1. On a train ride cross-country, the trees, buildings, and people appear to be speeding by the window. This is because the train is our _____

2. Scientists use the ______
system for making measurements.

3. Physical science studies the relationships between ____,____,
and ______.

4. If 6.6 tyrannosaurs weigh 30,000 kg, then what does one tyrannosaur weigh?

5. For most activities, the ___
makes a handy frame of reference.

The unknown solid is removed by rinsing with water while the PDB is removed by rinsing with alcohol.

Solvents are substances which dissolve other substances to form solutions or mixtures.

Water is used as a solvent for inorganic substances while organic solvents such as alcohol or kerosene are used as solvents for organic substances such as PDB.

Alcohol is added to the test tube containing PDB, which then dissolves. The tube is rinsed with more alcohol until all the PDB dissolves.

Therefore, the unknown solid is removed by rinsing with water while the PDB is removed by rinsing with alcohol.

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Answer:

Hydrogen Gas is the free element

The equilibrium constant of the reaction is represented by the symbol K. Thus, option C is the correct and accurate statement about the equilibrium constant.

The equilibrium constant is a representation of the concentration of the products and the reactants of the reaction that is raised to the powers through their stoichiometry coefficient.

Its value varies and changes at different temperatures and is not always less than 1. The equilibrium constant is the ratio of the coefficient of the products to reactants.

Therefore, option C. equilibrium constant is represented by K is true.

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Toxicology is the branch which studies about toxic chemicals and their effects.

Toxicology is the branch in science in which the researches and study are done for finding the effect of the toxic  or poisonous elements on plants , animals , human and earth at large.

High levels of lead exposure is dangerous to humans as it can cause permanent disabilities , it is carcinogenic and hence can lead to death.

This is studied in toxicology.

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Answer:

A thermochemical equation for the combustion of propane (C3H8)(C3H8) is written as follows:

C3H8(l)+5O2(g)→3CO2(g)+4H2O(g);ΔH∘rxnC3H8(l)+5O2(g)→3CO2(g)+4H2O(g);ΔHrxn∘ = -2202.0 kJ/mol

The value given for ΔH∘rxnΔHrxn∘ means that:

a. the reaction of one mole of propane absorbs 2202 kJ of energy from the surroundings.

b. the reaction is endothermic.

c. the enthalpy of formation of propane is 2202 kJ/mol.

d. the reaction of one mole of propane releases 2202 kJ of energy to the surroundings.

e. None of these.

Answer:

6

Explanation:

The atomic number for phosphorous is 15, meaning that it has 15 electrons (and protons). The first and second shells would be filled up with 2 and 8 electrons respectively, leaving 5 which goes on the third shell, which is also the valence shell, meaning phosphorous has 5 valence electrons.

Since the atomic number of sulfur is 16, the first and second shells are also filled up with 2 and 8 electrons respectively, leaving 6 to be on the third shell, the valence shell. Hence, sulfur has 6 valence electrons.

A phenotypic characteristic and/or trait of the cats that exhibit variation is the fur color.

Phenotypic variation is any type of distinguishable value for a trait that depends on genetic and/or environmental factors.

Cats exhibit different fur colors depending on specific gene variants (alleles) that are inherited from their parents.

In conclusion, a phenotypic characteristic or trait of the cats that show a variation is the fur color.

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In general, the formation of a chemical bond lowers the potential energy of a chemical system, leading to a more stable arrangement.

Stored energy depends upon the relative position of various parts of a system.

In bond formation, atoms lose their potential energy to attain stability and heat is evolved. The bond formation is an exothermic reaction.

Atoms bond together to form compounds to attain lower energies than they possess as individual atoms.

A quantity of energy is equal to the difference between the energies of the bonded atoms and the energies of the broken atoms.

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Answer: a branch of chemistry concerned with the rate of chemical reactions, the factors that influence these rates, and the use of rate studies to clarify reaction mechanisms

The titration would require the same amount of NaOH.

The number of moles of solute in a solution remains the same irrespective of the amount of water added to dilute the solution.

This is in accordance with the dilution law which says that the number of moles of a solution before dilution is the same as after dilution.

Thus, the amount of NaOH needed to neutralize the vinegar will remain the same for a complete reaction since the number of moles of solute in the vinegar has not changed.

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Americium is a radioactive element .

The nuclear reaction.is given by

[tex]\rm {}^{241}_{95}Am\longrightarrow {}^{237}_{93}Np+{}^4_2\alpha[/tex]

Here alpha can be written as He too

Answer: 0.37 M

Explanation:

[tex]M_{A}V_{A}=M_{B}V_{B}\\(20.4)(0.650)=M_{B}(36)\\M_{B}=\frac{(20.4)(0.650)}{36}=\boxed{0.37 \text{ M}}[/tex]

Answer:

[tex]\huge\bold\color{pink}{- Magdonal -}[/tex]

[tex]\huge\red{\overline{\qquad\qquad\qquad\qquad}}[/tex]

[tex]\pink{\rule{1pt}{999999pt}}[/tex]

Answer:

.025 moles

Explanation:

Be Cl2   is beryllium chloride

Be = 9.0121 gm/mole

Cl = 35.45 gm mole

   Be Cl2 = 79.91 gm/mole

2 gm / 79.91 gm/mole = .025 moles

Answer:

I think yes

Explanation:

sorry i havent done these type a questions in a while

[tex]O^{2-}[/tex] is the Lewis base in the following reaction:

[tex]SO_3(g) + O^{2-}(aq)[/tex]   →  [tex]SO_4^{2-}(aq)[/tex]

Lewis base is a species that donates an electron pair.

In the above-given chemical equation, the [tex]O^{2-}[/tex]is the lewis base which is donating an electron pair to the central atom of [tex]SO_3[/tex] to form [tex]SO_4^{-2}[/tex].

Hence, [tex]O^{2-}[/tex] is the Lewis base in the following reaction:

[tex]SO_3(g) + O^{2-}(aq)[/tex]   →  [tex]SO_4^{2-}(aq)[/tex]

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We can see from the details below that, the value of the solution's molality is 1.14 mol/Kg.

The term solubility has to do with the quantity of solute that is able to dissolve in a given quantity of solvent. We have the solubility of the sodium hydrogen carbonate in water at 20 degrees as 9.6 g/100 g h2o.

Number of moles of sodium hydrogen carbonate = 9.6 g/84 g/mol = 0.114 moles

Number of moles water = 100 g /18 g/mol = 5.55 moles

Mole fraction of sodium hydrogen carbonate is obtainable by the use of the relation;

0.114 moles/0.114 moles + 5.55 moles

= 0.02

Molality of the solution = 0.114 moles/0.1 Kg = 1.14 mol/Kg

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Answer:
857.2947

Explanation:

You start with what you’re given 82g of H20 and multiply by 1 mole and the actual grams of h20 which is 18.0 then you do the mole. 1 mol of O2 and 2 mol of H2O times 6.02 x 10^23

Answer: 558.5545 g

Explanation:

The formula for a sulphate ion is [tex]\text{SO}_{4}^{\text{ }2-}[/tex], so the formula for copper sulphate is [tex]\text{CuSO}_{4}[/tex].

This means the formula mass of copper sulphate is:

So, in 3.5 moles, the mass is (159.587)(3.5)=558.5545 g

The energy of the photon from the calculation performed is 3.5 * 10^-16 J.

A photon is a packet of light. It was derived from the theory of Albert Einstein. The energy of a photon is obtained from; E = hc/λ

Now we have that;

E = 6.6 * 10^-34 * 3 * 10^8/562 * 10^-9

E = 3.5 * 10^-16 J

Missing parts:

Calculate the energy, in joules, of a photon of green light having a wavelength of 562nm?

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The solution is the mixture of the solute into the solvent particles. In 60 mL solution, 59.8 mL of solvent is added.

Solute and solvent are the components of a solution. They react and mix together to produce a homogenous mixture. The solute is a substance that is added to the solvent.

Solvents are substances that dissolve the added solute in them to make a homogenous solution.

Given,

Volume of Solute = 0.20 mL

Volume of Solution = 60 mL

The volume of solvent is calculated as:

Volume of solvent = Volume of solution - Volume of solute

= 60- 0.20

= 59.8 mL.

