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3 years ago

The scientific notation for 0.000043 is

Chemistry

1 answer:

dolphi86 [110]3 years ago

5 0

The scientific notation would be 4.3×10−5

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What is Mars colonization?

serious [3.7K]

Answer:The colonization of Mars has received interest from public space agencies and private corporations and has received extensive hypothetical treatment in science fiction writing, film, and art.

Explanation:

3 0

3 years ago

A chemist must prepare of 800.0 ml potassium hydroxide solution with a pH of 13.00 at 25Â°.

ArbitrLikvidat [17]

Answer:

4.48 grams is the mass of potassium hydroxide that the chemist must weigh out in the second step.

Explanation:

The pH of the solution = 13.00

pH + pOH = 14

pOH = 14 - pH = 14 - 13.00 = 1.00

$pOH=-\log[OH^-]$

$1.00=-\log[OH^-]$

$[OH^-]=10^{-1.00} M=0.100 M$

$KOH(aq)\rightarrow K^+(aq)+OH^-(aq)$

$[KOH]=[OH^-]=[K^+]=0.100 M$

Molariy of the KOH = 0.100 M

Volume of the KOH solution = 800 mL= 0.800 L

1 mL = 0.001 L

Moles of KOH = n

$Molarity=\frac{Moles}{Volume(L)}$

$0.100 M=\frac{n}{0.800 L}$

n = 0.0800 mol

Mass of 0.0800 moles of KOH :

0.0800 mol × 56 g/mol = 4.48 g

4.48 grams is the mass of potassium hydroxide that the chemist must weigh out in the second step.

4 0

3 years ago

has a standard free‑energy change of − 3.59 kJ / mol at 25 °C. What are the concentrations of A , B , and C at equilibrium if, a

Mamont248 [21]

Answer: The concentrations of A , B , and C at equilibrium are 0.1583 M, 0.2583 M, and 0.1417 M.

Explanation:

The reaction equation is as follows.

$A + B \rightarrow C$

Initial : 0.3 0.4 0

Change: -x -x x

Equilbm: (0.3 - x) (0.4 - x) x

We know that, relation between standard free energy and equilibrium constant is as follows.

$\Delta G = -RT ln K$

Putting the given values into the above formula as follows.

$\Delta G = -RT ln K$

$-3.59 kJ/mol = -8.314 \times 10^{-3} kJ/mol K ln (\frac{x}{(0.3 - x)(0.4 - x)})$

x = 0.1417

Hence, at equilibrium

[A] = 0.3 - 0.1417

= 0.1583 M

[B] = 0.4 - 0.1417

= 0.2583 M

[C] = 0.1417 M

5 0

3 years ago

a compound with the empirical formula CH2 has a molar mass of 112 g/mol. What is the molecular formula for this compound?

miv72 [106K]

Hope it cleared your doubt :-D

5 0

4 years ago

3690 J of heat are added to a 21.5 g sample

Fiesta28 [93]

Answer:

693K

Explanation:

The enthalpy change in the iron is 3690J

We now apply the formula for enthalpy change which is ΔH=mC∅ where ∅ is the temperature change, m the mass of the substance, and C the specific heat capacity for the substance.

ΔH in this case is 3690J.

Therefore 3690J=21.5g×0.449J/g.K×∅

as we are looking for ∅, we make it the subject of the formula.

∅=3690J/(21.5g×0.44J/g)

∅=390

Temperature=30°C +390

=420°+273

=693K

6 0

4 years ago