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3 years ago

Osmium is one of the densest elements known, what is its density if 2.72 g has a volume of 0.121 cm3?

Chemistry

2 answers:

AnnZ [28]3 years ago

7 0

Mass / volume = density
2.72g/0.121mL = 22.5g/mL

1cm3 = 1mL

kramer3 years ago

3 0

Explanation:

The given data is as follows.

mass = 2.72 g

volume = 0.121 $cm^{3}$

As the density is mass divided by volume.

Mathematically, Density = $\frac{mass}{volume}$

Hence, putting the given values into the above formula and calculate the density as follows.

Density = $\frac{mass}{volume}$

= $\frac{2.72 g}{0.121 cm^{3}}$

= 22.47 $g/cm^{3}$

Thus, we can conclude that density of osmium is 22.47 $g/cm^{3}$ .

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Enter your answer in the provided box.

nexus9112 [7]

Answer:

V₂ = 50.93 L

Explanation:

Initial volume, $V_1=43.1\ L$

Initial temperature, $T_1=24^{\circ} C=24+273=297\ K$

Final temperature, $T_2=78^{\circ} C=78+273=351\ K$

We need to find the final volume of the gas. The relation between the volume and the temperature is given by :

$\dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}\\\\V_2=\dfrac{V_1T_2}{T_1}\\\\V_2=\dfrac{43.1\times 351}{297}\\\\V_2=50.93\ L$

So, the final volume of the gas is 50.93 L.

4 0

3 years ago

Why do water molecules and the materials dissolved in water move through the plasma membrane slowly ?

garik1379 [7]

Nonpolar and small polar molecules can pass through the cell membrane, so they diffuse across it in response to concentration gradients. Carbon dioxide and oxygen are two molecules that undergo this simple diffusion through the membrane. The simple diffusion of water is known as osmosis.

4 0

3 years ago

All of these are examples of an animal maintaining homeostasis EXCEPT:

Pie

Answer:

A whale bleeding from a cut.

Explanation:

Shivering in the cold, breathing hard during exercise, and sweating because it's hot are ways the body is working to maintain good functioning and to keep the body alive. Bleeding from a cut is not an example of this.

3 0

2 years ago

Glycolic acid, which is a monoprotic acid and a constituent in sugar cane, has a pKa of 3.9. A 25.0 mL solution of glycolic acid

Phoenix [80]

Answer:

pH = 8.0

Explanation:

First, we have to calculate the moles of NaOH.

$35.8 \times 10^{-3}L.\frac{0.020mol}{L} =7.2\times 10^{-4}mol$

Let's consider the balanced equation.

C₂H₄O₃ + NaOH ⇒ C₂H₃O₃Na + H₂O

The molar ratio C₂H₄O₃: NaOH: C₂H₃O₃Na is 1: 1: 1. So, when 7.2 × 10⁻⁴ moles of NaOH react completely with 7.2 × 10⁻⁴ moles of C₂H₄O₃ they form 7.2 × 10⁻⁴ moles of C₂H₃O₃Na.

The concentration of C₂H₃O₃Na is:

$\frac{7.2\times 10^{-4}mol}{60.8 \times 10^{-3}L} =0.012M$

C₂H₃O₃Na dissociates according to the following equation:

C₂H₃O₃Na(aq) ⇒ C₂H₃O₃⁻(aq) + Na⁺(aq)

C₂H₃O₃⁻ comes from a weak acid so it undergoes basic hydrolisis.

C₂H₃O₃⁻ + H₂O ⇄ C₂H₄O₃ + OH⁻

If we know that pKa for C₂H₄O₃ is 3.9, we can calculate pKb for C₂H₃O₃⁻ using the following expression:

pKa + pKb = 14

pKb = 14 -3.9 = 10.1

10.1 = -log Kb

Kb = 7.9 × 10⁻¹¹

We can calculate [OH⁻] using the following expression:

[OH⁻] = √(Kb.Cb) <em>where Cb is the initial concentration of the base</em>

[OH⁻] = √(7.9 × 10⁻¹¹ × 0.012M) = 9.7 × 10⁻⁷ M

Now, we can calculate pOH and pH.

pOH = -log [OH⁻] = -log (9.7 × 10⁻⁷) = 6.0

pH + pOH = 14

pH = 14 - pOH = 14 - 6.0 = 8.0

7 0

2 years ago

An ionic bond can be formed when one or more electrons are 1) equally shared by two atoms 2) unequally shared by two atoms 3) tr

Lyrx [107]

Answer:

4) transferred from the valence shell of one atom to the valence shell of another atom

Explanation:

Electrons are located outside of the nucleus which contains the protons and the neutrons.

For bonds to form, valence electrons located in the outermost shell electrons are involved. These are the valence electrons. These outer shell electrons can be shared or transferred between two combining atoms to form stable atoms.

In ionic bonds, the electrons are transferred from one specie to another. The atom that loses the electrons becomes positively charged and the receiving atom becomes negatively charged. This is the crux of ionic bonds.

6 0

2 years ago