Explanation: There are many galaxies out in the universe and it's possible they go on indefinitely. Out of all of these, our solar system is very very tiny. As an analogy, our universe would be like an atom which are the the smallest units of matter. There are many other galaxies that we just haven't been able to discover but they are there.

3 0

3 years ago

Picric acid has been used in the leather industry and in etching copper. However, its laboratory use has been restricted because

olchik [2.2K]

Answer:

0.3023 M

Explanation:

Let Picric acid = $H_{picric}$

So, $H_{picric}$ + $H_2}O$ ⇄ $H_3}O^+$ + $Picric^-$

The ICE table can be given as:

$H_{picric}$ + $H_2}O$ ⇄ $H_3}O^+$ + $Picric^-$

Initial: 0.52 0 0

Change: - x + x + x

Equilibrium: 0.52 - x + x + x

Given that;

acid dissociation constant ( $K_a$ ) = 0.42

$K_a = \frac{[H_3O^+][Picric^-]}{H_{picric}}$

$0.42 = \frac{[x][x]}{0.52-x}}$

$0.42 = \frac{[x]^2}{0.52-x}}$

0.42(0.52-x) = x²

0.2184 - 0.42x = x²

x² + 0.42x - 0.2184 = 0 -------------------- (quadratic equation)

Using the quadratic formula;

$\frac{-b+/-\sqrt{b^2-4ac} }{2a}$ ; ( where +/- represent ± )

= $\frac{-0.42+/-\sqrt{(0.42)^2-4(1)(-0.2184)} }{2*1}$

= $\frac{-0.42+/-\sqrt {0.1764+0.8736} }{2}$

= $\frac{-0.42+\sqrt {1.0496} }{2}$ OR $\frac{-0.42-\sqrt {1.0496} }{2}$

= $\frac{-0.42+1.0245}{2}$ OR $\frac{-0.42-1.0245}{2}$

= $\frac{0.6045}{2}$ OR $-\frac{1.4445}{2}$

= 0.30225 OR - 0.72225

So, we go by the +ve integer that says:

x = 0.30225

x = [ $H_3}O^+$ ] = [ $Picric^-$ ] = 0.3023 M

∴ the value of [H3O+] for an 0.52 M solution of picric acid = 0.3023 M (to 4 decimal places).

6 0

3 years ago

How many grams of Ca(NO3)2 are needed to make 25.0 g of a 15.0% Ca(NO3)2(aq)?

yarga [219]

Answer:

3.75 g.

Explanation:

mass percent is the ratio of the mass of the solute to the mass of the solution multiplied by 100.

mass % = (mass of solute/mass of solution) x 100.

mass of calcium nitrite = ??? g,

mass of the solution = 25.0 g.

∴ mass % = (mass of solute/mass of solution) x 100

∴ mass of solute (calcium nitrite) = (mass %)(mass of solution)/100 = (15.0 %)(25.0 g)/100 = 3.75 g.

5 0

3 years ago

2-A gas sample is found to contain 39.10% carbon, 7.67% hydrogen, 26.11%

aleksandrvk [35]

The molecular formula :

C₆H₁₄O₃PF

<h3>Further explanation</h3>

Given

39.10% carbon, 7.67% hydrogen, 26.11% oxygen, 16.82% phosphorus, and 10.30% fluorine.

Required

The molecular formula

Solution

mol ratio :

C = 39.1 : 12 = 3.258

H = 7.67 : 1 = 7.67

O = 26.11 : 16 = 1.632

P = 16.82 : 31 = 0.543

F = 10.3 : 19 = 0.542

Divide by 0.542

C = 6

H : 14

O = 3

P = 1

F = 1

The empirical formula :

C₆H₁₄O₃PF

(The empirical formula)n = the molecular formula

(C₆H₁₄O₃PF)=184.1

(6.12+14.1+3.16+31+19)n=184.1

(184)n=184.1

n = 1

3 0

3 years ago