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2 years ago

What is one important discovery that the curies made

Chemistry

1 answer:

tatiyna2 years ago

6 0

The Curies discovered radium

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Listed below are blood groups of o, a, b, and ab of randomly selected blood donors (based on data from the greater new york bloo

KIM [24]

The answer to this is 22, confirmed by gradpoint

3 0

2 years ago

Read 2 more answers

1. In regards to curly hair, which of the following statements

Kamila [148]

Answer:

A and D are the answers

Explanation:

the other two don't make sense

3 0

2 years ago

Consider an element Z that has two naturally occuring isotopes with the following percent abundances: the isotope with a mass nu

rodikova [14]

Answer:

Z=22.70

Explanation:

It is given that,

An element Z that has two naturally occurring isotopes with the following percent abundances as follows :

The isotope with a mass number 22 is 65.0% abundant; the isotope with a mass number 24 is 35.0% abundant.

The average atomic mass for element Z is given by :

$Z=\dfrac{22\times 65+24\times 35}{100}\\\\Z=22.7$

So, the average atomic mass for element Z is 22.70.

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3 years ago

A student dissolved 1.805g of a monoacidic weak base in 55mL of water. Calculate the equilibrium pH for the weak monoacidic base

yawa3891 [41]

Answer:

11.39

Explanation:

Given that:

$pK_{b}=4.82$

$K_{b}=10^{-4.82}=1.5136\times 10^{-5}$

Given that:

Mass = 1.805 g

Molar mass = 82.0343 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{1.805\ g}{82.0343\ g/mol}$

$Moles= 0.022\ moles$

Given Volume = 55 mL = 0.055 L ( 1 mL = 0.001 L)

$Molarity=\frac{Moles\ of\ solute}{Volume\ of\ the\ solution}$

$Molarity=\frac{0.022}{0.055}$

Concentration = 0.4 M

Consider the ICE take for the dissociation of the base as:

B + H₂O ⇄ BH⁺ + OH⁻

At t=0 0.4 - -

At t =equilibrium (0.4-x) x x

The expression for dissociation constant is:

$K_{b}=\frac {\left [ BH^{+} \right ]\left [ {OH}^- \right ]}{[B]}$

$1.5136\times 10^{-5}=\frac {x^2}{0.4-x}$

x is very small, so (0.4 - x) ≅ 0.4

Solving for x, we get:

x = 2.4606×10⁻³ M

pOH = -log[OH⁻] = -log(2.4606×10⁻³) = 2.61

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2 years ago

non metals are generally non conductors of electricity. Graphite is non metal but is is used as electrodes in batteries.

expeople1 [14]

Graphite conduct electricity because it contains delocalize election (free election ) the election move through the graphite

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3 years ago