Therefore, 59.8 mL of solvent is present in 60 mL of solution.

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Answer:

65 ml

Explanation:

The aluminum will not float , so it will displace a volume of fluid equal to its volume.

 13.5 gm / 2.7 gm/ml = 5 ml

the new graduated cylinder measurement will be 60 + 5 = 65 ml

The formula for an isotope of oxygen with nine neutrons, including the mass number and the atomic number is 17/8 O.

Isotope is any of two or more forms of an element where the atoms have the same number of protons, but a different number of neutrons within their nuclei.

This means that atoms of isotopes will have the same atomic number but a different mass number.

According to this question, an isotope of oxygen has 9 neutrons. If oxygen has an atomic number of 8, the formula of this particular isotope is as follows: 17/8 O.

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The purpose of cracking in the production of ethene is to convert large molecules into small molecules.

Ethene can be produced from the thermal cracking of ethane and propene.

In thermal cracking, high temperature of about 750-850°C and pressure of up to about 70 atm is used to break carbon-carbon bonds. Free radicals are formed in the process.

More about petroleum refining processes:

Petroleum refinery can be classified into two broad categories, namely the main refining processes and conversion processes. Main refining processes includes distillation, absorption and adsorption, while conversion processes involves thermal cracking, catalytic cracking and hydrocracking.

As the name implies, cracking is generally the breaking up of larger molecules into smaller, more useful molecules, such as those with 5 to 12 carbons.

To better comprehend cracking processes, we can use the analogy of dropping a ceramic mug.

When this ceramic mug is dropped, it breaks into smaller ceramic pieces. This represents smaller molecules being formed from a larger molecule. The force used to break them into smaller molecules would differ in the various types of cracking processes. For example, thermal cracking mainly uses heat while catalytic cracking mainly uses a zeolite catalyst.

Note that for these cracking processes to occur, there are other conditions involved.

Additional:

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Answer:

the molecules move more quickly and their average kinetic energy decreases :D

Explanation:

Gay-Lussac's law: [tex]\frac{V1}{T1}[/tex]=[tex]\frac{V2}{T2}[/tex]

We need to convert temperature from Celsius to Kelvin

-55 C = 218 K

30 C = 303 K

V2 = V1*T2 / T1 = 0.550 *303 / 218 = 0.764 l

Answer:

5.06 half lives

Explanation:

1/2 ^n  = .03             (.03 is 3% in decimal)

                         log both sides

n log 1/2 = log .03

n = 5.06  half lives

The chemical equation for the reaction between carbon oxide and nitrogen oxide is shown below:

[tex]CO + NO \rightarrow CO_2 + N_2[/tex]

A chemical equation is an equation which uses the symbols of elements and compounds to represent the reactions which occur between elements or compounds to form products.

The chemical symbol for carbon is C, nitrogen is N, and oxygen is O.

The equation representing the reaction between carbon oxide and nitrogen oxide is shown below:

[tex]CO + NO \rightarrow CO_2 + N_2[/tex]

Therefore, the chemical equation for the reaction between carbon oxide and nitrogen oxide represents the reaction to form carbon dioxide and nitrogen gas.

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Answer:

D.) Speciation

Explanation:

A.) is incorrect because favorable traits becoming more widespread within a population usually means that the population is becoming better suited for its environment. Therefore, unless there are external factors, starvation is not a direct result of positive adaptations.

B.) is incorrect because the population is gaining adaptations that make their survival within an environment more likely, not less likely. Again, extinction is the opposite of what occurs when this happens.

C.) is incorrect because migration typically occurs when a population is experiencing hardships within their environment. This is what causes them to move somewhere else in order to increase their survival/reproductive success. As stated previously, favorable adaptations would make the population better suited for their current environment. These changes would discourage migration.

D.) is correct because speciation occurs when a population changes so much over generations to the point in which they become another species entirely. If a population undergoes numerous positive adaptations, they will become more and more fit for their environment. This newfound fitness and these changes may be so drastic that the population becomes too different to classify them the same way they once were.

Answer:

D. speciation

Explanation:

took the test