Answer this for 100 points.

Even a small sample of matter may contain millions and millions of atoms, molecules or ions. To represent these entities the unit mole is used. The number of moles in 0.800 g of CaCl₂ is

One mole of a substance is defined as that amount of it which contains as many particles or entities as there are atoms in exactly 12 g of Carbon - 12 is called the mole.

The equation which is used to calculate the number of moles is:

Number of moles (n) = Given mass / Molar mass

The mass of one mole of molecules of a substance is called the molar mass.

Here the given mass of CaCl₂ is 0.800 g and the molar mass is 110.98 g/mol. Then,

n = 0.800 g / 110.98 g / mol = 0.0072 mol

Thus the number of moles is 0.0072 mol.

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Answer:

C

Explanation:

Electrons are negatively charged with a charge of -1e. They can move between atoms while protons stay in the atom.

Answer:

I can't draw but you could draw 2 electrons in the first orbit and 3 electrons in the second orbit.

Explanation:

Answer:

Your talking about this correct?

Explanation:

The heat released by reaction : C) -8870 J

Given

1.008 g of hydrogen

500.00 g water

The temperature rises 25.00 °C to 29.24 °C

Required

energy required

Solution

Q absorbed by water :

Q = m.c.Δt

Q = 500 g x 4.18 J/g C x (29.24-25)

Q = 8870.08 J

The reaction to produce HCl is an exothermic reaction (releasing heat), so that Q is negative

Q water = -Q HCl = -8870.08 J

Answer:

0.625

Explanation:

i hope this is correct! and that it helps!! c:

Answer:

b.a convex lens forms a smaller,real image.

Answer:

"The number of air molecules above a surface determines air pressure. As the number of molecules increases, they exert more pressure on a surface, and the total atmospheric pressure increases. By contrast, if the number of molecules decreases, so too does the air pressure."

Answer:

The water cycle, also known as the hydrologic cycle or the hydrological cycle, describes the continuous movement of water on, above and below the surface of the Earth. The mass of water on Earth remains fairly constant over time but the partitioning of the water into the major reservoirs of ice, fresh water, saline water and atmospheric water is variable depending on a wide range of climatic variables. The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere, by the physical processes of evaporation, condensation, precipitation, infiltration, surface runoff, and subsurface flow. In doing so, the water goes through different forms: liquid, solid (ice) and vapor. Hope this helps, mark as brainliest please!

Answer:yeet

Explanation:more yeet

Answer:

stationary is the answer

Explanation:

hope this helps u

Answer:

i dont no......

Explanation:

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Answer: It is B

Explanation:

EAZYYYY

Answer:

A. manganese change from +7 to +2

Explanation:

Reduction means a gain of electrons, which means the oxidation number will go down or the charge goes down basically or become more negative charge. On the left, Mn has +7 in MnO4-. On the right, it has 2+, so it has been reduced.

Answer:

5%

Explanation:

Given parameters:

Mass of calcium chloride  = 5g

Mass of water  = 95g

Unknown:

Mass percent of calcium chloride in solution  = ?

Solution:

The mass percentage is the mass of the solute component divided by the total mass of the mixture multiplied by 100%.

So;

Mass of mixture  = mass of calcium chloride + mass of water  = 95g + 5g  = 100g

Mass percentage of calcium chloride  = [tex]\frac{5}{100}[/tex] x 100  = 5%

On the surface, weathering and erosion break down the igneous rock into pebbles, sand, and mud, creating sediment, which accumulates in basins on the Earth's surface. As successive layers of sediment settle on top of one another, the sediment near the bottom is compressed, hardens, and forms sedimentary rock.

