How many valence electrons do the alkaline earth metals have?
O A. 6
O B. 2
O C. 4
O D. 8

Answer:

Both have densities greater than that of water

Explanation:

The ability of objects to either float or sink in a liquid depends on their relative densities.

If an object is denser than a liquid it will completely sink in it, but if the density of the object is less than that of the liquid, it will sink until the weight of liquid displaced is equal to the weight of the object, then it will finally float in that liquid.

In the case of the stone bead and iron beads dropped into a cup of water, hey both sank to the bottom because they are denser than water.

Answer: 0.938 moles of [tex]ZnCl_2[/tex] will be produced.

Explanation:

To calculate the moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}[/tex]

moles of zinc:

[tex]\text{Number of moles}=\frac{61.0g}{65g/mol}=0.938moles[/tex]

[tex]Zn+2HCl\rightarrow ZnCl_2+H_2[/tex]

As HCl  is in excess , zinc is the limiting reagent and it limits the formation of product.

According to stoichiometry :

1 mole of Zn produce =  1 mole of [tex]ZnCl_2[/tex]

Thus moles of  Zn produce = [tex]\frac{1}{1}\times 0.938=0.938[/tex] moles of [tex]ZnCl_2[/tex]

Thus 0.938 moles of [tex]ZnCl_2[/tex] will be produced.

Answer:

Matter is any substance, if it is made up of only one kind of atom, then it is an element. Elements consists of atoms with the same weight and same number of protons in the nuclei.

Answer:

the answer is 5.1 1049 mol.

Answer:

[tex]\large \boxed{28 \, \% }[/tex]

Explanation:

magnesium  + nitrogen ⟶ Product

      13 g                5 g

Mass of product = 13 g + 5 g = 18 g

The product contains 5 g of nitrogen .

[tex]\text{Percent N} = \dfrac{\text{5 g}}{\text{18 g}} \times \, 100\% = \mathbf{28 \, \%}\\\text{The percent by mass of nitrogen is $\large \boxed{\mathbf{28 \, \% }}$}[/tex]

Answer:

when the coal is heat with presence of oxygen it's called combustion...

Answer:

The correct option is;

(B) 1 s², 2s², 2p⁶, 3s², 3p³

Explanation:

The electron configuration is the outline of the electron arrangement about a nucleus

In the systemic pattern of electron arrangement within an atom, there are, s, p, d, f orbitals

The maximum number of electrons in an s, p and d orbital = 2, 6, and 10 respectively

Based on Aufbau's principle the electrons are arranged based on the order of their energy level

The charge is presented by the number of electrons in the outermost shell, an element able to form an ion of charge of -3 will gain 3 electrons to complete its outermost shell

Among the options given, option B is the only option that has the capacity to take the electrons to complete the number of electrons in the p orbital outermost shell to 6 from 3, that is 3p³ + 3e⁻→ 3p⁶.

Answer:

Molarity = 2.0833 M (Approx)

Explanation:

Given:

Number of moles (n) = 0.25

Volume of solution = 120 ml = 0.12 L

Find:

Molarity

Computation:

Molarity = Number of moles (n) / Volume of solution.

Molarity = 0.25 / 0.12

Molarity = 2.0833 M (Approx)

Answer:

22

Explanation:

22

Answer:

About 2 liters

Explanation:

Since 1 gallon equals 3.785 liters, you figure out how many liters per week she uses by 3.785 x 0.75 which is 2.83875. Then divide that by 7 which is 0.405535 liters per day. Then multiply that by 5 days which is 2.027 liters in 5 days.

Answer:

The given hydrocarbon is Butanol

Answer:

100mL of chloromethane

Explanation:

Based on the equation:

Cl₂(g) + CH₄(g) → HCl(g) + CH₃Cl(g)

1 mole of chlorine reacts per mole of methane to produce 1 mole of HCl and 1 mole of chloromethane

Avogadro's law says that equal volumes of all gases, at the same temperature and pressure, have the same number of molecules. Using Avogadro's law we can say of the equation that:

1 mL of chlorine reacts per mL of methane to produce 1 mL of HCl and 1 mL of chloromethane

Because the system stays under constant pressure and temperature.

