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Answer:b.CaCl2

Explanation:

A compound is  a substance resulting when two or more elements  are are chemically bonded together either ionically or covalently in a fixed ratio.

From the given options we can see that the only compound there  is CaCl2 which is an ionic compound in the fixed  ratio of one calcium ion to two chloride ions.

Other options , Cu,Na and Nd are merely pure substance---Elements

Answer:they use cellular respiration to transform the glucose molecules they make into energy they can use for carrying out life's processes

Explanation:

The empirical and molecular formula : Mg₃Si₂H₂O₈ and Mg₆Si₄H₄O₁₆

Given

28.03% Mg, 21.60% Si, 1.16% H, and 49.21% O

Required

The empirical and molecular formula

Solution

Mol ratio : Mg : Si : H : O =

[tex]\tt \dfrac{28.03}{24}\div \dfrac{21.6}{28}\div \dfrac{1.16}{1}\div \dfrac{49.12}{16}\\\\1.17\div 0.771\div 1.16\div 3.07\\\\1.5\div 1\div 1.5\div 4\\\\3\div 2\div 2\div 8[/tex]

So empirical formula :

[tex]\tt Mg_3Si_2H_2O_8[/tex]

(Emprical formula)n=molecular formula

(Mg₃Si₂H₂O₈)n=520.8

(24.3+28.2+2.1+8.16)n=520.8

(258)n=520.8⇒n=2

The molecular formula : Mg₆Si₄H₄O₁₆

Answer:

l and lll

Explanation:

The longer the wire, the more resistance that there will be and heating a metal conductor makes it more difficult for electricity to flow through it.

Answer:

In matter a solid is anything that retains its shape and density when not confined.

a liquid is made up of a tiny particles of matter such as atom and it is also able to flow and take up a shape of any container.

Answer:

A and B

Explanation:

The number of protons is used to identify an element in the periodic table. Hence, if the number of protons is changed, the identity of the element is changed also.

The atom of an element is composed of electrons, protons and neutrons. The number of protons in an atom is also called its atomic number.

The atomic number is used to identify an element. This implies that changing the atomic number or number of protons of an element utterly changes the identity of the element.

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Answer:

The rock cycle

Explanation:

The three types of rocks are related and connected through the rock cycle. Rocks are not formed independently of one another, the process of their formation are interconnected.

 Igneous rocks are made from cooling and solidification of magma. These magma are derived from the melting of rocks that have been subjected to high temperature and pressure.

 When igneous rocks are formed, they can follow two path ways. They either get transformed to sedimentary rocks or metamorphic rocks.

When igneous rocks are subjected to metamorphic conditions, their mineralogy is altered to form metamorphic rocks.

If igneous rocks gets weathered and broken down by agents of denudation, they end up getting transformed into sedimentary rocks.

Answer:

13mL of CO₂ are produced

Explanation:

Based on the chemical reaction:

2CO(g) + O₂(g) → 2CO₂(g)

Where 1 mole of O₂ in excess of CO produce 2 moles of CO₂}

Thus, to solve this problem we need to convert the mass of oxygen gas to moles and, using the chemical reaction we can find the moles of CO₂ and its volume at STP:

Moles O₂ -Molar mass: 32g/mol-

55g O₂ * (1mol / 32g) = 1.72 moles O₂

Moles CO₂:

1.72 moles O₂ * (2 moles CO₂ / 1mol O₂) = 3.44 moles CO₂

Volume:

PV = nRT

V = P / nRT

Where P is pressure = 1atm at STP

n are moles = 3.44 moles of CO₂

R is gas constant = 0.082atmL/molK

T is absolute temperature = 273.15K at STP

V = 1atm / 3.44mol*0.082atmL/molK*273.15K

V = 0.0130L = 13mL of CO₂ are produced

N=n×Nav

n=N / Nav

(5.71×10^22) / (6.02×10^23)

n=0.09mol

According to the concept of Avogadro's number, there are 0.0948 moles of silver present in 5.71×10²² atoms of silver.

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

Therefore, number of moles=number of atoms/Avogadro's number

number of moles=5.71×10²²/6.023×10²³=0.0948

Thus, there are 0.0948 moles in 5.71×10²² atoms of silver.

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#SPJ2

Answer:evil dead 2013

Explanation:

this movie smack

Answer:

So I watched the purge which wasn't scary at all right but I watched the Nun and Anebeklle the conjuring and my cousin said that the Nun was the one possessing Anebelle after she was killed by the father of the girls during the purge and some other demon took over the Nuns soulless body since she had decided to possess the doll and the demon that possessed the Nun was Anabelle's previous owner and after hearing that I kept thinking about it for multiplretimes but I finally got over it 2 years ago.

xplanation:

1. The water inside a plant will not be able to come out.

2. It would kill the plants and species on Earth.

3. There would be no lakes, ocean, or water on land.

Answer:120.0mL

Explanation:

THANK YOU SO MUCH!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer:

thank you so much!!

Explanation:

:D

Answer:

Explanation:

I think b

Answer:

Fe = 4                 O=6

O  = 6                 Fe = 4

Explanation:

Fe + O2 > Fe2 O3

4Fe + 3O2 > 2Fe2 O3

Check

Fe = 4                Fe = 4

O  = 6                 O  = 6  

This is the balance equation.

Given :

The threshold frequency for metallic potassium is 5.46×1014 s⁻¹.

To Find :

The maximum kinetic energy and velocity that the emitted electron has the wave length of light shining on the potassium surface is 350 nm.

Solution :

We know, Maximum kinetic energy is given by :

[tex]K.E = \dfrac{hc}{\lambda}-h\nu_o\\\\K.E = h \times( \dfrac{3\times 10^8}{350\times 10^{-9}} -5.46\times 10^{14} )\\\\K.E = 6.626 \times 10^{-34}\times ( \dfrac{3\times 10^8}{350\times 10^{-9}} -5.46\times 10^{14} )\\\\K.E = 2.06 \times 10^{-19}\ J[/tex]

Hence, this is the required solution.

The kinetic energy of the electrons is 2.1  × 10^-19 J while the velocity of the electron is 6.78 × 10^5 m/s.

The work function of the metal is obtained as follows;

Wo = hfo

Wo = work function

h = Plank's constant

fo =  threshold frequency

Wo = 6.63 × 10^-34 Js ×  5.46 × 10^14 s-1 = 3.6 ×  × 10^-19 J

The energy of the incident photon is obtained from;

E = hc/λ

E = energy of incident photon

h = Plank's constant

c = speed of light

λ = wavelength of photon

E = 6.63 × 10^-34 Js × 3 × 10^8/350 × 10^-9

E = 5.7  × 10^-19 J

From the Einstein equation;

KE = E - Wo

KE = 5.7  × 10^-19 J -  3.6 ×  10^-19 J = 2.1  × 10^-19 J

Since;

KE = 1/2mv^2

v = √2KE/m

v = √2 × 2.1  × 10^-19 J/9.11 × 10^-31kg

v = 6.78 × 10^5 m/s

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Answer:

Mantle

Explanation:

Asthenosphere, zone of Earth's mantle lying beneath the lithosphere and believed to be much hotter and more fluid than the lithosphere. The asthenosphere extends from about 100 km (60 miles) to about 700 km (450 miles) below Earth's surface.

Answer: 23 g

the mol of Fe is 11,5/56 = 23/112 (mol)

the mol of CO is [tex]\frac{2,63.10^{24} }{6.10^{23} }= \frac{263}{60}[/tex] (mol)

we have:

Fe2O3 + 3CO => 2Fe + 3CO2

23/112    69/112     23/56

=> the mol of Fe is 23/56 mol

=> the mass of Fe is 23/56.56 = 23 (g)

Explanation:

Answer:

c. 2 NaOH(aq) + H2SO4(aq) = 2 H2O(l) + Na2SO4(aq)

Explanation:

The reaction of a strong acid as H2SO4 and a strong base as NaOH produce water, H2O, and the salt, Na2SO4:

H2SO4(aq) + NaOH(aq) → H2O(l) + Na2SO4(aq) -Unbalanced reaction-

To balance the sodium atoms:

H2SO4(aq) + 2 NaOH(aq) → H2O(l) + Na2SO4(aq)

And, to balance hydrogen:

H2SO4(aq) + 2 NaOH(aq) → 2H2O(l) + Na2SO4(aq)

Thus, right option is: