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2 years ago

Calculate the mole fraction of cai2 in an aqueous solution prepared by dissolving 0.400 moles of cai2 in 850.0 g of water.

1 answer:

7 0

1) Formulas:

a) mole fraction of component 1, X1

X1 = number of moles of compoent 1 / total number of moles

b) Molar mass = number grams / number of moles => number of moles = number of grams / molar mass

2) Application

Number of moles of CaI2 = 0.400

Molar mass of water = 18.0 g/mol

Number of moles of water: 850.0 g / 18.0 g/mol = 47.22 mol

Total number of moles = 0.400 + 47.22 =47.62

Molar fraction of CaI2 = 0.400 / 47.62 = 0.00840

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Solution A has a pH of 10, and solution B has a pH of 1. Which statement best describes these solutions?

Free_Kalibri [48]

Answer:

Solution A is a Weak Alkali, Solution B is a strong Acid.

Explanation:

At pH 10, the colour is blue, therefore it's a weak alkali.

At pH 1, the colour is red, therefore it's a strong Acid.

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2 years ago

Consider two concentric spheres whose radii differ by t = 1 nm, the "thickness" of the interface. At what radius (in nm) of sphe

Gala2k [10]

Answer:

Radius of the interior sphere = 3.847 nm

Explanation:

The volume of the shell (Vs) is equal to the difference of the volume of the outer sphere (Vo) and the volume of the inner sphere (Vi). Then:

$V_s=V_o-V_i=V_i\\V_o=2*V_i\\$

If we express the radius of the outer sphere (ro) in function of the radius of the inner sphere (ri), we have (e being the shell thickness):

$r_o=r_i+e$

The first equation becomes

$\frac{4 \pi}{3}*r_o^{3} = 2 * \frac{4 \pi}{3}*r_i^{3} \\\\\frac{4 \pi}{3}*(r_i+e)^{3} = 2 * \frac{4 \pi}{3}*r_i^{3} \\\\(r_i+e)^{3} = 2 *r_i^{3} \\\\(r_i^{3}+3r_i^{2}e+3r_ie^{2}+e^{3})=2r_i^{3}\\\\-r_i^{3}+3r_i^{2}e+3r_ie^{2}+e^{3}=0\\\\-r_i^{3}+3r_i^{2}+3r_i+1=0$

To find ri that satisfies this equation we have to find the roots of the polynomial.

Numerically, it could be calculated that ri=3.847 nm satisfies the equation.

So if the radius of the interior sphere is 3.847 nm, the volume of the interior sphere is equal to the volume of the shell of 1nm.

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2 years ago

Question 4

nata0808 [166]

Answer:

A. She can run the same distance in a shorter amount of time.

Explanation:

Speed can be computed with the formula:

$v = \dfrac{d}{t}$

Where:

v = speed

d = distance

t = time

So if you look at the formula, distance there tells you how far an object has traveled, and the time tells us how long it took to cover that distance. As you can see, speed and time are inversely proportional. This means that as one goes up, the other goes down. So if we reduce time travelling a certain distance, the speed increases.

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3 years ago

What is the appropriate chemical formula for Iron(III) Sulfate? Sulfate is SO_4^2 Fe3SO4 O a . Fe2(SO4)3 O b. O c. Fe2SO4 O d. F

AnnyKZ [126]

Answer: The chemical formula of Iron (III) sulfate is $Fe_2(SO_4)_3$

Explanation:

Iron is the 26th element of periodic table having electronic configuration of $[Ar]3d^64s^2$ .

To form $Fe^{3+}$ ion, this element will loose 3 electrons.

Sulfate ion is a polyatomic ion having chemical formula of $SO_4^{2-}$

By criss-cross method, the oxidation state of the ions gets exchanged and they form the subscripts of the other ions. This results in the formation of a neutral compound.

So, the chemical formula for Iron (III) sulfate is $Fe_2(SO_4)_3$

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2 years ago

Decide whether a chemical reaction happens in either of the following situations. If a reaction does happen, write the chemical

romanna [79]

Answer: $3Mg(s)+2SnCl_3(aq)\rightarrow 3MgCl_2(aq)+2Sn(s)$

Explanation:

Single replacement reaction is a chemical reaction in which more reactive element displaces the less reactive element from its salt solution.

A more reactive element is one which can easily lose or gain electrons as compared to the other element.

As Magnesium is more reactive than tin, it can easily displace tin from its salt solution $(SnCl_3)$ and form magnesium chloride and tin in elemental form.

The balanced chemical equation is:

$3Mg(s)+2SnCl_3(aq)\rightarrow 3MgCl_2(aq)+2Sn(s)$

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2 years ago