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3 years ago

How many copper atoms are in 70g of copper

Chemistry

1 answer:

Elanso [62]3 years ago

4 0

Answer:

$n = 6.634\times 10^{23}\,atoms$

Explanation:

The total amount of atoms is found by multiplying Avogradro's Number and the number of moles:

$n = \left(6.022\times 10^{23}\,\frac{atoms}{mol} \right)\cdot \left(\frac{70\,g}{63.546\,\frac{g}{mol} } \right)$

$n = 6.634\times 10^{23}\,atoms$

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galben [10]

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3 years ago

What is the classification of a solution of naoh with a ph of 8.3?

Maksim231197 [3]

Answer:

<u>Alkaline or basic solution </u>(alkaline and basic means the same)

Explanation:

According to the <em>pH</em>, solutions may be classified as neutral, acidic, or alkaline (basic).

This table shows such classification:

pH classification

7 neutral

> 7 alkaline or basic

< 7 acidic

Thus, since the pH of the solution is 8.3, which is greater than 7, the solution is classified as basic (alkaline).

Additionally, you must learn that pH is a logarithmic scale for the concentration of hydronium ions in the solution.

pH = - log [H₃O⁺]

You can calculate the concentration of hydronium ions using antilogarithm properties:

$pH=-log[H_3O^+]\\ \\ {[H_3O^+]}=10^{-pH}\\ \\ {[H_3O^+]}=10^{-8.3}=0.00000000501$

NaOH solutions are alkaline solutions, bases, according to Arrhenius model, because they contain OH⁻ ions and release them when ionize in water.

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3 years ago

The molar madd of Ca(OH)2

Nonamiya [84]

What you have to do is find a periodic table and add the mass of each atom that the compound is made of.

Ca= 40.1
O= 16.0
H= 1.01

keep in mind that you have to also account for how many atoms of each there are in the molecule. for example, in Ca(OH)2, there are one Ca, two O and two H

so the molar mass of Ca(OH)2= 40.1 + (2 x 16.0) + (2 x 1.01)= 74.12 g/mol

8 0

3 years ago

Identify the compound that would have the highest osmotic pressure when dissolved in water. nacl k2so4 mgcl2 fecl3 mgso4

brilliants [131]

The compound that would have the highest osmotic pressure when dissolved in water is $FeCl_{3}$ .

So, option D is correct one.

The dissociation of one molecule of $FeCl_{3}$ gives the maximum number of ions when dissolved in water ( 4 ions ) . Osmotic pressure is a colligative property and depends upon number of solute particles present in the solution . The solution having maximum number of solute particles will have maximum number of the osmotic pressure .

All other given molecules gives less number of number of ions when dissolved in water as compare to of $FeCl_{3}$ .

To learn more about osmotic pressure

brainly.com/question/10046758

#SPJ4

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2 years ago

A student is given the question: "what is the mass of a gold bar that is 7.379 × 10–4 m3 in volume? the density of gold is 19.3

IRINA_888 [86]

<h3><em>Further Explanation</em></h3>

Density is a quantity derived from the mass and volume

density is the ratio of mass per unit volume

With the same mass, the volume of objects that have a high density will be smaller than type

The unit of density can be expressed in g / cm3 or kg / m3

Density formula:

$\large{\boxed{{\bold{\rho~=~\frac{m}{V}}}}$

ρ = density

m = mass

v = volume

A common example is the water density of 1 gr / cm3

The mass itself is often equated with weight, even though it is different. Mass is the amount of matter in the matter while weight is related to the gravitational force

<em>Known variable</em>

volume gold bar 7.379 × 10⁻⁴ m³

a density of 19.3 g/cm³

<em>Asked</em>

the mass of a gold bar

<em>Answer</em>

volume is known to be 7.379 × 10⁻⁴ m³, then we change it first to units of cm³ adjusting to units of density

7.379 × 10⁻⁴ m³ = 7.379 × 10² cm³

then:

mass = volume x density

mass = 7.379 × 10² cm³ x 19.3 g/cm³

mass = 1.424 x 10⁴ gram