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Please help me!!! My hair has gotten a lot thinner recently and it s really worrying. I am a 20 year old female but I have a few theories as to why this happened. Firstly I have lost a lot of weight some of it was lost through quite severe calorie restriction. Second reason I haven t cut my hair in about a year and a half. My question is is this thinning reversible? I also dry my hair with a hairdryer and straighten it weekly. I also exercise frequently. My question is is this damage reversible? I m not going to hairdryer or straighten my hair anymore and I m going to start eating more iron and vitamins and zinc and a hair strengthening shampoo. Should I take a supplement too?

Hey so I'm a healthy weight for my height, I'm in and around 133 pounds and I'm 5 foot 4 but there's still fat around my stomach that I want to eradicate, not too much though. When I suck in my stomach I can sort of see my abs so my question is this, should I lose more weight to get abs or just do toning exercises? I already run 3 miles a day and eat healthily so I was wondering is that enough to tone up or should I be ding circuit training, HIT training, etc. any suggestions would be helpful!!! And when I say abs I don't mean a 2 pack but enough that my stomach is flat and you can being to see an outline, like a stomach flat enough that it would look good in a crop top!!! Sort of like a bikini model or something. So I basically want a flat toned stomach. Will I get this with running, a healthy diet and some toning exercises or should I lose more weight along with running, toning and a healthy diet.

Okay I'm 5 foot 4 and I weight 140 pounds but I want to lose ten pounds. I run for two miles every day and I'm increasing the distance, I cycle and I have a job in a department store 5 days a week where I don't sit down all day. At most i eat 1200 calories a day but usually I am around the 800-1000 mark and sometimes I go down to 400 if I'm very busy or alternately not doing a lot that day. In short, why has my weight plateaued? Am I consuming too little calories? I mainly eat fruit, vegetables and proteins with very few carbs and no fats, oils, refined sugars or diary. I basically eat no junk food!!! I also find myself very tired at the end of each day from the physical activity I have done and I do increase the amount each day to try and get fitter. Why has my weight loss stalled? I mean most nights I go to bed hungry and I never eat until I'm full.

Give the formula of the product formed when arsenic reacts with an excess of chlorine

Give the chemical formula of the precipitate formed when solutions of lithium acetate, barium chloride and ammonium phosphate are mixed together.

[If no precipitate is formed, write "None"]

A laser beam enters a symmetrical prism at right angles close to its upper edge exactly as shown in the diagram above.

The refractive index of the prism material is n = 1.4 and its angle is 30°.

Calculate the critical angle for the prism-air interface.

After passing through the prism, what angle does the beam make with the incident ray?

A 0.60m long wire of mass 3.0g lies flat on a table, parallel to the East-West direction. The Earth's magnetic field, of strength 5.3x10-5T, runs perpendicularly to this.

(1)What is the direction of the magnetic force on the wire if the current flows from East to West ?

(2)What is the direction of the magnetic force on the wire if the current flows from West to East?

(3) What is the minimum current that must flow through the wire to lift it?

In this question, you will calculate the resistivity of a piece of wire.

When a potential difference of 12 V is applied to a wire 7 m long and 0.35 mm in diameter the result is an electric current of 2.3 A .

What is the resistivity of the wire ?

Express your answer using two significant figures, in units of Ω m (Ohm metres).

A 0.1 M solution of an unknown organic acid has a pH of 2.1. What is the acid dissociation constant, ka, of the acid?

We can construct a buffer solution from a solution of a weak acid and a solution of a salt of the acid.

For an acid HA, we may combine a solution of the acid with a solution of the salt NaA for example, such that the following equilibrium is established:

HA(aq) + H2O(l) ↔ H3O+(aq) + A-(aq)

For such a buffer solution it may be shown that

pH = pka+ Log10([base]/ [acid])

where ka is the acid dissociation constant.

Ethanoic acid has a ka value of 1.76 x 10-5 at 298K.

Calculate the pH of an aqueous solution of a buffer solution formed by adding a solution of ethanoic acid to a solution of sodium ethanoate at 298K such that the concentration of ethanoate ions and H3O+ ions are found to be 0.0152 mol dm-3 and 0.0331 mol dm-3 respectively.

Lead chloride dissolves in water as described by the following equation:

PbCl2(s) --> Pb2+(aq) + 2 Cl-(aq)

At an unknown temperature, once equilibrium has been reached, the concentration of Pb2+(aq) ions in solution was found to be 0.0157 mol dm-3.

Calculate the solubility product of PbCl2 at this temperature. Hint: the concentration of Cl-(aq) ions must be twice that of the Pb2+(aq) ions

Select the CORRECT statements from the list given below:

Select one or more:

a. A catalyst is not involved in the reaction

b. A catalyst can change the reaction mechanism

c. A catalyst is chemically unchanged at the end of the reaction

d. Catalysts increase the activation energy for the reaction

e. Catalysts decrease the activation energy of the reaction

think there's more than one answer....b, c???

At 298K the rate constant for a first order reaction is found to be 0.0005 s-1. At 400K the rate constant is found to be 0.09 s-1.

Assuming that the pre-exponential or frequency factor A does not change with temperature, calculate the magnitude of the activation energy for the reaction, giving your answer in kJ mol-1

The Haber process for the formation of ammonia is described by the following equilibrium:

N2 (g) + 3H2 (g) <--> 2NH3 (g)

At a certain temperature, the equilibrium constant for the reaction, kp, is found to be 1 x 10-4atm-2.

At equilibrium the partial pressures of H2 and N2 in the mixture are 13.9 atm and 1.2 atm respectively. Calculate the partial pressure of the ammonia at equilibrium.

Would the answer be 5.99E-10??

In this question, you will calculate the change in potential energy when charges are moved in an electric field.

A uniform electric field with a magnitude of 6200 V m−1 points in the positive x direction.

Find the change in electric potential energy when a +16 μC

charge is moved 8 cm in the positive x direction.

Give your answer in Joules. Remember, 1μC = 1 × 10-6 C.

Find the change in electric potential energy when a +16 μC

charge is moved 8 cm in the positive y direction.

Express your answer in Joules.

In this question, a charged drop of water experiences a gravitational field, and an electric field to stop it falling.

A small water drop with a charge of 110 times that of the electron is prevented from falling (in a vacuum) by an electric field E = 1.5×105V m−1 .

What is the direction of E ?

Select one:

down

up

What is the mass of the drop ?

Give your answer in kg. Remember that the acceleration due to gravity, g, is 9.8m s−2 , and the charge on a single electron is −1.6×10−19C .

Select the correct statements from the list below

Select one or more:

a. Catalysts reduce the activation energy for a reaction

b. Catalysts increase the activation energy for a reaction

c. A catalyst must be in the same phase as the reactants to be efficient

d. A catalyst takes part in the reaction

A first order reaction is found to have a pre-exponential or 'frequency factor' A of 1*1012 s-1. The activation energy for the reaction is 72 kJ mol-1. Calculate the magnitude of the rate constant for the reaction at 298K.

Honeybees in flight can acquire electric charge. In this question, you will examine the effect of this charge.

Measurements show that a honeybee in active flight can acquire an electrostatic charge as great as 92 pC. 1 pC = 1 x 10-12 C.

How many electrons must be transferred to produce this charge?

Suppose two bees, each with a charge of 92 pC, are separated by a distance of 1.21 cm . Treating the bees as point charges, find the magnitude of the electrostatic force experienced by the bees.

Compare the force calculated in previous q to the weight of a 0.135919 gram bee. The acceleration due to gravity is 9.8 m s-2. Divide the force from Q 8 by your answer for the weight to see the difference in scale

Which of the following is the correct statement of the Arrhenius equation that relates the following parameters?

k, the rate constant

Ea, the molar activation energy

A, the pre-exponential or frequency factor

T, the temperature in Kelvin

R, the gas constant

Select one:

a. k = A exp[Ea / RT]

b. k = A exp[-Ea / RT]

c. k = -A exp[Ea / RT]

d. -k = A exp[-Ea / RT]