Based on the context in paragraph 4 fossils refers to

Answer:

The periodic table helps organize all the elements found in the world and tells a great deal of information on each of the elements such as their atomic mass, symbol, atomic number, and more. It even is organized into groups (columns) and periods (rows). The elements in the same group mostly have similar chemical properties. In short, the periodic table is a list of the elements that make up the world around you.

Explanation:

Answer:

its electron

Explanation:

i dont have an explanation but i hope you get it right

Answer:

A. hamper

Explanation:

i did this question before.

Answer:

Improve

Explanation:

They improved Washington's rank so that he could rise to the top.

Answer:

Mass = 0.697 g

Explanation:

Given data:

Volume of hydrogen = 1.36 L

Mass of ammonia produced = ?

Temperature = standard = 273.15 K

Pressure = standard = 1 atm

Solution:

Chemical equation:

3H₂ + N₂       →      2NH₃

First of all we will calculate the number of moles of hydrogen:

PV  = nRT

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

1atm ×1.36 L = n × 0.0821 atm.L/mol.K × 273.15 K

1.36 atm.L = n × 22.43 atm.L/mol

n = 1.36 atm.L / 22.43 atm.L/mol

n = 0.061 mol

Now we will compare the moles of hydrogen and ammonia:

                 H₂         :          NH₃

                  3          :            2

                0.061     :         2/3×0.061 = 0.041

Mass of ammonia:

Mass = number of moles × molar mass

Mass = 0.041 mol × 17 g/mol

Mass = 0.697 g

the answer is mitosis

Answer: Density of methane is 0.92 g/L

Explanation:

The relation between density and molar mass is :

[tex]d=\frac{PM}{RT}[/tex]

where , d = density

P = pressure = 910 torr = 1.20 atm     (760 torr=1atm)

M = molar mass = 16 g/mol ( for methane)

R = gas constant  = [tex]0.0821Latm/Kmol[/tex]

T = temperature = 255 K

Putting the values :

[tex]d=\frac{1.20atm\times 16g/mol}{0.0821Latm/Kmol\times 255K}=0.92g/L[/tex]

Thus density of methane is 0.92 g/L

The controlled burn cause of wildfires is least likely to lead to catastrophic results. Therefore, option (C) is correct.

A controlled burn is a fire set intentionally for purposes of forest management, prairie restoration, farming, or greenhouse gas. A controlled burn refers to the intentional burning of slash, fuels through burn piles.

Controlled burning can be done during the cooler months to reduce fuel buildup and reduce the likelihood of serious hotter fires. Controlled burning enhances the germination of desirable forest trees, and exposes soil mineral layers which expand seedling vitality.

Controlled burning is also useful in agriculture as it is often referred to as slash and burns. It is one component of shifting cultivation, as a section of field preparation for planting called field burning. This technique is utilized to clear the land of any existing crop residue and kill weeds and weed seeds.

Field burning is less expensive but because it forms smoke and air pollutants, its use is not common in agricultural areas.

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Answer:

Among these statements B is the correct answer.

Answer: I'm not sure if you have a selection of choice but I think it's A. Female deer have no need for antlers.

Explanation: I mean they don't.. Even if the Male are older that doesn't stop a female deer from growing antlers.. Just flimsy one's I guess.

In an ecosystem, as the growth of antlers is controlled by genes male  male whitetail deer grow antlers but females seldom grow antlers.

Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.

Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.

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Answer:

pH

Explanation:

We define the pH of a solution as the negative logarithm of hydronium ions concentration in solution.

Thus when we want to define pH mathematically, we write;

pH = - log {H3O^+]

Where;

{H3O^+] means the concentration of hydronium ions in solution.

Answer:

178.35g

Explanation:

Molarity of a solution can be calculated using the formula:

Molarity = number of moles ÷ volume

Based on the information provided in this question, molarity (M) of the solution = 1.50 M, volume = 725 mL = 725/1000 = 0.725L, n = ?

1.50 = n / 0.725

n = 1.50 × 0.725

n = 1.0875mol

Molar mass of Na3PO4

23(3) + 31 + 16(4)

= 69 + 31 + 64

= 164g/mol

Mole = mass ÷ molar mass

1.0875 = mass/164

mass = 178.35g

Answer:

3 one

Explanation:

A is the answer! A chemical reaction always starts with the reactants and ends with a product!

Hope this helps x :)

Explanation:

The reactants are simply the substances present when a reaction begins.

Reactants are as opposed to products. The latter are substances that are present when a reaction is complete.

Reactants generally undergo chemical changes before they can form products. The chemical changes involve the breakage of old and the formation of new bonds among atoms of different elements that make up the reactants.

Reactants also need to summon an energy barrier before products can be formed. the energy barrier is known as activation energy.

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Answer: 101 moles of oxygen are contained in the tank

Explanation:

According to ideal gas equation:

[tex]PV=nRT[/tex]

P = pressure of gas = 204.047  atm

V = Volume of gas = 12.0 L

n = number of moles  = ?

R = gas constant =[tex]0.0821Latm/Kmol[/tex]

T =temperature =[tex]22.0^0C=(22.0+273)K=295K[/tex]

[tex]n=\frac{PV}{RT}[/tex]

[tex]n=\frac{204.047atm\times 12.0L}{0.0821 L atm/K mol\times 295K}=101moles[/tex]

Thus 101 moles of oxygen are contained in the tank

Answer:

69.79

Explanation:

According to this question, Gallium element (Ga) has two isotopes namely: 69Ga and 71Ga respectively.

- Isotope 69Ga contains a percent abundance of 60.11 %, the decimal abundance= 0.6011

- Isotope 71Ga contains a percent abundance of 39.89 %, the decimal abundance = 0.3989

Atomic mass of Ga = (mass of isotope 1 × decimal abundance) + (mass of isotope 2 × decimal abundance)

Atomic mass of Ga = (0.6011 × 69) + (0.3989 × 71)

Atomic mass of Ga = 41.4759 + 28.3219

Atomic mass of Ga = 69.797

Atomic mass of Gallium = 69.79

Answer:

is always exothermic

Explanation:

You see, whether a process is endothermic or exothermic depends on the result of the operation; ΔHreaction= ΔHproducts - ΔHreactants.

If the enthalpy of reactants exceeds that of the products, then the process is exothermic.

We should remember that the energy of isolated atoms is always higher than the energy of the compound formed when the atoms bond together. Hence bond making is an exothermic process.

Energy is used to form bonds and released when they are broken, bond-breaking is considered to be endothermic. Additionally, the creation of bonds is typically an exothermic process. The formation of chemical bonds from separated atoms is exothermic. The correct option is 4.

When bonds are created in the products of exothermic processes, more energy is produced than is required to break the bonds between the reactants. The temperature of the reaction mixture rises as a result of exothermic reactions. Endothermic chemical processes are those that generally absorb (or use) energy.

An attraction between atoms or ions is referred to as a chemical bond. Atoms trade or exchange valence electrons to create bonds.

Thus the correct option is 4.

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Answer:

liquid oxygen is highly flammable

Explanation:

near any source of heat. liquid oxygen can explode to flames thus being hazardous

Answer:

136.63 °C

Explanation:

ΔTb=Tb solution - Tb pure

Where; Tb pure = 133.60°C

molar mass of solute = 121.14 g/mol

number of moles of solute; 52.2g/121.14 g/mol = 0.431 moles

molality = 0.431 moles/350 * 10^-3 = 1.23 molal

Then;

ΔTb = Kb * m * i

Kb = 2.46°C kg mol^-1

m = 1.23 molal

i = 1

ΔTb = 2.46 * 1.23 * 1

ΔTb = 3.03 °C

Hence;

Tb solution = ΔTb + Tb pure

Tb solution = 3.03 °C + 133.60°C

Tb solution = 136.63 °C

Answer:

801 g

Explanation:

From the question given above, the following data were obtained:

Number of mole of Ba₃(PO₄)₂ = 1.33 moles

Mass of Ba₃(PO₄)₂ =?

