List the 5 characteristics of a
physical change

Answer:

0.2193 μm

Explanation:

The reaction showing the Photodissociation of ozone (O3) is given below as:

           O₃         +        hv   -------------------------->      O₂         +       O⁺  

H°        (142.9)                                                         (0)                  (438kJ/mol).

The first thing to do here is to determine the change in the enthalpy of the total reaction, this can be done by subtracting the change in the enthalpy of the reactant from the change in enthalpy in the product. Hence, we have:

ΔH° = [438 kJ/mol + 247.5 kJ/mol] - (142.9) = 542.6 KJ/mol.

This value, that is 542.6 KJ/mol will then be used in the determination of the value for the maximum wavelength that could cause this photodissociation.

Therefore, the maximum wavelength could cause this photodissociation ≤ h × c/ E = [ 1.199 × 10⁻⁴]/ 542.6 = 2.193 × 10⁻⁷ =  0.2193 μm

Answer:

I believe the answer is three: Lead, sulfur, and oxygen

Explanation:

Answer:

-122 J/K

Explanation:

Let's consider the following balanced reaction.

N₂(g) + 2 O₂(g) ⇒ 2 NO₂(g)

We can calculate the standard reaction entropy (ΔS°) using the following expression.

ΔS° = Σ ηp × Sf°p - Σ ηr × Sf°r

where,

ΔS° = 2 mol × 240.06 J/K.mol - 1 mol × 191.61 J/K.mol - 2 mol × 205.14 J/K.mol

ΔS° = -121.77 J/K ≈ -122 J/K

Answer:

true

Explanation:

hope this answer helps :)

Answer:

true

Explanation

vitamins and minerals are protective foods

The temperature = T = 1.29 K

Given

n = 7.5 moles

P = 107.5 kPa = 1,0609425 atm

V = 748 cm³ = 0.748 L

Required

Temperature

Solution

Ideal gas law :

PV = nRT

T = (PV)/(nR)

T = (1,0609425 x 0.748)/(7.5 x 0.08205)

T = 1.29 K

Answer:

Explanation: C

Answer:

a)there would be no reaction

Explanation:

The activity series of metals has many functions. The one applicable to this problem is that it can be used to determine whether a reaction will occur or not. Also, based on the positions of metals in the series, we can know how reactive a metal is compared to another.

In a single displacement reaction, a metal replaces another metal based on their position on the activity series. Metals that are higher in the series are generally more reactive than others below them and so will displace them.

Would aluminum replace magnesium to form a new compound or would there be no reaction?

Magnesium is higher than aluminum in the activity series. Therefore it is more reactive than aluminum. No reaction will occur.

Explanation:

Acid rain is linked to both natural and man-made sources. Nitrogen oxides are formed through the extreme heating of air when a thunderstorm produces lightning. ... For this reason, acid rain is considered a global problem

Answer:

Acid rain is a global concern.

Explanation:

The effects of acid rain have reached dramatically mainly in the industrialized countries which fall on global ecology.

Answer:

130g

Explanation:

For every mole of a substance, there is a molar mass that coincides with the masses on the periodic table. For one mole of H2O, you would add the molar masses of the two hydrogen atoms and the oxygen atom to get 18.016g. You would then take this molar mass and multiple it by the amount of moles present (7.4) to get 133.3184g

From here, you would round to the significant figures to get 130g

Answer:

Amount of insulation surrounding the wire

Answer:

Energy is passed up a food chain or web from lower to higher trophic levels.

Explanation:

However, generally only about 10 percent of the energy at one level is available to the next level. This is represented by the ecological pyramid in Figure below.

Answer:

generally only about 10 percent of the energy at one level is available to the next level

Explanation:

thank you

Answer:

The law of conservation of mass states that in a chemical reaction mass is neither created nor destroyed. ... The carbon atom changes from a solid structure to a gas but its mass does not change. Similarly, the law of conservation of energy states that the amount of energy is neither created nor destroyed.

The correct statement is 'the mass of reactants is equal to the mass of the products'.

