Based on information from the periodic table, which statement is true for the
element cobalt?

Answer:

4

Explanation:

If I remember correctly, the atomic # will always be the same as the # of electrons

Answer: f = 760 Hz

Explanation:  speed = frequency · wavelength  v = fλ.

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

Answer:

The cation is written first in the name; the anion is written second in the name. Rule 2. When the formula unit contains two or more of the same polyatomic ion, that ion is written in parentheses with the subscript written outside the parentheses.

When writing the formula of a compound that contains polyatomic ion, the metal is written first followed by the central atom in the ion and then other atoms that surround the central atom.

A poly atomic ion refers to an ion that comprises of more than one atom. Such ions are common in chemistry. Examples of polyatomic ions include; PO4^3-, BH4^- etc.

When writing the formula of a compound that contains a polyatomic ion, the metal is written first then the central atom in the ion follows before other atoms that surround the central atom in the ion.

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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: i need help

Explanation:

Answer:

Explanation:

I can’t explain but this is the answer LOL

Explanation:

4.5×6.022×10²³

27.099×10²³

According to Avogadro's number, there are 27.10×10²³ atoms in  4.5 moles of Al.

Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.

It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .

According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.

Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number.As 1 mole =6.023×10²³ atoms , thus,4.5 moles =4.5×6.023×10²³ = 27.10×10²³  atoms.

Thus, there are 27.10×10²³ atoms in  4.5 moles of Al.

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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:

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:

See explanation.

Explanation:

Hello there!

In this case, according to the described chemical reaction, we first write the corresponding equation to obtain:

[tex]Cu+2AgNO_3\rightarrow 2Ag+Cu(NO_3)_2[/tex]

Thus, we proceed as follows:

Part 1 of 3: here, since the molar mass of silver and copper (II) nitrate are 107.87 and 187.55 g/mol respectively, and the mole ratio of the former to the latter is 2:1, we can set up the following stoichiometric expression:

[tex]m_{Cu(NO_3)_2}=1.29gAg*\frac{1molAg}{107.87gAg}*\frac{1molCu(NO_3)_2}{2molAg}*\frac{187.55gCu(NO_3)_2}{1molCu(NO_3)_2} \\\\m_{Cu(NO_3)_2}=1.12gCu(NO_3)_2[/tex]

Part 2 of 3: here, the molar mass of copper is 63.55 g/mol and the mole ratio of silver to copper is 2:1, the mass of the former that was used to start the reaction was:

[tex]m_{Cu}=1.29gAg*\frac{1molAg}{107.87gAg}*\frac{1molCu}{2molAg}*\frac{63.55gCu)_2}{1molCu} \\\\m_{Cu}=0.380gCu[/tex]

Part 3 of 3: here, the molar mass of silver nitrate is 169.87 g/mol and their mole ratio 2:2, thus, the mass of initial silver nitrate is:

[tex]m_{AgNO_3}=1.29gAg*\frac{1molAg}{107.87gAg}*\frac{2molAgNO_3}{2molAg}*\frac{169.87gAgNO_3}{1molAgNO_3} \\\\m_{AgNO_3}=2.03gAgNO_3[/tex]

Best regards!

Answer:

0.113 liters

Explanation:

5.41 M / 47.71 moles = 0.113 liters

Answer: C

Explanation: I have the same question, it’s for summit, my teacher helped me with this question :)

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:

The 2nd one is the one

Explanation:

and it isn't writen out all the way

Answer: 4.48 or 4.47

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:

Iron is limiting reactant

Explanation:

Based on the reaction:

Fe + S → FeS

1 mole of iron reacts per mole of Sulfur

To solve this question we must convert the mass of each reactant to moles using molar masses of each reactant. As the reaction is 1:1, the reactant with the lower amount of moles is limiting reactant.

Moles Fe -Molar mass: 55.845g/mol-

4.68g * (1mol / 55.845g) = 0.0838 moles

Moles S -Molar mass: 32.065g/mol-

2.88g * (1mol / 32.065g) = 0.0898 moles

As the amount of moles of Fe < Moles S,

Iron is limiting reactant

When 4.68 g of iron reacts with 2.88 g of sulfur to produce FeS, iron is the limiting reagent.

If in a chemical reaction two reactants are present and one of them is present in less quantity as compared to other, is known as limiting reagent.

Given chemical reaction is:
Fe + S → FeS

From the stoichiometry of the reaction it is clear that equal moles of both reactant is required for the formation of product, so their mole ratio is 1:1.

Now we calculate the moles by using the formula:

n = W/M, where

W = given mass

M = molar mass

Moles of 4.68g of iron = 4.68g / 55.845g/mole = 0.0838 moles

Moles of 2.88 of sulfur = 2.88g / 32.065g/mole = 0.0898 moles

Moles of iron is less as compare to the sulfur, so it is the limiting reagent.

Hence, iron is the limiting reagent.

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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:D

Explanation:i did the usa test prep

Answer:answer is D

Explanation:

Answer:

15.5 moles

Explanation:

Applying,

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

Where P = pressure, V = Volume, n = number of mole, R = molar gas constant, T = Temperature.

Make n the subject of the equation

n = PV/RT............... Equation 2

From the question,

Given: P = 0.899 atm, V = 425 L, T = 24 °C = (273+24) K = 297 K.

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

Substitute these values into equation 2

n = (0.899×425)/(297×0.083)

n = 15.5 moles

Answer:

a chemical reaction occured

Explanation:

bubbling and fizzing after adding a substance, most offten means a chemical reaction is happening

Answer: 2.5

Explanation:

density= 2.5

mass= 62.5 or 62.50

volume= 25 ( 75-50= 25)

so divide 62.5( or 62.50) by 25 which will led you to 2.5

Answer:

it's A.

Explanation:

have uh good day ma :)))))))

Answer:

600 mL

Explanation:

molarity 1 * volume 1 = molarity 2 * volume 2. So this means 12 * 250 = 3000 and divide that by 5 to get 600 mL.

Answer:

it will all fall unless these is air

Explanation:

Answer:

If you do it carefully enough, a small amount of water will pour out of the glass — that's supposed to happen. But try not to let any air bubbles get into the glass. Finally, slowly remove the hand holding the cardboard in place.