The volume of O₂ : 21 L

Given

8.7 grams of C₂H₄

Required

Volume O₂

Solution

Reaction

C₂H₄ + 3 O₂ ⇒ 2 CO₂ + 2 H₂O

mol C₂H₄(MW= 28 g/mol) :

= mass : MW

= 8.7 g : 28 g/mol

= 0.311

From the equation, mol  O₂ :

= 3/1 x mol C₂H₄

= 3/1 x 0.311

= 0.933

At STP, 1 mol gas=22.4 L, so for 0.933 mol :

= 0.933 x 22.4 L

= 20.899 L ≈ 21 L

Explanation:

it is the one you have selected because it is the only solid one

Answer:

Explanation:

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Answer:

See explanation

Explanation:

For SCl2

S = 2.8, Cl = 3.16 difference = 0.4 polar

H2S

H = 2.2  S= 2.8  difference = 0.6  polar

CF4

C = 2.55,  F= 3.98 difference = 1.43

This compound is nonpolar irrespective of the difference in electronegativity because the molecule is symmetrical

PCl5

P= 2.19,  Cl= 3.16  difference = 0.97

This compound is nonpolar irrespective of the difference in electronegativity because the molecule is symmetrical

CH4

C = 2.55    H = 2.2    difference = 0.35 the molecule is nonpolar

CaBr2

Ca= 1    Br= 2.96  difference = 1.96

The compound is not just polar but ionic in nature due to large electronegativity difference between the bonding atoms

SF2

S = 2.8   F= 3.98     difference = 1.18

The molecule is polar

CO2

C= 2.55    O= 3.44  difference = 0.89

This compound is nonpolar irrespective of the difference in electronegativity because the molecule is symmetrical

NH3

N= 3.04     H = 2.2    difference =0.84

The molecule is polar

NaS

Na= 0.93   S = 2.8    difference = 1.87

The compound is not just polar but ionic in nature due to large electronegativity difference between the bonding

Answer:

Total

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125 grams

Answer:

Mass = 5.92 g

Explanation:

Given data:

Volume of O₂ = 4.15 mol

Temperature and pressure = standard

Mass in gram = ?

Solution:

The given problem will be solve by using general gas equation,

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K  

T = temperature in kelvin

By putting values,

1 atm × 4.15L = n ×0.0821 atm.L /mol.K × 273.15 k

4.15 atm.L = n ×22.43 atm.L /mol

n = 4.15 atm.L / 22.43 atm.L /mol

n = 0.185 mol

Mass in gram:

Mas = number of moles × molar mass

Mass = 0.185 mol ×32g/mol

Mass = 5.92 g

Answer: The pressure in atmospheres is 0.674 in the container if the temperature remains constant.

Explanation:

Boyle's Law: This law states that pressure is inversely proportional to the volume of the gas at constant temperature and number of moles.

[tex]P\propto \frac{1}{V}[/tex]     (At constant temperature and number of moles)

[tex]P_1V_1=P_2V_2[/tex]  

where,

[tex]P_1[/tex] = initial pressure of gas  = 205 kPa

[tex]P_2[/tex] = final pressure of gas = ?

[tex]V_1[/tex] = initial volume of gas  = 4.0 L

[tex]V_2[/tex] = final volume of gas = 12000 ml = 12 L    (1L=1000ml)  

[tex]205\times 4.0=P_2\times 12[/tex]  

[tex]P_2=68.3kPa=0.674atm[/tex]        (1kPa=0.0098atm)

Therefore, the pressure in atmospheres is 0.674 in the container if the temperature remains constant.

Answer:

P2=68.33 mm Hg

Explanation:

P1V1=P2V2

PLUG IN

CONVERT mL TO L (12000mL=12L)

(205)(4)=(P2)(12)

DIVIDE BOTH SIDES BY 12

P2= 68.33 kPa

Answer:

Green chemistry

Explanation:

Green chemistry is the design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances. Green chemistry applies across the life cycle of a chemical product, including its design, manufacture, use, and ultimate disposal(EPA, 2017).

Green chemistry, also called sustainable chemistry, is an area of chemistry and chemical engineering focused on the design of products and processes that minimize or eliminate the use and generation of hazardous substances(wikipedia).

Thus, any research in chemistry geared towards waste reduction(such as  more efficient methods of paper recycling) and recycling of other materials as well as placing less demands on the natural sources of materials is known as green chemistry or sustainable chemistry.

Answer:

2FeCl2+Cl2→2FeCl3

Explanation: