One of the methods that scientists can use to determine the toxicity of a chemical compound is to perform a dose-response analysis.

a. True
b. False

Answer:

Ununoctium

Explanation:

It's at the very end of the periodic table

Answer:

Ununoctium

Explanation:

Ununoctium is the last chemical element int the periodic table.

Answer:

Harmful toxins from crops have been found in peoples blood.

GM crops can cause allergic reactions in crops

Its dangerous to mess with nature this way when it should be a natural thing.

Explanation:

I'm in both Biology and Chemistry so I know a lot!

Answer:

The answer is 3

C2H5OH + O2 CO2 +H2O (unbalanced)

C2H5OH +3O2(g). 2CO2(g)+3H2O(balanced)

According to the balanced chemical equation, C₂H₅OH + 3 O₂[tex]\rightarrow[/tex] 2 CO₂ + 3 H₂O the coefficient of oxygen is three.

Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.

A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .

The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.

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Answer:

The height of A is 900

Explanation: Beside A, there is a number which explains what the height is so the answer is A.

Answer:

4.255 J/ K

Explanation:

Given data :

mass of Gallium = 16 gm

molar mass = 69.723 g/mol

hence no of moles = 16 / 69.723 = 0.23 moles --------- ( 1 )

Δh ( heat fusion ) = 5.59 KJ/mol

Temperature = 29.8°C = 302.8 k

Determine the entropy change of gallium

Δs ( entropy change ) =  heat fusion / temperature

 = ( 5.59 * 1000) J/mol / 302.8 = 18.46 J/k*mol

Hence entropy change of gallium

= Δs * no of Gallium moles

= 18.46 * 0.23 = 4.255 J/ k

I hope this is right haha

Answer:

equal number of ions

Explanation:

They cancel each other out that's why there is none

Answer:

the radius is half the diameter

The radius of a circle is equal to half the diameter.

Answer:

i think it's D tbh, just cus it was the scientist who did the work

Answer:

It depends on secondary sources and references of that secondary source. If it references just that primary source I would compare both of them and see the difference between them. Generally primary sources are more reliable but this situation is different.

Answer:

1.3-bromo,2-chloro,4-floro hexane

3.bromocyclo pentane

Explanation:

Water is called the "universal solvent" because it is capable of dissolving more substances than any other liquid. This is important to every living thing on earth. It means that wherever water goes, either through the air, the ground, or through our bodies, it takes along valuable chemicals, minerals, and nutrients.

Answer:

See explanation

Explanation:

Let us see what happens when each solution is mixed;

a) AlCl3(aq) + K3PO4(aq) ------> 3KCl(aq) + AlPO4(s)

A precipitate is formed here

b) RbCO3(aq) + NaCl(aq) -------> This is an impossible reaction hence no solid precipitate is formed here

c) MnCl2(aq) + Na2CO3(aq) → 2NaCl(aq) + MnCO3(s)

A precipitate is formed.

d) K2S(aq) + 2NH4Cl(aq) ------> 2KCl(aq) + (NH4)2S(aq)

No solid precipitate is formed

e) CaCl2(aq) + (NH4)2CO3(aq) → CaCO3(s) + 2NH4Cl(aq)

A solid precipitate is formed

Answer: 1. [tex]CO[/tex] is the limiting reagent and [tex]O_2[/tex] is the excess reagent.

2. 2.91 g of excess reagent

3. 4.66 g of carbon dioxide produced.

Explanation:

To calculate the moles :

[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]    

[tex]\text{Moles of} CO=\frac{2.98g}{28g/mol}=0.106moles[/tex]

[tex]\text{Moles of} O_2=\frac{4.62g}{32g/mol}=0.144moles[/tex]

[tex]O_2+2CO\rightarrow 2CO_2[/tex]  

According to stoichiometry :

2 moles of [tex]CO[/tex] require = 1 mole of [tex]O_2[/tex]

Thus 0.106 moles of [tex]CO[/tex] will require=[tex]\frac{1}{2}\times 0.106=0.053moles[/tex]  of [tex]O_2[/tex]

Thus [tex]CO[/tex] is the limiting reagent as it limits the formation of product and [tex]O_2[/tex] is the excess reagent.

Amount of excess reagent = ( 0.144-0.053) moles = 0.091 moles

Mass of excess reagent [tex]O_2=moles\times {\text {Molar mass}}=0.091moles\times 32g/mol=2.91g[/tex]

As 2 moles of [tex]CO[/tex] give = 2 moles of [tex]CO_2[/tex]

Thus 0.106 moles of [tex]CO[/tex] give =[tex]\frac{2}{2}\times 0.106=0.106moles[/tex]  of [tex]CO_2[/tex]

Mass of [tex]CO_2=moles\times {\text {Molar mass}}=0.106moles\times 44g/mol=4.66g[/tex]

Answer:

c

Explanation:

I am not sure but this is the answer I can provide now

Answer:

[tex]250 \times \frac{1}{63.5} \times \frac{2}{1} = 7.874mol \: ag[/tex]

Answer:

Cold air will push up the warm air, resulting in heavy rainfall in the region.

Answer: You have a solution of potassium chlorate containing 4 g at 65º C. How many additional grams of solute must be added to it, to make the solution saturated ? approximately 26 more grams [the solubility of potassium chlorate is ... water. The solution is allowed to cool. At what new temperature would crystals begin to.

Explanation:

Answer:

false

Explanation:

Answer:

e. Dilute a solution of commercial vinegar to prepare it for titration.

a. Perform a scout colorimetric titration of diluted vinegar with NaOH.

b. One pair performs a careful colorimetric titration of diluted vinegar with NaOH and the other pair performs a potentiometric titration of diluted vinegar with NaOH.

c. Perform a scout colorimetric titration of HCL with NaOH.

d. One pair performs a careful colorimetric titration of HCL with NaOH and the other pair performs a potentiometric titration of HCL with NaOH.

Explanation:

Titration is a process in which acid and base are introduced together to determine unknown concentration of acid or base. This is also known as neutralization reaction. The chemical process form salt and water as by products because acid molecules react with base molecules.

The experimental steps for the Acid-Base Equilibria in the correct order is e, a, b, c and d.

Titration is a process in which we determine the concentration of any unknown acid and base by titrating them with the standard known concentration of base or acid.

In potentiometric titration, in the place of indicator potential difference is used across the analyte of electrolytic solution. And in colorimetric titration, absorbance of light is measured by the solution. Process of method which is involved in the titration is:
e. Dilute a solution of commercial vinegar to prepare it for titration.

a. Perform a scout colorimetric titration of diluted vinegar with NaOH.

b. One pair performs a careful colorimetric titration of diluted vinegar with NaOH and the other pair performs a potentiometric titration of diluted vinegar with NaOH.

c. Perform a scout colorimetric titration of HCL with NaOH.

d. One pair performs a careful colorimetric titration of HCL with NaOH and the other pair performs a potentiometric titration of HCL with NaOH.

Hence correct sequence is e, a, b, c and d.

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Answer:

mook passes between the earth and sun

Answer : if you have time for learning and is in 6th grade the anwser is crocodilians

Explanation: i got it right

The given statement is correct or true.  

• The alignment of electrons in an atom is termed as the electronic configuration.  

• The electrons in an atom seem to assume the alignment, which gives the atoms the least possible energy.  

• This alignment of electrons is the most stable alignment and is known as the atom's ground-state electronic configuration.  

• In the ground state of an atom, the electron first enters the lowest energy orbital and later subsequent electrons are aligned in order of increasing energy. This is known as the Aufbau principle.  

Thus, the given statement is true or correct.

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Answer:

C: They become more dense near the Sun's surface.

Explanation:

I got it correct on EDG

I hope this helps!!!!!!!!

Can I have a brainliest

According to convection, the statement which describes how fluids change as they travel through the convection zone is  that they become more dense near the Sun's surface.

Convection works by areas of a liquid or gas heating or cooling greater than their surroundings, causing differences in temperature. These temperature differences then cause the areas to move as the hotter, less dense areas rise, and the cooler, more dense areas sink.

Often the areas of heating and cooling are fixed, and allow convective cycles or currents to become established. For example, a saucepan of water over a flame may develop convective currents as the water is heated from below, rises to the surface, and cools. Once cooled enough, the water then sinks back to the bottom of the saucepan where the cycle is repeated, and the convective overturning continues.

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Answer:

2.9 g of water are produced by 9.6 g of ammonium perchlorate

Note: The question is incomplete. The complete question is given below:

Ammonium perchlorate (NH₄ClO₄) is the solid rocket fuel used by the U.S. Space Shuttle. It reacts with itself to produce nitrogen gas (N₂) , chlorine gas (Cl₂), oxygen gas (O₂), water (H₂O) , and a great deal of energy. What mass of water is produced by the reaction of 9.6 g of ammonium perchlorate? Be sure your answer has the correct number of significant digits.

Explanation:

The reaction of ammonium perchlorate (NH₄ClO₄) to produce nitrogen gas (N₂) , chlorine gas (Cl₂), oxygen gas (O₂), water (H₂O) is shown in the balanced chemical equation given below:

2 NH₄ClO₄ →  N₂ +  Cl₂ + 2 O₂ + 4 H₂O

From the equation, 2 moles of ammonium perchlorate produces 4 moles of water, i.e. mole ratio of NH₄ClO₄ to H₂O = 2 : 4 = 1 : 2

molar mass of ammonium perchlorate, NH₄ClO₄ = (14 + 4 * 1 + 35.5 +16 * 4) = 117.5

molar mass of water,  H₂O = (2 * 1 + 16) = 18.0 g

mass of water produced = moles of ammonium perchlorate * 2 * molar mass of water

moles of perchlorate = mass / molar mass = 9.6/117.5

mass of water produced = 9.6/117.5 * 2 * 18.0 g  = 2.94 g of water

Therefore, 2.9 g of water are produced by 9.6 g of ammonium perchlorate

Answer:

5542.37 K

Explanation:

Given that,

Initial volume, V₁ = 590 mL

Initial temperature, T₁ = -55°C = -55 + 273 = 218 K

Final volume, V₂ = 15 L

We need to find the final temperature of the gas. The relation between the volume and the temperature is given by :

[tex]\dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}[/tex]

Where

T₂ is final volume of the gas

Put all the values in above relation,

[tex]T_2=\dfrac{V_2T_1}{V_1}\\\\T_2=\dfrac{15\ L\times 218\ K}{590\times 10^{-3}\ L}\\\\T_2=5542.37\ K[/tex]

So, the required temperature is equal to 5542.37 K.

Considering the definition of mass molar and Avogadro's Number, there are 3.0115×10²⁹ molecules in 1 ton of hydrogen.

First, the molar mass of hydrogen H₂, that is, the amount of mass that a substance contains in one mole, is 2 g/mole.

In this case, being 1 ton = 1,000,000 grams, the number of moles that 1 ton of hydrogen contains is calculated as:

[tex]1,000,000 gramsx\frac{1 mole}{2 grams} = 500,000 moles[/tex]

On the other hand, Avogadro's Number is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole.

Then, the number of molecules that 500,000 moles of hydrogen contains is calculated as:

[tex]500,000 molesx\frac{6.023x10^{23} molecules }{1 mole}[/tex]= 3.0115×10²⁹ molecules

Finally, there are 3.0115×10²⁹ molecules in 1 ton of hydrogen.

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Answer:

[tex]V_{solution}=6.25mL[/tex]

Explanation:

Hello there!

In this case, given the by-volume percent and the volume of isopropyl alcohol as the solute, we can compute the volume of the solution via:

[tex]\% v/v=\frac{V_{solute}}{V_{solution}} *100\%\\\\V_{solution}=\frac{V_{solute}}{\% v/v} *100\%[/tex]

Now, we plug in the given data to obtain:

[tex]V_{solution}=\frac{2.5mL}{40\%} *100\%\\\\V_{solution}=6.25mL[/tex]

Best regards!

Answer:

96%

Explanation:

To find the percent yield, we can use this equation

[tex]\frac{Actual}{Theoretical} *100[/tex]

The actual yield of aspirin is 3.0 and the theoretical is 3.14 in this case, so just plug the numbers in.

[tex]\frac{3.0}{3.14} *100\\\\ =96[/tex]

Thus the percent yield is 96%

;)