Next, we shall determine the molar mass of Ba₃(PO₄)₂. This can be obtained as follow:

Molar mass of Ba₃(PO₄)₂ = (137.3×3) + 2[31 + (4×16)]

= 411.9 + 2[31 + 64]

= 411.9 + 2[95]

= 411.9 + 190

Molar mass of Ba₃(PO₄)₂ = 601.9 g/mol

Finally, we shall determine the mass of Ba₃(PO₄)₂. This can be obtained as follow:

Number of mole of Ba₃(PO₄)₂ = 1.33 moles

Molar mass of Ba₃(PO₄)₂ = 601.9 g/mol

Mass of Ba₃(PO₄)₂ =?

Mole = mass /Molar mass

1.33 = Mass of Ba₃(PO₄)₂ / 601.9

Cross multiply

Mass of Ba₃(PO₄)₂ = 1.33 × 601.9

Mass of Ba₃(PO₄)₂ = 801 g

The question is incomplete, the complete question is;

Britney found an irregularly shaped metal object on the beach that

has a mass of 232.5 grams. To determine the volume, she partially

filled a cylindrical water bottle and dropped the object in. The

water level in the bottle rose by 1.2 cm. The bottle has a diameter

of 5 cm. Calculate the density of the metal to determine what type

of metal Britney found. Densities, measured in grams per cubic

centimeter, g

cm3

, for some common metals are listed.

• Copper: 8.86 g

cm3

• Bronze: 9.87 g

cm3

• Silver: 10.5 g

cm3

• Gold: 19.3 g

cm3

Select the word that correctly completes the sentence.

Based on the density of the metal, it is most likely that the metal Britney

found is _______________.

\ copper

\ bronze

\ silver

\ gold

Answer:

Bronze: 9.87 g

bronze

Explanation:

We know that the volume of the liquid = the volume of the object

This is because the object will cause the liquid to occupy its own volume of the container.

Now; area of the container = πr^2 = 3.142 * (5/2)^2 = 19.635 cm^2

Volume of the liquid = volume of the sold = 19.635 cm^2 * 1.2 cm= 23.562cm^3

Now given that;

Density = mass/volume = 232.5 g/23.562cm^3 = 9.87 g/cm^3

Answer: Across each row, or period, of the periodic table, the number of valence electrons in groups 1–2 and 13–18 increases by one from one element to the next. Within each column, or group, of the table, all the elements have the same number of valence electrons.

Relationship between the period number and the number of valence electrons:

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Answer:

endoskeleton i think

Explanation:

Answer:

negative

Explanation:

18 negative

19 neutral

10 positive

there are are more negative

Firework mixture is made up with potassium nitrate and other toxic chemicals. They produce harmful wastes to the atmosphere. If they are contaminated, they make release very dangerous explosives by unwanted reactions.

Explosives are chemicals releasing lot of heat energy to the surrounding upon  decomposition. Nitrogen compounds, hydrogen etc are explosive and they will explode in air or water.

Chemicals have to handled carefully and stored as per the conditions based on their chemical and physical properties. Some of them may easily corrode. Some may rapidly reacts with water or air and some may explode in air.

Explosive chemicals causes atmospheric pollution as well as health risk by releasing hazardous chemicals. If they are contaminated then there may occur some unwanted reaction and it will make the risk intense by producing toxic gases.

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Answer:

This is the idea of spontaneous generation, an obsolete theory that states that living organisms can originate from inanimate objects. Other common examples of spontaneous generation were that dust creates fleas, maggots arise from rotting meat, and bread or wheat left in a dark corner produces mice

Explanation:

hope you like my answer

1.14m x MG is the answer

Answer:

Electrons

Explanation: