The percentage by mass of oxygen in a compound containing potassium, chlorine, and oxygen was determined experimentally. The technique used follows. solid (KClo compound is weighed. Then it is heated in a crucible. The The solid decomposes to produce oxygen gas and a salt. Because the oxygen escaping, mass of the original solid decreases. From the mass of oxygen lost and mass is the the percentage by mass of oxygen in of the original the original compound is determined. KClyo. (s) salt (s) O (g A student performs five trials and determines the following by mass of oxygen in the compound (KCLO) by mass of oxygen Trial in the compound 38.933 38,940 38,892 38.900
a. Determine the average experimental percentage oxygen in the compound. by mass of 30.933
b. If the actual value of the percentage by mass ofoxygen in this compound is 39.13 determine the percentage error.

Answer:

B

Explanation:

Most planets in the solar system don't have water. Helium and hydrogen are two of the many gasses in planets. Therefore, B is the best answer.

Answer:

d. a brittle solid.

Explanation:

Hello!

In this case, since cesium fluoride is widely known as an ionic compound due to the large electronegativity difference, it is possible to discard a. due to its crystalline structure, b. because conducting solids are metals, c. because ionic compounds are not likely to be gases and e. because even when it is soluble in water, the problem is not referring to an aqueous solution; therefore, the answer is d. a brittle solid.

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Answer:

The same instrument must be used to measure the unknown solution as was used to measure the known (standard) solutions that were used to create the calibration curve.

The analyte in the unknown solution must be the same analyte (or type of analyte) that is present in the known (standard) solutions that were used to create the calibration curve.

Domain and range restrictions must be observed.

Explanation:

Calibration curves are tools necessary in understanding the instrumental response for any analyte.

A calibration curve is obtained by preparing a set of  standard solutions with known concentrations of the analyte. The instrument response for each concentration is measured  and plotted against the concentration of the standard solution. The linear portion of this plot may be used to determine the unknown concentration of a sample of the analyte.  

The equation of the best-fit line is  used to determine the concentration of the unknown sample.

Answer:

Explanation:

Mol weight of HCl = 36.5

.90 g of HCl = .90 / 36.5 mole = .02465 mole

HCl      =    H⁺        +      Cl⁻

1 mole     1 mole

1 mole of HCl gives 1 mole of H⁺

.02465 mole of HCl will give .02465 mole of H⁺

.02465 mole of H⁺ in 5 litre soln

concentration of H⁺ =  .02465 / 5 = 4.93 x 10⁻³ M

pH = - log ( 4.93 x 10⁻³ )

= 3 - log 4.93

= 3 - .693

= 2.307

= 2.31

NaOH :

Mol weight of NaOH  = 40

.50 g of HCl = .50 / 40 mole = .0125 mole

NaOH     =    Na⁺        +      OH⁻

1 mole     1 mole

1 mole of NaOH gives 1 mole of OH⁻

.0125 mole of NaOH will give .0125 mole of OH⁻

.0125 mole of OH⁻ in 4 litre soln

concentration of OH⁻ =  .0125 / 4 = 3.125 x 10⁻³ M

pOH = - log ( 3.125 x 10⁻³ )

= 3 - log 3.125

= 3 - .495

= 2.505

pH = 14 - pOH

= 14 - 2.505

= 11.495 .

= 11.50

Answer:

A: Helium or Hydrogen

Explanation:

Terrestrial planets are the 4 inner most planets of the solar system which are mercury, venus, earth, Mars, while the giant planets are the 4 outer most which are Jupiter, Saturn, Uranus and Neptune.

Now, these outer most ones are the surface ones and are surrounded primarily by layers of hydrogen and helium gases.

Answer:

b

Explanation:

Combinations between two strands:

T - A

A - T

C - G

G - C

(so if one strand has A for example, then the other strand must have T in the same spot)

Bases   which are present on the other strand of DNA are TAT.

DNA or deoxyribonucleic acid is a hereditary material present in humans as well as all living beings. Almost every cell present in the body has DNA. Most DNA are located inside the cell , that is in the nucleus of the cell. But a small portion of DNA  can be found in the mitochondria of the cell as well.

The information in DNA is stored as a code which is composed of four chemical bases 1) adenine 2)guanine 3) cytosine  4) thymine . The human DNA consists of 3 billion bases . The order of of these bases determine information which is used for building and maintaining an organism.

The DNA bases can pair with each other .Adenine pairs with thymine   and guanine with cytosine to form units which are called as base pairs.Each base apart from other complementary base it also attaches itself to a sugar and a phosphate molecule.

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Answer:

0.25 of the original

Explanation:

(0.5)^(90/45)

The fraction of iron-59 after 90 days is 0.25.

Iron-59 decays following first-order kinetics. Given the half-life ([tex]t_{1/2}[/tex]) of 45 days, we can calculate the rate constant (k) using the following expression.

[tex]k = \frac{ln2}{t_{1/2}} =\frac{ln2}{45day} = 0.015 d^{-1}[/tex]

For first-order kinetics, we can find the fraction of Fe ([Fe]/[Fe]₀) after and an elapsed time (t) of 90 days, using the following equation.

[tex]\frac{[Fe]}{[Fe]_0} =e^{-k \times t } = e^{-0.015 d^{-1} \times 90 d } \approx 0,25[/tex]

The fraction of iron-59 after 90 days is 0.25.

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Answer:

Ammonia

Explanation:

Both amines and amides are structurally similar to ammonia, the difference is the introduction of a carbon into the structure.

28 mol CaF

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Atomic Structure

Stoichiometry

Step 1: Define

[Given] 1.7 × 10²⁵ molecules CaF

[Solve] moles CaF

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

Step 4: Check

Follow sig fig rules and round. We are given 2 sig figs.

28.2298 mol CaF ≈ 28 mol CaF

Answer:

0.03947 atm

Explanation:

The relationship between mmHg and atm is given as;

1 atm = 760 mmHg

x atm = 30 mmHg

Upon solving for x;

x * 760 = 30 * 1

x = 30 / 760 = 0.03947 atm

Answer:

snow is made up of a variety of mostly organic matter, including dead or dying animals and phytoplankton, protists, fecal matter, sand, and other inorganic dust.

Explanation:

I hope I helped!!

Plz mark me brainliest it would really make my day!

Answer:

I think its organic unless we are talking about this snow storm then no

Answer:

Fact: There’s only one letter that doesn’t appear in any U.S. state name

And that is Q

Explanation:

Answer:

That is the Atomic mass

Explanation:

The element symbol is S, Element name is sulfur, and

Atomic number is 16

Answer:

liquid

Explanation:

it's not plasma, solid, or gas

so I think liquid

Answer:

the answer to this question is A H202

Answer:

The answer to this is solids!

Answer:

60.88%

Explanation:

The balanced equation of the reaction is given as;

2 AgNO3 (aq) + BaCl2 (aq) → 2 AgCl (s) + Ba(NO3)2 (aq)

Since AgNO3 is in excess, the limiting reactant is BaCl2. From the reaction;

1 mol of BaCl2 produces 2 mol of AgCl

Converting to masses;

Mass = Number of mol * Molar mass

BaCl2;

Mass = 1 * 208.23 g/mol = 208.23 g

AgCl;

Mass = 2 * 143.32 g/mol = 286.64 g

208.23 g BaCl2 produces 286.64 g of AgCl

x g BaCl2 produces 7.123 g of AgCl

Solving for x;

x = 7.123 * 208.23 / 286.64 = 5.1745 g

Mass percent = Mass / Total mass of Mixture  * 100

Mass Percent = 5.1745 / 8.500 = 0.6088 * 100 = 60.88%

Answer:

Step 1 should be convert atoms to moles (n). Step 2 should be convert moles (n) to mass (m).

Step 1

Use dimensional analysis to convert the number of atoms to moles.

1 mole atoms = 6.022 × 10²³ atoms

n(Ag) = 2.3 × 10²⁴ Ag atoms × (1 mol Ag/6.022 × 10²³ Ag atoms) = 3.8193 mol Ag

Step 2

Convert the moles of Ag to mass.

mass (m) = moles (n) × molar mass (M)

n(Ag) = 3.8193 mol Ag

M(Ag) = atomic weight on the periodic table in g/mol = 107.868 g Ag/mol Ag

m(Ag) = 3.8193 mol × 107.868 g/mol = 412 g Ag = 410 g Ag rounded to two significant figures

The mass of 2.3 × 10²⁴ Ag atoms is approximately 410 g.

Explanation:

The number of moles that are present is 2.3 × 10²⁴ atoms of silver are 3.8193 moles that can be determined using Avogadro's law.

One mole:

A mole is defined as 6.022 × 10²³ of some chemical unit, be it atoms, molecules, ions, or others.

1 mole = 6.022 × 10²³ atoms

n(Ag) = 2.3 × 10²⁴ Ag atoms × (1 mol Ag/6.022 × 10²³ Ag atoms)

n(Ag) = 3.8193 mol Ag

Thus, the number of moles is 3.8193 moles.

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Answer:

1.6666666666666 is the ans bcz in each mole there r 12 grams of carbon so the ans is goingtobe 20÷12

According to the mole concept, there are 1.66 moles in 20 grams of carbon.

Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.

It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.

It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons. Molar mass has units of gram per mole . In case of molecules, where molar mass  in grams present in one mole  of atoms is its atomic mass.

Number of moles is calculated as, mass/molar mass, thus on substitution , number of moles=20/12=1.66 moles.

Thus, there are 1.66 moles in 20  grams of carbon.

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Answer:

Copper, Water, and Oxygen

Explanation:

Because they are compounds and compounds are pure substances <3

Answer: copper

Explanation: because all of the atoms that make up copper are copper i.e its not a compound or mixture. not made od molecules

Answer: the electrostatic potential energy is -3.26 × 10⁻¹⁸ J

Explanation:

Given the data in the question;

I think the value of electrostatic potential energy of calcium sulfide CaS formed will be less(more negative) than KCl because the Ca2+ and S2- ions has more charge that is +2 and -2 respectively when compared to Kcl which has +1 and -1 charge.so it will be more negative.

radius = r[tex]_{ca+2}[/tex] + r[tex]_{s-2}[/tex] = 100 + 184 = 284 pm = 2.84 × 10⁻¹⁰ m

we know that; k = 2.31 × 10⁻²⁸ J

q1 = 2  ( charge on Ca⁺² )

q2 = -2( charge on S⁻²)

so

Ep = k × q1q2/r

so we substitute

Ep = 2.31 × 10⁻²⁸ × (+2×-2) / 2.84 × 10⁻¹⁰

Ep = (2.31 × 10⁻²⁸ × -4) / 2.84 × 10⁻¹⁰

Ep = -9.24 × 10⁻²⁸ / 2.84 × 10⁻¹⁰

Ep = -3.26 × 10⁻¹⁸ J

Therefore, the electrostatic potential energy is -3.26 × 10⁻¹⁸ J

Based on the data provided, the electrostatic potential energy is -3.26 × 10⁻¹⁸ J

The electrostatic potential energy is the work done in moving the charge from infinity to that point against the electric field.

The electrostatic potential energy between any two charges q1, q2 separated by distance r is derived from Coulomb’s law and mathematically given as:

where

From the data provided:

ionic radii of Ca2+ r1 = 100 pm

ionic radii of S2– = 184 pm.

Chargeon Ca2+ = +2

Charge on S2_ = -2

From the data above, it most likely that the value of electrostatic potential energy of calcium sulfide CaS formed will be less(more negative) than KCl because the Ca2+ and S2- ions has a greater charge of +2 and -2 respectively compared to Kcl which has +1 and -1 charge.

Calculating the electrostatic potential energy, Ep:

radius = r1 + r2 = 100 + 184 = 284 pm

r = 2.84 × 10⁻¹⁰ m

k = 2.31 × 10⁻²⁸ J

q1 = 2  ( charge on Ca⁺² )

q2 = -2( charge on S⁻²)

Then:

Ep = k × q1q2/r

Substituting the values above in the equation:

Ep = 2.31 × 10⁻²⁸ × (+2 ×-2) / 2.84 × 10⁻¹⁰

Ep = (2.31 × 10⁻²⁸ × -4) / 2.84 × 10⁻¹⁰

Ep = -9.24 × 10⁻²⁸ / 2.84 × 10⁻¹⁰

Ep = -3.26 × 10⁻¹⁸ J

Therefore, the electrostatic potential energy is -3.26 × 10⁻¹⁸ J.

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Answer:

0.012 M

Explanation:

Step 1: Given and required data

Step 2: Calculate the moles (n) of solute (KCl)

We will use the following expression.

n = m/M = 0.64 g / (74.553 g/mol) = 8.6 × 10⁻³ mol

Step 3: Calculate the molar concentration (C) of the solution

The molarity is equal to the moles of solute divided by the liters of solution.

C = 8.6 × 10⁻³ mol/0.725 L = 0.012 M

Answer:

3.0g remain

Explanation:

The half-life is defined as the time required for a reactant to decrease its concentration in exactly the half of the initial amount of reactant. Having this in mind:

In one half-life, the mass will be:

24.0g / 2 = 12.0g

In two half-lifes:

12.0g / 2 = 6.0g

And in three half-lifes, the mass that remain is:

6.0g / 2 =

Answer:

Within three molecules of Ethane, it would have 6 carbon, and 18 hydrogen atoms in it.

Explanation:

Answer:

No, compound A and B are not the same compound

Explanation:

According to the law of definite proportion "every chemical compound contains fixed and constant proportions (by mass) of its constituent elements." (Encyclopedia Britannica)

We can see in the question that the ratio of flourine to sulphur in compound A is 1.18 while the ratio of flourine to sulphur in compound B is 2.37.

The two chemical compounds do not contain a fixed proportion by mass of their constituent elements therefore, they can not be same compound according to the law of definite proportions.

Answer:

5 × 10⁻³ mol

Explanation:

Step 1: Given data

Step 2: Convert "V" to dm³

We will use the conversion factor 1 dm³ = 1000 cm³.

25 cm³ × 1 dm³/1000 cm³ = 0.025 dm³

Step 3: Calculate the moles of HCl (n)

We will use the definition of molarity.

C = n/V

n = C × V

n = 0.2 mol/dm³ × 0.025 dm³ = 5 × 10⁻³ mol

Answer:

Explanation:

TiO2 + C + 2 CI2 → TiCI4 + CO2

(a)

(2.16 mol TiO2) x (2 mol CI2 / 1 mol TiO2) x ( 70.9064 g C/mol) = 306 g CI2

(b)

(2.16 mol TIO2) x (1 mol C / 1 mol TiO2) x ( 12.01078 g C/mol)n= 25.9 g C

(c)

Use the law of conservation of mass:

(2.16 mol TiO2) x ( 79.8660 g TiO2/mol) + (306 g CI2 + 25.9 g C = 504 g total.

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