Read the information about the halogen family.



Elements within a group share similar properties. Elements in the halogen family, such as fluorine (F), chlorine (Cl), bromine (Br), and iodine (I), all have seven valence electrons. Iodine is an important element for human health. The thyroid gland uses iodine to produce hormones. One of the hormones it makes is a covalent compound called thyroxine.


Given this information, what effect do you think other halogen elements have on human health? State your prediction, and do some research on one of the halogen elements to see how it affects human health. List your findings, and then give your opinion on whether you think the element you chose should be used in food products, cleaning products, or in other manners that cause it to come in contact with humans. Be sure to provide evidence from your research to support your opinion.

In a closed system, the total energy before an energy transformation is greater than the total energy after it.

A closed system is a natural physical system that does not permit the movement of matter into or out of the system, while energy transfer is permitted in some situations, such as those found in physics, chemistry, or engineering.

A closed system is one that only allows the flow of energy; it forbids the exchange of matter. The heat can transfer when we boil water with a closed cover, but the matter cannot.

In a closed system, the overall energy is constant. The universe's overall energy is always changing. Mass may be used to store energy. In a closed system, energy may be transformed from one form to another.

Thus, option D is correct.

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Answer:

-1.35 degree

Explanation:

Given the specific rotation of (S)-2-butanol = +13.5 degree

So, the specific rotation of its enantiomer (R)-2-butanol = -13.5 degree

Now the optical rotation of a pure liquid is given by

[tex]$\theta = [\alpha]_\lambda ^t.l.d$[/tex]

Here, [tex]$\theta$[/tex]  = the optical rotation

         [tex]$[\alpha]_\lambda^t$[/tex] = specific rotation at temperature 't' and wave length 'λ'

                = -13.5 degree

         l = optical path length

           = 1 dm

          d  = density

             = 1/10

Therefore,

[tex]$\theta = -13.5 \times 1 \times \frac{1}{10}$[/tex]

    = -1.35 degree

Answer:

I believe it would be ionic using the stock system.

Explanation:

The only difference is the size of cations, Cs+ being larger than Na+ and hence Na+ will have more polarising power than Cs+ and hence NaCl will be more covalent than CsCl or in other words CsCl will be more ionic than NaCl.

Answer:

See explanation and image attached

Explanation:

Starting from acetylene, we can react the substrate with methyl iodide in the presence of sodamide and ammonia. We then obtain propyne which then undergoes a similar reaction using butyl iodide to yield 2-heptyne.

This may now be reduced using hydrogen and platinum to yield heptane. Heptane is chlorinated in the presence of light to yield a mixture of products of which 1-chloroheptane is one.

Answer:

Answer. Answer: Nitrogen (N), antimony (Sb), bismuth (Bi) is the order from least conductive to most conductive.

Answer:

nitrogen (N), antimony (Sb), bismuth (Bi)

sorry but I need some three point so that's why I didn't

Answer:

A is probably ur answer

Explanation:

but if I'm wrong My bad and at least I tried

Answer:

It lights on fire

Explanation:

The friction sparks the match causing it to go on fire.

pH of buffer solution : 4.32

A buffer solution is a solution that can maintain a good pH value due to the addition of a little acid or a little base or dilution.

The buffer solution can be acidic or basic

Acid buffer solutions consist of weak acids(H₂CO₃) and their salts.(NaHCO₃)

mol H₂CO₃

[tex]\tt 0.032\times 0.25=0.008[/tex]

mol NaHCO₃

[tex]\tt 0.02\times 0.15=0.003[/tex]

[tex]\tt [H^+]=Ka\dfrac{mole~weak~acid}{mole~salt}\\\\(H^+]=1.8\times 10^{-5}\dfrac{0.008}{0.003}=4.8\times 10^{-5}\\\\pH=5-log~4.8=4.32[/tex]

Answer:

Explanation:

The size of the orbital is determined by the principal quantum number (n), so the size of the orbital increases as this value increases. Therefore, an electron in a 1 orbital is closer to the nucleus than is an electron in a 2 orbital.

An atomic orbital can be thought  of as the wave function of an electron in an atom. The Principal Quantum Number (n)  is one of the quantum numbers that are required to describe the distribution of electrons in atoms. This quantum number has positive integral values such as 1, 2, 3 and so on. It also relates to the mean distance of the electron from the nucleus in a given orbital. The larger the quantum number, the greater the mean distance of an electron in that orbital from the nucleus, therefore the orbital will be larger.

Answer:  mass = 485 grams approximately

=======================================================

Work Shown:

First we need the volume of the block

volume = (length)*(width)*(height)

volume = (4.22)*(3.62)*(1.41)

volume = 21.539724

volume = 21.5 cubic cm

I'm rounding to three sig figs because each of the dimensions are to three sig figs.

--------------------------

Now turn to the formula

density = mass/volume

This can be rearranged to

mass = density*volume

Plug in the given density and the volume we found earlier to get

mass = density*volume

mass = (22.57)*(21.5)

mass = 485.255

mass = 485 grams

I'm rounding to three sig figs because it's the smaller sig fig count of 22.57 and 21.5

Answer: D

Explanation:

On edge

Answer:

D

Explanation:

just did it on Ed

Answer:

Ionic compounds generally form between elements that are metals and elements that are nonmetals. For example, the metal calcium (Ca) and the nonmetal chlorine (Cl) form the ionic compound calcium chloride (CaCl2). In this compound, there are two negative chloride ions for each positive calcium ion.

Answer:

1. 4.93 = pKb of the weak base

2. pH = 12.61

Explanation:

1. When a weak base, B, is being titrated with HCl, the reaction occurs as follows:

B + HCl → BH⁺ + Cl⁻

That means the moles added of HCl are the moles of BH⁺ produced and moles of B are initial moles of B - Moles of HCl

Thus:

Moles B:

Initial moles:

0.0250L * (0.130mol / L) = 3.25x10⁻³ moles B

Moles HCl:

8.5x10⁻³L * (0.130mol / L) = 1.105x10⁻³ moles HCl

3.25x10⁻³ - 1.105x10⁻³ =

Moles BH⁺ = Moles HCl:

pH of the buffer made from B/BH⁺ is determined using H-H equation for weak bases:

pOH = pKb + log [BH⁺] / [B]

Where pOH is 14-pH = 14-9.36 = 4.64

pKb is pKb of the weak base, our unknown.

[BH⁺] could be taken as moles of BH⁺ =  1.105x10⁻³ moles

And [B] as moles of B = 2.145x10⁻³ moles B

Replacing:

pOH = pKb + log [BH⁺] / [B]

4.64 = pKb + log [1.105x10⁻³ moles] / [2.145x10⁻³ moles]

4.64 = pKb -0.288

2. When HCl and NaOH are in solution the reaction that occurs is:

HCl + NaOH → H₂O + NaCl

To find pH we need to determine, first, which reactant is in excess:

Moles HCl:

0.023L * (0.230mol / L) = 5.29x10⁻³ moles

Moles NaOH:

0.033L * (0.0230mol / L) = 7.59x10⁻³ moles

That means NaOH is in excess and after the reaction will remain:

7.59x10⁻³ moles - 5.29x10⁻³moles = 2.3x10⁻³ moles NaOH = Moles of OH⁻

In 23+33mL = 56mL = 0.056L:

2.3x10⁻³ moles OH⁻ / 0.056L = 0.0411M [OH-]

As pOH = -log [OH-]

pOH = 1.39

pH = 14 - pOH

Answer:

The net reaction is:

1/2 C    +    F  +               →      A   +   B       D  

The overall heat of this reaction = 40.96 kJ

Explanation:

Given that:

3A   +   6B   →   3D      ΔH = -418  kJ

E       +  2F   →    A       ΔH =  -118.2 kJ

             C    →  E  +   3D ΔH = 60.8  kJ

The first process says we should reverse the first equation and multiply it by 1/6

i.e.

3D × 1/6 →  3A × 1/6 + 6B ×  1/6   ;  ΔH  =  +1/6 × 418 kJ

1/2D →   1/2 A  + B                         ; ΔH  =  69.66 kJ

Then the second and the third equation are divided by 2

1/2 × E   + F → 1/2 A           ; ΔH  = -1/2  ×  118.2  kJ

1/2C  →   1/2 E   + 3/2  D    ; ΔH  =  1/2  ×  60.8 kJ

By adjusting the three equations together; we have:

1/2D →   1/2 A  + B             ; ΔH  =  69.66 kJ

1/2 × E   + F → 1/2 A           ; ΔH  =   -59.1  kJ

1/2C  →   1/2 E   + 3/2  D    ; ΔH  =   30.4  kJ                      

1/2C + F → A + B + D         ; ΔH  =  (69.66 - 59.1 + 30.4) kJ

                                            ΔH  =  40.96  kJ

The net reaction is:

1/2 C    +    F  +               →      A   +   B       D  

The overall heat of this reaction = 40.96 kJ

Answer:

It is 161.97324 g/mol

1 molecule

Answer:

Explanation:  check my paage

Answer:

C                  

Explanation:

Answer:

my gues is red not a 100% but its in the 700s

Explanation:

Answer:

A

Explanation:

gyx3gevedyhsdv

The branch of science which deals with chemicals and bonds is called chemistry.

The correct answer is A.

The polarity is defined as the separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end.

The polar molecule has the following:-

In, the first compound the polarity is the same because the compound is the same that is O-F and CL-F.

Hence, the correct answer is A.

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Answer:

25J

Explanation:

K.E = 1/2mv^2

= 1/2*0.5*10^2

= 25J

The kinetic energy of the ball is 25 J

Kinetic energy can be defined as the energy possessed by an object in motion. Mathematically, it can be expressed as:

KE = ½mv²

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

KE = ½mv²

KE = ½ × 0.5 × 10²

KE = 0.25 × 100

KE = 25 J

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Answer:

See explanation

Explanation:

The melting point range of a pure compound is about 1-2ºC of the expected melting point. An impure solid melts within a range   that is both larger than that of the pure substance  (>1ºC) and begin at a  lower temperature because impurities decrease the meting point. A melting range of 5º or more  indicates that a compound is impure.

Since the melting points of A and B are estimated  at 133 o C, the melting point range for each pure substance must be slightly different from each other. The melting point of the unknown is measured and its range is compared with the melting point ranges of pure A and B then decision can  now be made about the identity of the unknown solid.

Answer:

0.0099M = [F⁻]

Explanation:

For BaF2, Ksp = 1.7x10⁻⁶

When BaF₂ is in solution, the equilibrium between the solid and the dissociated ions occurs as follows:

BaF₂(s) ⇄ Ba²⁺(aq) + 2F⁻(aq)

Where Ksp = 1.7x10⁻⁶ is defined as:

1.7x10⁻⁶ = [Ba²⁺] [F⁻]²

Where [] are equilibrium concentrations of each ion in solution.

That means you will add F⁻ until its concentration exceeds:

1.7x10⁻⁶ = [0.0173] [F⁻]²

9.827x10⁻⁵ = [F⁻]²

When more F⁻ is added, BaF₂ begins its precipitation.

Answer:

Hydrogen peroxide is a highly reactive chemical containing the elements hydrogen and oxygen. Pure hydrogen peroxide is a colourless liquid, but it is sold on the market as solutions in water, containing up to 33 – 37% pure hydrogen peroxide and other additives to stop the product decomposing.

Explanation:

Hope this helps <3

Answer:

Younger/newer

Explanation:

Stratagraphic means an intrusion or fault is younger than the layer it affects.

Answer:

C. The reaction can be broken down and performed in steps

Explanation:

Hess's Law of Constant Heat Summation states that irrespective of the number of steps followed in a reaction, the total enthalpy change for the reaction is the sum of all enthalpy changes corresponding to all the steps in the overall reaction. The implication of this law is that  the change of enthalpy in a chemical reaction is independent of the pathway between the initial and final states of the system.

To obtain MgO safely without exposing magnesium to flame, the reaction sequence shown in the image attached may be carried out. Since the enthalpy of the overall reaction is independent of the pathway between the initial and final states of the system, the sum of the enthalpy of each step yields the enthalpy of formation of MgO.

Answer: Some salt is trapped between ice crystals, but most are left behind in the unfrozen seawater.

Explanation:

Answer: The salinity of the water increases

Explanation: Hope this helps!

Answer:

polar

Explanation:

because carbon and sulfur have different electronegativities, the S=C bond is polar.

The entire molecule is nonpolar however because the dipoles (polar bonds) cancel out due to the geometry of the molecule (linear)