Explanation:

So, from this we can conclude that the from the given statements the correct statement is 'the mass of reactants is equal to the mass of the products'.

Learn more about 'Law of conservation of mass ' here:

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Answer:

if you ask yahoo answers it will tell you

Explanation:

hope i helped

Answer:

-2856

-792

endothermic, exothermix, exothermic, endothermic

no

Explanation:

Answer:

a. 105

b. 76.4

c. 0.04

d. 4.000

Explanation:

Question a. has three significant figures

Question b. has three significant figures

Question c. has one significant digit (only the 3 is significant in the question, zeros are only significant if they are trailing with the presence of a decimal point or in between two non-zero numbers)

Question d. has four significant figures

Answer:

the answer is nitrogen

Explanation:

u can right this for explain your answer-

( nitrogen is unreactive

nitrogen doesn't support burning )

orrrrr

(contains no oxygen

all the other jars contain oxygen)

The mass percent of MgCO3 in the mixture is 18.33%.

In the mixture we have:

MgCO3 + (NH4)2CO3 but the percentage by mass of carbonate CO3 is 64.16%

Hence,

Total mass = 100 grams

Let the mass of MgCO3 = x grams

Let the mass of (NH4)2CO3 = y grams

So we have,       x + y = 100 ------------(1)

If the mass of CO3 = 64.16% = 64.16 g

But the molar mass of CO3 = 60 g/mol

Then,

Number of moles of CO3 = 64.16 g/60 g.mol-1 = 1.069 moles

Since we obtained the number of moles of CO3 from CO3 in MgCO3 and (NH4)2CO3.

Therefore,

moles MgCO3 + moles (NH4)2CO3 = 1.069

mass of MgCO3 present/molar mass MgCO3 + mass of (NH4)2 CO3 present/molar mass = 1.069

So,

x/84 + y/96 = 1.069---------(2)

From equation 1;

 y =100 - x  

x/84 + (100-x)/96 = 1.069

x = 18.33 g

Mass of MgCO3 = 18.33 g

Mass percent of MgCO3 = 18.33%

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Answer:

1) SO₄ ²⁻ : (+6)

  H₂S : (-2)

Explanation:

a) Sulfate reducers are widespread in muds and other sediments, water-logged soils, etc., environments that contain SO₄ ²⁻ and become anoxic as a result of microbial decomposition.

Sulfate (SO₄ ²⁻), the most oxidized form of sulfur (+6), is reduced by these

sulfate-reducing bacteria. The end product of sulfate reduction is hydrogen sulfide, H₂S, (oxidation number -2) an important natural product that participates in many biogeochemical processes. The H₂S they generate is responsible for the pungent smell (like that of rotten eggs) often encountered near coastal ecosystems. When sulfate-reducing bacteria grow, the H₂S formed from SO₄ ²⁻ reduction combines with the ferrous iron to form black, insoluble ferrous sulfide, which is not toxic. This is important for the conservation of the environment.

b) The net ionic equation under acidic conditions is:

              4 H₂ + SO₄²⁻ + H⁺ → HS⁻ + 4 H₂O

    Global reaction:  SO₄²⁻ + 2H⁺ → H₂S + O₂

Answer:

Animals obtain energy from the food they consume , using that energy to maintain body temperature and perform other metabolic functions. Glucose, found in the food animals eat ,is broken down during the process of cellular respiration into energy source called ATP.

reaction

CH₄  +  2 O₂  ==>  CO₂  + 2 H₂O   (Equal)

first, let's count the mole of H₂O that formed

mole H₂O = (coefficient of H₂O / coefficient of CH₄) x mole CH₄

mole H₂O = (2/1) x 6,35 mole

mole H₂O = 12,7 mole

so

Mass H₂O = mole H₂O x Molecular Mass

Mass H₂O = 12,7 mole x 18   ((2 x Ar H) + Ar O)

Mass H₂O = 228,6 g

Answer:

134.4 g of Mg

Explanation:

reaction:

2Mg + O2 ➡️ 2MgO

1) find the mol of MgO

mol = mass / molar mass

mass = 224 g

molar mass = 24+16 = 40

mol = 224 / 40

= 5.6 moles

2 mol = 5.6 moles

2) find the mass of Mg

mass = mol × molar mass

mol = 5.6

molar mass = 24

mass = 5.6 × 24

= 134.4 g

1.3 × 10²⁴ particles AlPO₄

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Atomic Structure

Stoichiometry

Step 1: Define

2.1 mol AlPO₄

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.

