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4 years ago

Please help with science

Chemistry

1 answer:

Vlad [161]4 years ago

4 0

Answer:

I think the answers are both D but I'm not for sure

Explanation:

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Determine the molar solubility for pb3(po4)2 in pure water. ksp for pb3(po4)2 is 1.0 x 10-54.

hoa [83]

Dissociation of Pb₃(PO₄)₂ is;
Pb₃(PO₄)₂(s) ⇆ 3Pb²⁺(aq) + 2PO₄³⁻(aq)
initial - -
change -X +3X +2X
Equilibrium 3X 2X

Ksp = [Pb²⁺(aq)]³ [PO₄³⁻(aq)]²
1.0 x 10⁻⁵⁴ = (3X)³ (2X)²
1.0 x 10⁻⁵⁴ = 108X⁵
X = 6.21 x 10⁻¹² M

Hence the molar solubility of Pb₃(PO₄)₂ is 6.21 x 10⁻¹² M.

7 0

3 years ago

Nitric acid is a key industrial chemical, largely used to make fertilizers and explosives. The first step in its synthesis is th

Hunter-Best [27]

Answer:

The answer is 0.36 kg/s NO

Explanation:

the chemical reaction of NH3 to NO is as follows:

4NH3(g) + 5O2(g) ⟶4 NO(g) +6 H2O(l)

We have the following data:

O2 Volume rate = 645 L/s

P = 0.88 atm

T = 195°C + 273 = 468 K

NO molecular weight = 30.01 g/mol

we calculate the moles found in 645 L of O2:

P*V = n*R*T

n = P*V/R*T

n= (0.88 atm * 645L/s)/((0.08205 L*atm/K*mol) * 468 K) = 14.78 moles of O2

With the reaction we can calculate the number of moles of NO and with its molecular weight we will have the rate of NO:

14.78 moles/s O2 * 4 molesNO/5 molesO2 * 30.01 g NO/1 molNO x 1 kgNO/1000 gNO = 0.36 kg/s NO

8 0

4 years ago

A atom has 20 electrons, 21 neutrons, and 20 protons. What is the atomic mass of the atom?

UNO [17]

name= calcium

atomic mass= 40.078 atomic mass unit

no of protons= 20

no of electrons=20

5 0

3 years ago

calculate how much acid (acetic acid) and how much conjugate base (sodium acetate) must be used to make 500ml of a 0.8m acetate

kirza4 [7]

For the desired pH of 5.76, 0.365 mol of acetate and 0.035 mol of acid are to be added

let the concentration of acetate be x

then the concentration of acid will be (0.8 - x)

pKa of acetate buffer = 4.76

pH = pKa + log([acetate]/[acid])

⇒4.76 = 4.76 + log(x/(0.8-x))

⇒log(x/(0.8-x)) = 0

⇒x/(0.8-x) = 1

⇒x = 0.4

Therefore

[acetate] = x = 0.4

[acid] = 0.8-x =0.4 M

number of mol = concentration *(volume in mL)

number of mol of acetate = 0.4*0.5

= 0.20 mol

number of mol acid = 0.4*0.5

= 0.20 mol

when desired pH = 5.76

pH = pKa + log([acetate]/[acid])

⇒5.76 = 4.76 + log(x/(0.8-x))

⇒log(x/(0.8-x)) = 1

⇒x/(0.8-x) = 10

⇒x = 8 - 10x

⇒x = 8/11

⇒x= 0.73

[acetate] = x= 0.73

[acid] = 0.8-x = 0.07 M

number of mol = concentration * (volume in mL)

number of mol acetate to be added = 0.73*0.5 = 0.365 mol

number of mol acid to be added = 0.07*0.5 = 0.035 mol

Problem based on acetic acid required to maintain a certain pH

brainly.com/question/9240031

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4 0

1 year ago

In a Dam, If we doubled the depth of the dam the hydrostatic force will be ?

AnnZ [28]

Answer: Option (A) is the correct answer.

Explanation:

Force acting on a dam is as follows.

F = $\frac{1}{2}\rho g\omega H^{2}$ .......... (1)

Now, when we double the depth then it means H is increasing 2 times and then the above relation will be as follows.

F' = $\frac{1}{2}\rho g\omega (2)^{2}$

F' = $\frac{1}{2}\rho g\omega 4$ ........... (2)

Now, dividing equation (1) by equation (2) as follows.

$\frac{F}{F'}$ = $\frac{\frac{1}{2}\rho g\omega H^{2}}{\frac{1}{2}\rho g\omega 4}$

Cancelling the common terms we get the following.

$\frac{F}{F'}$ = $\frac{1}{4}$

4F = F'

Thus, we can conclude that if doubled the depth of the dam the hydrostatic force will be 4F.

4 0

3 years ago