonly forms more than one ion. For example, iron(II) has a 2+ charge; iron(III) a 3+ charge.

Explanation:

Answer:

2.

a.Sodium bromide

b. Magnesium dichloride

c. Lithium iodide

not sure about 3 or 4 sry

Answer:

I'm not going to give you notes but I'm going to give you a tip for notes take what you think is the most important thing about the text and basically paraphrase it into your own words if that helps

Answer:

Solid

Explanation:

In solid there are strong intermolecular forces present as compared to liquid and gas. This is why solid are in more packed form as compared to liquid and gas. In liquid and gas intermolecular forces are week that's why molecules are away from each other and occupy more space.

Properties of gases:

Molecule of gases randomly move everywhere and occupy all available space.

Gases don't have definite volume and shape and take the shape and volume of container in which it present.

Their densities are very low as compared to the liquid and solids.

Gas molecules are at long distance from each other therefore by applying pressure gases can be compressed.

The very weak inter molecular forces are present between gas molecules.

Properties of Liquid:

Liquid have definite volume but don't have definite shape.

Their densities are high as compared to the gases but low as compared to the solids.

In liquid, molecules are close to each other and have greater inter molecular forces as compared to the gas molecules.

Properties of solids:

Solids have definite volume and shape.

In solids molecules are tightly pack and very close to each other.

Their melting and boiling point are every high.

The densities of solids are also very high as compared to the liquid and gas.

There are very strong inter molecular forces are present between solid molecules.

Answer:

A: Solid

Explanation:

Correct with Acellus

Explanation:

Elements in same row (i.e, from left to right) have the same number of electron shells.

Moles of NO formed : 0.833

Given

2.5 moles of NO2

Required

moles of NO formed

Solution

Reaction

3 NO₂(g) + H₂O(l) = 2 HNO₃(aq) + NO(g)

The reaction coefficient in a chemical equation shows the mole ratio of the compounds in the reactants and products

From the equation, mol ratio of NO₂ and NO = 3 : 1, so moles of NO :

[tex]\tt moles~NO=\dfrac{1}{3}\times 2.5\\\\moles~NO=0.833[/tex]

Answer:

Chemistry deals with matter, and there is a tremendous variety of matter in the universe. The behavior of matter depends on the type of elements that are present and on the structure of those elements—how they are connected to make a molecule. In this exercise, you will evaluate some representative models to develop the rules used to classify a compound, to predict the formula of a compound, and to name the compound. This exercise is just the beginning of the work needed to be done to master the rules of writing formulas and nomenclature. Your textbook has tables of the names and formulas of common cations and anions, and discusses the rules of nomenclature in detail. You will need to spend some time with this material, as the formal rules of nomenclature may not be presented in lecture, although they will certainly be used in discussions of Lewis structures and reaction chemistry.

Explanation:

In a covalent compound, valence electrons are shared between the two atoms in the bond. These can be evenly shared (covalent bond) or unevenly shared (polar covalent bond). In an ionic bond, electrons are localized to one of the atoms (giving it an overall negative charge), while the other atom has an overall positive charge. The difference in electronegativity between the two atoms in the bond can help predict whether the bond is likely to be ionic, covalent, or polar covalent, as can the type of atoms involved (metals or non-metals). A bond with two identical atoms is always pure covalent, while a covalent bond with two different atoms is likely to be polar covalent.

Answer:

B

Explanation:

The second one is not balanced correctly.

2 NaOH + 2HNO3 → 2NaNO3 + 2 H20

I didn't notice this before but it can be balanced without the twos.

 NaOH + HNO3 → NaNO3 +  H20

It was still wrong. It needed to have the twos removed, not 2 more added. Adding two more isn't wrong, but it should be balanced without 2s if at all possible.

I hope it is helpful for ........

Answer:

Revolution of the earth around the sun in its own orbit. A complete revolution of the earth is a year equal to 365 days

Explanation: