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3 years ago

15

How are the formulas for ionic and covalent compounds determined?

2 answers:

SVEN [57.7K]3 years ago

8 0

Answer:

Writing Formulas of Ionic Compounds

The cation is written first, followed by the monatomic or polyatomic anion. The subscripts in the formula must produce an electrically neutral formula unit.

olya-2409 [2.1K]3 years ago

5 0

Answer:

Pause the video to take as much time as needed. Pause it to create more wait-time to answer questions before I move on. One of the best ways to learn is to quiz yourself as you go along.

Explanation:

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What features of earth's crust do convergent divergent and transform boundaries form

12345 [234]

Plate tectonics are the broken plates of earth that move around and form the different plate boundaries

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3 years ago

(30 Points) You need to produce a buffer solution that has a pH of 5.02. You already have a solution that contains 10. mmol (mil

chubhunter [2.5K]

<span>By definition:

pH = pKa + log [acetate]/ [acetic acid]

so

5.02 = 4.74 + log [acetate] / 10 mmole

10mmole = 10/1000 = 0.01 mole

5.02 = 4.74 + log [acetate] / 0.01

5.02 - 4.74 = 0.28 = log [acetate] /0.01

10^0.28 = </span><span>1.90546</span> = [acetate] / 0.01 <span>
[acetate] = 0.019 mole

= 19 millimoles

</span>

8 0

3 years ago

Read 2 more answers

It has been suggested that the surface melting of ice plays a role in enabling speed skaters to achieve peak performance. Carry

vesna_86 [32]

Explanation:

Relation between pressure, latent heat of fusion, and change in volume is as follows.

$\frac{dP}{dT} = \frac{L}{T \times \Delta V}$

Also, $\frac{L}{T} = \Delta S^{fusion}_{m}$

where, $\Delta V^{fusion}_{m}$ is the difference in specific volumes.

Hence, $\frac{dP}{dT} = \frac{\Delta S^{fusion}_{m}}{\Delta V^{fusion}_{m}}$

As, $\Delta S^{fusion}_{m} = \frac{L}{T} = \frac{6010}{273.15}$ = 22.0 J/mol K

And, $\Delta V^{fusion}_{m} = \frac{M}{d_{H_{2}O}} - \frac{M}{d_{ice}}$ ...... (1)

where, $d_{H_{2}O}$ = density of water

$d_{ice}$ = density of ice

M = molar mass of water = $18.02 \times 10^{-3} kg$

Therefore, using formula in equation (1) we will calculate the volume of fusion as follows.

$\Delta V^{fusion}_{m} = \frac{M}{d_{H_{2}O}} - \frac{M}{d_{ice}}$

= $\frac{18.02 \times 10^{-3}}{997} - \frac{18.02 \times 10^{-3}}{920}$

= $-1.51 \times 10^{-6}$

Therefore, calculate the required pressure as follows.

$\frac{dP}{dT} = \frac{22}{-1.51 \times 10^{-6}}$

= $1.45 \times 10^{7} Pa/K$

or, = 145 bar/K

Hence, for change of 1 degree pressure the decrease is 145 bar and for 4.7 degree change dP = $145 \times 4.7 bar$

= 681.5 bar

Thus, we can conclude that pressure should be increased by 681.5 bar to cause 4.7 degree change in melting point.

5 0

3 years ago

[Ca2+] within the endoplasmic reticulum (ER) is 10-3M. Cytosolic [Ca2+] is 10-7M. Lysosomes in mammalian cells have an internal

Pani-rosa [81]

Answer:

B. Ca2+ import into the ER because it has the steeper concentration gradient

Explanation:

ΔGt = RT㏑(C₂/C₁)

where ΔGt is the free energy change for transport; R = 8.315 J/mol; T = 298 K; C₂/C₁ is ratio of concentrations inside and outside each organelle.

For Ca²⁺ import

ΔGt = 8.315 J/mol * 298 K * ㏑(10⁻³/10⁻⁷)

ΔGt= 3.42 kJ/mol

For H⁺ import

ΔGt = 8.315 J/mol * 298 K * ㏑ (10⁻⁴/10⁻⁷)

ΔGt = 2.73 kJ/mol

From the above values, ΔGt is greater for Ca²⁺ import because it has a steeper concentration gradient

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3 years ago

If an atom has a mass number of 23, which of the following is always true?

lesantik [10]

Atomic number is less than 11

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3 years ago