You are given 250 mL of a 12.0 M solution of KNO3. To obtain a 5.0 M, to what volume does the solution need to be diluted to?
600 ml
104.17 mL
0.24 mL
60 mL

Answer:

The solid crystals disappeared

Explanation:

When a soluble solid solute is added to water, the solid solute disappears after a little while. The disappearance of this solute indicates that the solute has been dissolved in water.

In this case, blue copper sulphate crystals are added to water, the blue crystals disappear leaving only a blue solution. The disappearance of these blue copper sulphate crystals indicates that the substance has dissolved in water.

Answer:

Explanation:

A covalent compound is a compound formed by covalent bonds. A covalent bond is formed between two atoms where electrons are shared between the two atoms. This forms a molecule.

What determines whether two elements will form a covalent compound or not is the number of valence electrons present in each of the elements.

Fluorine will form a covalent compound with phosphorous because fluorine has 5 electrons in its outermost shell. It needs 3 more to become stable.

Phosphorous also has 5 valence electrons. It needs 3 more to become stable.

What happens is that 3 atoms of FLuorine combine with one atom of Phosphorus, sharing the valence electrons between themselves. This leads to the formation of the PF3 molecule.

Both the Phosphorous and the Fluorine are now stable.

Answer: Phosphorus

Explanation: since both are non-metals they would both create a covalent bond.

Answer:

The period number on the Periodic table tells you the total number of orbits that the atom will have. In other words, the period number indicates the number of energy levels (or energy orbit) of an atom. For example, 1st period indicates that these elements possess 1 energy shell (or energy orbit).

Explanation:

Answer: i need help

Explanation:

Answer: 4.48 or 4.47

Answer:

338.38 K

Explanation:

Applying,

PV = nRT............... Equation 1

Where P = pressure, V = Volume, R = Temperature, n = number of moles, T = temperature.

Make T the subject of the equation,

T = PV/nR............. Equation 2

From the question,

Given: P = 1.95 atm, V = 12.3 L, n = 0.854 moles

Constant: R = 0.083 L.atm/K.mol

Substitute these values into equation 2

T = (1.95×12.3)/(0.854×0.083)

T = 338.38 K

Answer:

5.9 × 10² kJ

Explanation:

When carbon disulfide, CS₂, forms from its elements, heat is absorbed. The corresponding value for the standard enthalpy of formation of carbon disulfide is 117.36 kJ/mol. The thermochemical equation that represents this process is:

C(graphite) + 2 S(s, rhombic) ⇒ CS₂(g)   ΔH°f = 117.36 kJ/mol

117.36 kJ of heat are absorbed when 1 mole of CS₂ is formed. The amount of heat absorbed when 5.0 moles of CS₂ are formed is:

5.0 mol × 117.36 kJ/mol = 5.9 × 10² kJ

Answer:

(ii) 1 dye

(iii) Food coloring F is insoluble in the solvent

(iv) 'E' and 'H'

(b) Food colouring G

Explanation:

Paper chromatography principle is based on the rates of migration of chemicals across a sheet of paper which are different and it consists of a stationary phase such as the water in the paper and a mobile phase such as the solvent resulting in the partitioning of the components of the mixture across the paper

The solution components are positioned to start in one place from where they migrate and separate out on the chromatography paper

(ii) The number of components into which the food colouring 'H' separates into = 1

Therefore, the number of dyes in food colouring 'H' = 1 dye

(iii) Food coloring 'F' does not move because it is insoluble in the solvent, which is the mobile phase

(iv) The food colouring that contains the dye that is likely to be most soluble in the solvent are does for which the dyes travel furthest, which are;

Food coloring 'E' and 'H'

(b) Using a similar question solution found on 'tutor my self' website, we have;

The [tex]R_f[/tex] values are given as follows;

[tex]R_f = \dfrac{Distance \ moved \ by \ dye}{Distance \ moved \ by \ solvent}[/tex]

The distance moved by the solvent = 5 units

The distance moved by dyes in food colouring 'E' and 'H' = 4 units

The distance moved by dye in food colouring 'G' = 3.3 units

The distance moved by the second dye in food colouring 'E' = 2.7 units

By inspection, we get;

[tex]R_f[/tex] dye in food colouring 'G' = 3.3/5 = 0.66,

Therefore, the dye with [tex]R_f[/tex] value closest to 0.67 is the dye in food colouring 'G'.

Answer:

The tectonic style and viability of modern plate tectonics in the early Earth is still debated. Field observations and theoretical arguments both in favor and against the uniformitarian view of plate tectonics back until the Archean continue to accumulate. Here, we present the first numerical modeling results that address for a hotter Earth the viability of subduction, one of the main requirements for plate tectonics. A hotter mantle has mainly two effects: 1) viscosity is lower, and 2) more melt is produced, which in a plate tectonic setting will lead to a thicker oceanic crust and harzburgite layer. Although compositional buoyancy resulting from these thick crust and harzburgite might be a serious limitation for subduction initiation, our modeling results show that eclogitization significantly relaxes this limitation for a developed, ongoing subduction process. Furthermore, the lower viscosity leads to more frequent slab breakoff, and sometimes to crustal separation from the mantle lithosphere. Unlike earlier propositions, not compositional buoyancy considerations, but this lithospheric weakness could be the principle limitation to the viability of plate tectonics in a hotter Earth. These results suggest a new explanation for the absence of ultrahigh-pressure metamorphism (UHPM) and blueschists in most of the Precambrian: early slabs were not too buoyant, but too weak to provide a mechanism for UHPM and exhumation.

Explanation:

Answer:

0.113 liters

Explanation:

5.41 M / 47.71 moles = 0.113 liters

Answer:

The 2nd one is the one

Explanation:

and it isn't writen out all the way

Answer:

it's A.

Explanation:

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Answer: f = 760 Hz

Explanation:  speed = frequency · wavelength  v = fλ.

frequency f = v/ λ = 380 m/s / 0.50 m = 760 Hz