1.26462 × 10²⁴ particles AlPO₄ ≈ 1.3 × 10²⁴ particles AlPO₄

Answer:

[tex]4.5x10^{-5}\frac{kg}{L}[/tex]

Explanation:

Hello!

In this case, since the density in the international system of units is given in terms of kg for the mass and L for the volume, we need to perform a process of units conversions from mg and dL to kg and L as show below:

[tex]4.5\frac{mg}d{L}*\frac{1kg}{1x10^6mg} *\frac{10dL}{1L} \\\\4.5x10^{-5}\frac{kg}{L}[/tex]

Best regards!

Answer:

The one that's highlighted in blue is the answer

Answer:

Explanation:

EVAPERATION --- is water falling back to the earth

CONDUNSATION -- Process where water vapor is cooled

RUNOFF ---- Process where the water that falls back down to earth runs over to lakes, river, and ocean

It can take hundreds of billions of years for a red dwarf to convert all of its hydrogen completely to helium is false it takes less than 14 billion years to completely burn through its fuel.

A red dwarf is one of the smallest and coldest stars on the main sequence. As red people are the most common type of star in the Milky Way, at least in the vicinity of the Sun, but because of their low luminosity, people cannot be easily observed.

In the solar core, the temperature and density are gigantic and cause nuclear fusion of hydrogen into helium. Four hydrogen atoms fuse to form a helium atom. And this fusion is an incredible way to produce energy.

See more about red dwarf at brainly.com/question/25981690

This question is incomplete, the complete question is;

You want to plate a steel part having a surface area of 240 in² with a 0.002-in thick layer of silver.

The atomic mass of silver is 107.868 g/mol .

The density of silver is 10.49 g/cm³.

How many atoms of silver are required?

Answer:

4.6 × 10²³ atoms of silver are required

Explanation:

Given the data in the question;

first, we determine the volume of silver layer  

volume of silver layer = surface area × thickness

we substitute

volume of silver layer =  240 in² × 0.002-in = 0.48 in³

we know that 1 in³ = 16.387 cm³

so, volume of silver layer  = 0.48 × 16.387 = 7.87 cm³

Next we calculate mass of silver;

⇒ density × Volume

mass of silver = 10.49 g/cm³ × 7.87 cm³ = 82.5563 g

Now, number of atoms of silver are required will be;

Number of atoms = (mass/atomic mass) × Avogadro number

we know that A.v no. is 6.02214 × 10²³ mol⁻¹

so

Number of atoms = (82.5563 g / 107.868 g/mol . ) × 6.02214 × 10²³ mol⁻¹

= 0.7653 × 6.02214 × 10²³

= 4.6 × 10²³ atoms

Therefore; 4.6 × 10²³ atoms of silver are required

The percent error of Chemistry student : 7.4%

Given

40 °C measurement

Required

The percent error

Solution

% Error : difference between the theoretical value and the actual value

or

% Error : Absolute Error / Accepted Value

Absolute Error = Measured Value - Accepted Value

% Error for Chemistry student  :

1. Subtract the measurement value with the accepted value

= 40 °C - 43.2 °C

= -3.2 °C

2. Divide by the accepted value, and multiply by 100

= |-3.2/43.2| x 100%

= 7.4%

Answer:

a

Explanation:

Answer:

A

Explanation:

Answer:

19. 1, 2, 3, 4, 5, 6, 7, 8

20. Li=1+, Be=2+, B=3+, C=4+

21. N=3-, O=2-, F=1-

Explanation: