Chromium(III) oxide reacts with hydrogen sulfide (H2S) gas to form chromium(III) sulfide and water: Cr2O3(s) + 3H2S(g) → Cr2S3(s) + 3H2O(l) To produce 156 g of Cr2S3, (a) how many moles of Cr2O3 are required? mol (b) how many grams of Cr2O3 are required? g

Answer:

Image result for how do you convert wavelength to frequency?

How do you calculate energy from wavelength?

Convert your wavelength into meters.

Divide the speed of light, ~300,000,000 m/s, by the wavelength in m. This gives you the wave's frequency.

Multiply the frequency by Planck's constant, 6.626 x 10-34. The result is the waves energy in joules (J).

Explanation:

Answer:

NO

Explanation:

It would be difficult to plot a line of best fit on the scattered graph of the activities of metal blocks as the activities would almost be the same horizontally on the graph and an attempt to draw/determine an intercept will be almost impossible.  The line of best fit is usually drawn to determine the relatedness/correlation of the variables.

Drawing intercept for the activities of the liquid is easier because a line of best fit can be easily placed between the clustered liquid activities on the scattered plot.

Answer: See below

Explanation:

In this problem, conversion factors are very important. In the second conversion, you wrote 1 kg=0.001 g. This is incorrect. It should be 1 kg=1000g. Otherwise, the rest is correct. Make sure to have correct conversions. The answer will be correct.

Answer:

72 million because they needed to raise cash for its development

Explanation:

It is a known fact that at lunch Ethereum had only 72 million tokens in existence back in July 2015. In other to develop the Blockchain network further, the founder, Vitalik Buterin organized a fundraising event around July and August 2014.

Fast forward to the year 2020, Ether now has a total supply of about 112 million.

Answer:

F.p   ≈  - 66.16⁰c

B.p  ≈ 59.1⁰c

Explanation:

Normal boiling point = 61.2⁰c

Normal freezing point = -63.5⁰c

Kb = 3.63⁰⁰ c/m

Kf = 4.70⁰ c/m

molar mass = 253.8 g/mol

solvent = 350 g = 0.35 kg

calculate The new freezing point and Boiling point

First we have to find the molality = number of moles / solvent in kg

= 0.198 / 0.35 = 0.5657 M

Hence the new freezing point can be calculated as

Normal freezing temp -  new freezing temp = Kf * molality

= -63.5 - F.p = 4.7 * 0.5657

F.p = -63.5 - 2.6588 ≈  - 66.16⁰c

Boiling point

Normal boiling point - new boiling point = Kb * molality

= 61.2 - B.p = 3.63 * 0.5657

B.p = 61.2 - 2.0535 ≈ 59.1⁰c

Answer:

Because both CaCl2 and CaBr2 both contain elements (Chlorine and Bromine) from the same group (group 7)

Explanation:

Elements are placed into different groups in the periodic table. Elements in the same group are those that have the same number of valence electrons in their outermost shell and as a result will behave similar chemically i.e. will react with other elements in the same manner.

Chlorine and Bromine are two elements belonging to group 7 of the periodic table. They are called HALOGENS and they have seven valence electrons in their outermost shell. Hence, when they form a compound with Calcium, a group two element, these compounds (CaCl2 and CaBr2) will possess similar properties because they have elements that are from the same group (halogen group).

The compounds of [tex]\rm CaCl_2[/tex] and [tex]\rm CaBr_2[/tex] have similar chemical properties as they are constituted of elements belonging to the same group.

The compounds with the elements belonging to the same group have similar chemical properties. It has been given that the chemical properties of elements have been dependent on the number of valence electrons.

The given compounds have been calcium chloride and calcium bromide. The calcium has been the same cation in the compounds however, the anions are different.

The anion Cl and Br both belongs to group 17 and have 7 valence electrons. Thus, the compounds have been possessing similar chemical properties.

Thus, calcium chloride and calcium bromide are more likely to have similar chemical properties as they have elements belonging to the same group.

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Answer:

The number of ATP molecules produced during the anaerobic phase of cellular respiration is 32 ATP.

Explanation:

Actually it's 36 ATP

8 from glycolysis

6 from pyruvate

24 from Krebs cycle

So total are 38 ATP but 2 ATP are consumed during glycolysis so total will be 36.

The correct answer is 1030 km

Explanation:

The distance a body such as a submarine travels depends on two main variables the time of the movement and the speed. Indeed, to calculate the distance it is possible to use the formula d = s x t. The process to calculate the distance of the submarine journey is shown below:

Distance in the first part of the journey:

It is known during the first part of the journey the submarine traveled 5 hours at a speed of 106 km/h

Distance = speed × time

D = 106 km/h × 5 h

D = 530 km

Distance in the second part of the journey:

During the remaining 4 hours (the first part took 5 hours and the total time traveled were 9 hours) the speed was 125km/h. Now, let's calculate the distance covered during this part of the journey

Distance = speed × time

D= 125 km/h × 4 h

D= 500 km

Total distance:

Finally, add both distances to know the total distance

530 km + 500 km = 1030 km

1. subtract 32 from 57 (57-32)

2. multiply 5/9 by (57-32)

3. equation: (57-32)×5/9

Answer:

14°C

Explanation:

Temperature is the degree of hotness or coldness of an object. It is measured using an instrument called THERMOMETER. There are different units of measuring temperature which are interconvertible. The units are Fahrenheit (°F), Celsius (°C), Kelvin (K) etc.

Answer:

adding more water to the container

Explanation: because it would cause it to soak up the fluid to created a substance again

Answer:

adding more water to the container and iflamates the cells

Explanation:

Answer:

D. all of these are chemical changes

Answer:

helium i think

Explanation:

Answer:

Density of 40 mL of liquid that has a mass of 20 g = 20 / 40 = 0.5 g / cc

Answer:

Density= mass/volume

Density= 20/40

Density= 0.5g/mL

Answer:

d) Llanos

Explanation:

Answer:

D . Llanos

Explanation:

Answer:

46.875

Explanation:

P.E=MGH

7500=16*10*h

7500=160h

h=7500/160

h=46.875

Answer:

CH3CH2NH3+/CH3CH2NH2 would have the largest pKa

Explanation:

To answer this question we must know Kb of CH3CH2NH2 is 5.6x10⁻⁴, and for C6H5NH2 is 4.0x10⁻¹⁰. And the CH3CH2NH3+ and C6H5NH3+ are related with these substances because are their conjugate base. That means:

pKa of  CH3CH2NH3+ =  CH3CH2NH2;  C6H5NH3+ =  C6H5NH2

Also, Kw / Kb = Ka

Thus:

pKa of CH3CH2NH3+/CH3CH2NH2 is:

Kw / kb = Ka = 1.79x10⁻¹¹

-log Ka = pKa

pKa = 10.75

pKa of C6H5NH3+/ C6H5NH2 is:

Kw / kb = Ka = 2.5x10⁻⁵

-log Ka = pKa

pKa = 4.6

That means CH3CH2NH3+/CH3CH2NH2 would have the largest pKa

Answer:

0.027 ml

Explanation:

[tex]1\:cl = 10\:ml\\0.0027 \: cl = x\:ml[/tex]

Cross Multiply

[tex]x = 0.027 \:ml[/tex]

Matter are anything that is made up of atoms. The quantity of matter can be observed only on the basis of mass and volume calculation. Therefore, the correct option is option C.

Matter is a substance that has some mass and can occupy some volume. The matter is mainly used in science. Matter can be solid, liquid or gas.

Matter is anything that is made up of atoms. Anything around us that can be physically seen and touched are matter. Ice, water and water vapors are example of matter.

Cytosol is the liquid medium contained within a cell. The cytosol is a component of the cytoplasm. Out of given option cytosol  has the greatest concentration of potassium ions. The cytoplasm does not include the nucleus.

Therefore, the correct option is option C.

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Answer:

it moves faster when heated

Answer:

the answer is faster

Explanation:

why because water moves faster when heated

Answer:

Yes, it is possible.

Explanation:

A diprotic acid is an acid that can release two protons. That's why it is called diprotic.

Monoprotic → Release one proton, for example Formic acid HCOOH

Triprotic → Releases three protons, for example H₃PO₄

Polyprotic → Release many protons, for example EDTA

it is a weak acid.

In the first equilibrum, it release proton, and the second is released in the second equilibrium. So the first equilibrium will have a Ka1

H₂A  +  H₂O  ⇄  H₃O⁺  +  HA⁻                Ka₁

HA⁻  +  H₂O  ⇄  H₃O⁺  +  A⁻²               Ka₂

The HA⁻ will work as an amphoterous because, it can be a base or an acid, according to this:

HA⁻   +  H₂O  ⇄  H₃O⁺   + A⁻²      Ka₂

HA⁻   +  H₂O  ⇄  OH⁻   + H₂A       Kb₂

Answer:

See explanation

Explanation:

(a)

From the data provided;

Mass of methanol =11.0 g

Mass of solvent (H2O) =100 g = 0.1 kg

Molar mass of CH3OH =32.04 g/mol

Number of moles of solute = 0.343 mol

molality(m) of methanol = 3.43 m

Also,

Mass of ethanol =22.0 g

Mass of solvent (H2O) =200 g = 0.2 kg

Molar mass of C2H5OH =46.068 g/mol

Number of moles of solute = 0.477 mol

molality(m) of ethanol= 2.38 m

The greater the concentration of a solution, the higher the freezing point of solvent will be depressed. Therefore, higher molality, leader to a greater decrease of the freezing point.

Therefore, the freezing point of methanol CH3OH/H2O is lower than the freezing point of ethanol.

b)

Mass of solvent = 1 kg

Mass of water = 20g or 0.02 Kg

Molar mass of water = 18 gmol-1

Number of moles of solute = 20g/18 gmol-1 = 1.11 moles

Molality= 1.11 moles/1 kg = 1.11 m

Also;

Mass of ethanol = 20 g = 0.02 kg

Mass of solvent = 1.00 Kg

Molar mass of solute = 46 gmol-1

Number of moles of solute = 20g/ 46 gmol-1 = 0.43 moles

Molality= 0.43 moles/ 1 kg = 0.43 m

The greater the concentration of a solution, the higher the freezing point of solvent will be depressed. Therefore, higher molality, leader to a greater decrease of the freezing point.

Therefore, the freezing point of water H2O/CH3OH is lower than the freezing point of ethanol.

Answer:

The answer is Sulphur and Nitrogen ion

Answer:

Density, d = 1.779 g/cm³

Explanation:

The density of a material is given by its mass per unit volume.

Here, height of a piece of magnesium cylinder, h = 5.62 cm

Its diameter, d = 1.34 cm

Radius = 0.67 cm

Volume of he cylinder,

[tex]V=\pi r^2 h\\\\\text{Putting the value of r and h, we get :}\\\\V=(\pi \times (0.67)^2\times 5.62)\ cm^3[/tex]

[tex]d=\dfrac{m}{V}\\\\d=\dfrac{14.1\ g}{(\pi \times (0.67)^2\times 5.62)\ cm^3}\\\\d=1.779\ g/cm^3[/tex]

So, the density of the sample is 1.779 g/cm³.

Answer:

C. The ratio of the substances coefficients equal the ratio is the number of moles

Explanation:

The ratio of the substances' coefficients equals the ratio of their

number of moles. Hence, option C is correct.

A mole is defined as 6.02214076 × [tex]10^{23}[/tex]of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.

Mole ratios are used as conversion factors between products and reactants in many chemistry problems.

The mole ratio may be determined by examining the coefficients in front of formulas in a balanced chemical equation.

Also known as the mole ratio is also called the mole-to-mole ratio.

Hence, option C is correct.

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Answer:

69.7% is percent yield

Explanation:

Based on the reaction:

3Ca(NO3)2(aq) + 2Na3PO4(aq) → Ca3(PO4)2(s) + 6NaNO3(aq)

2 moles of Na3PO4 react producing 6 moles of NaNO3.

As 24.2 moles of Na3PO4 react, theoretical moles of NaNO3 produced are:

24.2 moles Na3PO4 * (6 moles NaNO3 / 2 moles Na3PO4) =

72.6 moles of NaNO3

As there are produced 50.6 moles of NaNO3, percent yield is:

50.6 moles NaNO3 / 72.6 moles NaNO3 =

Answer:

Self-reduction is a reaction in which no external reducing agent is required. It is called self-reducing because copper oxide itself reduced the copper sulfide to give copper and sulfur dioxide.