the mass if an element is .007502 x 10^-26 g. find the Number of significant figures when the mass is converted to mg. (both masses values have same order of magnitude)

Answer:

i dont have much detail, but im pretty sure it would be at a boil/vaporizing phase.

Answer:

manganese has greater ionization energy than Selenium

Answer:

Bond order of O22- = 1

Bond order of O22+ = 3

Explanation:

The bond order is given by;

1/2(number of bonding - number of anti bonding electrons).

In O22- , there are ten bonding and eight anti bonding electrons giving a bond order of 1 from; 1/2 (10 - 8) = 1

Similarly, for O22+ , we have ten bonding and four antibonding electrons, hence;

1/2 (10 - 4) = 3

Answer: As altitude increases, there is less air pushing down from above, which decreases the pressure.

Explanation:

Atmospheric pressure is the result of air particles being pulled to the surface of the Earth by gravity. As they are pulled, they will exert more pressure on the Earth and this is what atmospheric pressure is.

It makes sense therefore that as we move higher into the atmosphere, the atmospheric pressure will decrease because less air particles are exerting pressure as we go further off the ground.

Another way to look at it is that there is air in the earth's atmosphere and all that air has weight that is pushing down on us. As we go higher into the atmosphere, there'll be less air pushing down on us so the weight will be less.

Answer:

A as te altitude increases

Explanation:

Answer:

Because the enthalpy change of the reaction depends on the states of matter of the substances, they must be shown for each substance in the equation.

Explanation:

The enthalpy of a substance depends on the particular state of matter in which it occurs.

Therefore, in a thermo chemical equation, all the states of matters for all the chemical species in the equation must be accurately written so that the thermo chemical equation can be meaningful.

The correct statement about thermochemical equations is  the enthalpy

change of the reaction depends on the states of matter of the substances,

they must be shown for each substance in the equation.

Enthalpy is defined as the heat change that occurs in a reaction or the sum

of the internal energy present. It is associated with change in matter and  is

dependent on the physical states of the reactants and products.

This is the reason why the physical states such as solid, liquid, gas etc have

to be shown in a thermochemical equation.

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Answer:

A particular kind of matter

Explanation:

Answer:

Living Space get food or nutrients, water, and shelter. No matter where an organism lives, it must provide what it needs to survive.

Explanation:All organisms need a place to live, and store energy to take care of itself.

Answer:

72.45 mmol K⁺ and 36.225 mmol Cr₂O₇²⁻

Explanation:

It is possible to obtain millimoles of a substantce by the multiplication of molarity times milliliters of the solution.

In the solution that is 0.0750M K₂Cr₂O₇:

K⁺ = 0.0750M * 2 = 0.150M

Cr₂O₇²⁻ = 0.0750M

The millimoles of these ions are:

Millimoles K⁺:

483mL * 0.150M = 72.45 mmol K⁺

Millimoles Cr₂O₇²⁻:

483mL * 0.075M  = 36.225 mmol Cr₂O₇²⁻

Answer:

a) the element belongs to group 2

b) see image attached

c) Magnesium

d) X3N2

Explanation:

Any ion with the formula X^2+ was derived from group 2 elements. The group two element found in period 3 is magnesium alone.

Since the nitride ion has a valency of -3 and X^2+ has a valency of +2 , then a compound formed between X^2+ and the nitride ion will have the formula X3N2.

a. The group number of the element can be determined by knowing the charge of the ion. In the ion X2+ has a charge of 2+. Since representative elements typically form ions with charges equal to their group numbers, we can conclude that the group number of the element X is 2.

b. The electron-dot symbol, also known as Lewis dot symbol, represents the valence electrons of an element. Since X is a representative element in Group 2, it has two valence electrons.

c. If X is in Period 3, it could be one of the elements from Group 2 in that period. The most likely element would be Magnesium (Mg), as it is the representative element in Group 2 of Period 3.

d. The nitride ion has a charge of 3-. To form a neutral compound, the charges of X and the nitride ion must balance out. Since X has a charge of 2+ and the nitride ion has a charge of 3-, we need two X ions to balance the charge of three nitride ions. Therefore, the formula of the compound formed from X and the nitride ion is X3N2.

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Answer:

scientists use the scientific method to collect measurable, empirical evidence in an experiment related to a hypothesis. The process of the scientific method involves making conjectures.

Explanation:

kg = Ibs/2.2046 (from internet)

kg = 295/2.2046

= 133.81 kg

Answer:

E

Explanation:

Here in this question, what we will do is to select which of the pairs that do not correlate.

A. Enthalpy and heat content

This two terms are at par with each other. By definition, the enthalpy of a system simply is the total amount of heat content it has.

B. Endothermic reaction and +H

These two terms are at par with each other. An endothermic reaction is one in which heat is absorbed from the surroundings. It has a positive value for the heat content i.e the enthalpy is positive and thus H is positive.

C. Exothermic reaction and -H

An exothermic reaction is one in which heat is released to the environment. It usually has a negative value for the enthalpy and thus the value of H is negative.

D. High energy and High Stability

These two terms are not at par. When an entity has or is of high energy, it is usually unstable. An entity at a higher energy level will not be stable until it goes to a lower level of energy.

Thus higher energy level is associated with lesser stability while lower energy levels are associated with higher stability. The lesser the energy of an entity, the higher its stability.

This makes the option our answer.

Answer:

5. A. Shape and volume

6. A. Solid to liquid

7. C. Gas

Answer:

NH3 < NF3 < BCl3

Explanation:

The vapour pressure of a substance has something to do with the nature of intermolecular forces between its molecules. If the molecules of a substance are held together by strong intermolecular forces, the substance will display a low vapour pressure at a given temperature and vice versa.

Ammonia has the lowest vapour pressure because of strong intermolecular hydrogen bonds that hold its molecules together.

The trend for increasing vapor pressure will be:

NH₃<NF₃<BCl₃

We know that,

The stronger the intermolecular forces, the lower the vapor pressure, and the higher the boiling point.

Thus to solve this question we need to look the intermolecular attractions in the given molecules.

1. In ammonia molecule, since it is polar in nature. It exhibits, dipole-dipole interactions and also there is hydrogen bonding between nitrogen and hydrogen atoms. So these interactions are strongest  thus NH₃ will have lower value of vapor pressure.

2. Forces of attractions in NF₃ is also stronger in comparison to BCl₃ but weaker than NH₃ thus in terms of vapor pressure it will come after NH₃.

3. Lastly, in BCl₃ it is a non-polar molecule; it exhibits London forces which are the weakest thus it will have the higher value of vapor pressure.

Trend for intermolecular attraction:

ion-dipole>hydrogen bonding>dipole-dipole> London forces > Van der Waals forces

Therefore,

Increasing order of vapor pressure will be:

NH₃<NF₃<BCl₃

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Answer:

pH=3.40

Explanation:

For this question, we can start with the general ionization reaction of a general acid:

[tex]HA~<->~A^-~+~H^+[/tex]

The acids can produce the hydronium ion ([tex]H^+[/tex]). If we can to calculate the pH we have to use the equation:

[tex]pH=-Log[H^+][/tex]

So, if we want to calculate the pH value we have to know the concentration of the hydronium ion. For this, we can check the percentage of ionization. If we have 0.2 % of ionization, we will have only  0.2 % of hydronium ions from the initial concentration. In other words, we can calculate the concentration of [tex]H^+[/tex], if we do the 0.2% of the initial concentration, so:

[tex]0.2~M*\frac{0.2}{100}~=~0.0004~M[/tex]

With the concentration we can calculate the pH:

[tex]pH=-Log[0.0004~M]~=~3.40[/tex]

The pH value is 3.40

I hope it helps!

Answer:

y = 35.06 %.

Explanation:

The reaction of fermentation is:

C₆H₁₂O₆  →  2C₂H₅OH + 2CO₂      (1)        

From the reaction (1) we have that 1 mol of C₆H₁₂O₆ produces 2 moles of C₂H₅OH, then the number of moles of C₂H₅OH is:

[tex]n = \frac{2 moles C_{2}H_{5}OH}{1 mol C_{6}H_{12}O_{6}}*1 mol C_{6}H_{12}O_{6} = 2 moles C_{2}H_{5}OH[/tex]

Now, we need to find the mass of C₂H₅OH:

[tex]m = n*M = 2 moles*46.07 g/mol = 92.14 g[/tex]  

Finally, the percent yield of C₂H₅OH is:

[tex] \% = \frac{32.3 g}{92.14 g}*100 = 35.06 \% [/tex]

Therefore, the percent yield of C₂H₅OH is 35.06 %.

I hope it helps you!

The percent yield of C2H5OH should be 35.06% also it have the 1.00 moles.

Since

The reaction of fermentation should be

C₆H₁₂O₆  →  2C₂H₅OH + 2CO₂      (1)        

Here  1 mol of C₆H₁₂O₆ generated 2 moles of C₂H₅OH, so the number of moles of C₂H₅OH should be

= 2 moles / 1mole * 1 mole

= 2 moles C₂H₅OH

So here the percent yield should be

= 32.3 / (2 * 4607)

= 32.3 / 92.14

= 35.06%

Hence, The percent yield of C2H5OH should be 35.06% also it have the 1.00 moles.

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Answer:

Explanation:

The density of a substance can be found by using the formula

From the question

mass of metal = 54.52 g

Volume of metal = new volume - original volume of water in the cylinder

That's

new volume = 28.85 mL

original volume of water = 23.44 mL

Volume of metal

= 28.85 - 23.44 = 5.41 mL

Next we convert the volume from mL to cm³

1 mL = 1 cm³

5.41 mL = 5.41 cm³

Substitute the values into the above formula and solve

That's

We have the final answer as

Hope this helps you

Answer:

0.01981 gallons.

Explanation:

In this problem, we need to convert 75 mL of water to gallons.

We know that, 1 gallon = 3785.41 mL

To convert 75 mL to gallons, we must use to the unitary method such that,

1 mL = (1/3785.41) gallon

So,

[tex]75\ mL=75\times \dfrac{1}{3785.41}\\\\=0.01981\ \text{gallons}[/tex]

So, there are 0.01981 gallons in 75 mL of water.

Answer:

The value is [tex]U =1.3908 *10^{11} \ kg [/tex]

Explanation:

From the question we are told that

mass of carbon dioxide produced by one gallon of gasoline is [tex]m = 9.50 \ kg[/tex]

The number of cars is [tex]N = 40 \ million = 40 *10^{6} \ cars[/tex]

The distance covered by each car is [tex]d = 7930 \ mi[/tex]

The rate is [tex]R = 23.6 \ mi/ gallon[/tex]

Generally the amount of gasoline used by one car is mathematically represented as

[tex]G = \frac{d}{R}[/tex]

=> [tex]G = \frac{7930}{23.6}[/tex]

=> [tex]G = 366 \ gallons [/tex]

Generally the amount of gasoline used by N cars is

[tex]H = N * G[/tex]

=> [tex]H = 40*10^{6} * 366[/tex]

=> [tex]H = 1.464*10^{10} \ gallons [/tex]

Generally the annual production of carbon dioxide is mathematically represented as

[tex]U = m * H[/tex]

=> [tex]U =9.50 * 1.464*10^{10}[/tex]

=> [tex]U =1.3908 *10^{11} \ kg [/tex]

Answer: Cl-35

Explanation:

Answer:

[tex]\°C=5.8x10^3\°C[/tex]

[tex]\°F=1.1x10^4\°F[/tex]

Explanation:

Hello,

In this case, for the calculation of the temperature in degree Celsius we subtract 273.15 to the given temperature in kelvins:

[tex]\°C=6100-273.15\\\\\°C=5.8x10^3\°C[/tex]

Next, by applying the following equation we compute it in degree Fahrenheit:

[tex]\°F=(5.8x10^{3}*9/5) + 32\\\\\°F=1.1x10^4\°F[/tex]

Clearly, since the initial unit has two significant figures the computed units also show two significant figures.

Regards.

Answer:

1) The overlap of the p orbitals of the carbon-carbon π bond would be lost

Explanation:

Unlike simple bonds, a double bond can not rotate, since it is not possible to twist the ends of the molecule without breaking the π bond.

In the structure of but-2-ene present in the attachment, we can see the two isomers, cis and trans. These isomers cannot be interconverted by rotation around the carbon-carbon double bond without breaking the π bond.

Answer:

Please find the detailed explanation below

Explanation:

A scientific method is a sequence of steps that is used to solve a problem. Every scientific method begins with a problem that needs to be solved.

Hence, in order to determine whether water really does take longer to boil if you are watching it, we employ the steps involved in a scientific method.

1) Ask a question/Make observation: This must initiate the process. The observation/question made here is that DOES WATER TAKE LONGER TIME TO BOIL WHEN WATCHED?

2. Formulating hypothesis; an hypothesis is a testable prediction of a possible solution to the stated problem. In this case, an hypothesis could read: IF water is watched while boiling, THEN it will take a longer time to boil. A hypothesis must be tested for it to be proved or disproved.

3. Test hypothesis: The formulated hypothesis is tested via conducting an experiment. The set up of the experiment can involve one group where water is boiled while watching it and another where water is boiled without watching. The former group is called Experimental group, while the latter group is called Control group. The time it takes for each group of water to boil will be recorded.

The independent variable (manipulated variable) will be the WATCHING, while the dependent variable (tested/responding variable) will be the TIME IT TAKES FOR WATER TO BOIL

4. Analyse the data; the data refers to the recorded time for each group of water. This will be analysed and compared.

5. Make conclusion; the conclusion depends on the result, which is the recorded time for each group of boiled water. Based on the result, the hypothesis can either be rejected or accepted. For example, if the control group boils faster than the experimental group, our hypothesis will be accepted but if otherwise, the hypothesis will be rejected.

Therefore, via the scientific method, it can be determined if it really takes longer time for water to boil while watched.

Answer:

Simply carry out the mixed melting point procedure

1 here grind the two substances mix them

2.take note of the melting point of the mixture this is P

3 also get the original product from a different source okay this is Q

4.so I the melting point of P = Q then they represent a similar compound

5. But if melting point of P is not equal to Q then one of the compounds is P is acting as an impurity so they are not the same

The compound has been similar or not has been determined with the determination of the shift in the melting point of the mixture of the two compounds.

The melting point can be defined as the temperature of the substance when it has been converted from the solid state to the liquid state.

The two substances were found to have the same melting point. The compounds have been determined whether they are similar or not by the determination of the melting point of the combined mixtures.

The compounds A and B have been mixed together, and the melting point has been determined. The similar compounds in mixing will give the same melting point. While if the compounds are different, there has been a shift in the melting point of the mixture.

Thus, the compound has been similar or not has been determined with the determination of the shift in the melting point of the mixture of the two compounds.

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Answer:

A) H2O > HCCH > NH3 > CH3CH3

Explanation:

H2O is known as a neural compound which a pH close to 7.0. This however makes it more acidic due to it having the lowest pH when compared to the others in the option.

The other options however have their acidic strength as follows: HCCH > NH3 > CH3CH3. This explains why the pattern of decreasing acidic strength is H2O > HCCH > NH3 > CH3CH3

Answer:

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