As 100mL of Cl₂ reacts with excess of CH₄ and 1mL of Cl₂ produce 1mL of CH₃Cl there are produced:

Answer:

Explanation:

GIven that:

The activation energy = 250 kJ

k₁ = 0.380 /M

k₂ = ???

Initial temperature [tex]T_1 =[/tex] 1001 K

Final temperature [tex]T_2 =[/tex] 298 K

Applying the equation of Arrhenius theory.

[tex]In \dfrac{k_2}{k_1 }= \dfrac{Ea}{R}( \dfrac{1}{T_1 }- \dfrac{1}{T_2})[/tex]

where ;

R gas constant = 8.314  J/K/mol

[tex]In \dfrac{k_2}{0.380 }= \dfrac{250 * 10^3}{8,314}( \dfrac{1}{1001 }- \dfrac{1}{298})[/tex]

[tex]In \dfrac{k_2}{0.380 }= -70.8655[/tex]

[tex]\dfrac{k_2}{0.380 }= e^{-70.8655}[/tex]

[tex]\dfrac{k_2}{0.380 }= 1.67303256 \times 10^{-31}[/tex]

[tex]{k_2}= 1.67303256 \times 10^{-31} \times {0.380 }[/tex]

[tex]{k_2}= 6.3575 \times 10^{-32}[/tex]  /M .sec

Half life:

At 1001 K.

[tex]t_{1/2} = \dfrac{In_2}{k_1}[/tex]

[tex]t_{1/2} = \dfrac{0.693}{0.38}[/tex]

[tex]t_{1/2} =[/tex] 1.82368 secc

At 298 K:

[tex]t_{1/2} = \dfrac{0.693}{6.3575 \times 10^{-32}}[/tex]

[tex]t_{1/2} =1.09 \times 10^{31} \ sec[/tex]

Answer:

ingredient. U.s unit. SI unit. SI unit(540)

flour. 2cups. ²/6. 180cups = 1.8×10²

milk. 2cups. ²/6. 180cups. =1.8×10²

eggs. 2. ²/6. 180eggs. =1.8×10²

melted butter. ⅓cup ¹/18. 30cups. =3×10¹

sugar. 1spoon. ¹/6. 90spoons. =9×10¹

baking powder 2spoons ²/6. 180spoons. =1.8×10²

salt. ½spoon. ¹/12. 45spoons. =4.5×10¹

Explanation:

1) to get the SI unit divide the U.S unit by 6

example:eggs = 2÷6. =²/6

2) to get the SI unit for 540 people ,multiply the SI unit by 540.

example:eggs ²/6×540. = 180

3)convert the answers to scientific notation

example:eggs =180. =1.8×10²

Answer:

it's a chemical Element

Explanation:

symbol He

atomic number 2.

Answer:

1) 0.1077 moles

2) 137043.2 moles

3) 180.186 grams

4) 6.53×10²² molecules or formula units

5) 1.505×10²³ ions

6) 90.626 grams

7) 0.555 moles

Explanation:

1) The number of moles, n = Mass of the substance/(Molar mass of the substance)

The molar weight of PO₄⁻³ is 94.971 g/mol

The number of moles in 10.23 g of PO₄⁻³ is n =10.23/94.971 = 0.1077 moles

The number of moles in 10.23 g of PO₄⁻³ = 0.1077 moles

2) The number of molecules of Na₂CO₃ in one mole of Na₂CO₃ is given by the Avogadro's number, [tex]N_A[/tex] = 6.02 × 10²³ molecules

Therefore, the number of moles in 8.25 × 10²⁸ molecules of Na₂CO₃ is found by determining how many Avogadro's number of molecules are in 8.25 × 10²⁸ molecules of Na₂CO₃ as follows;

The number of moles in 8.25 × 10²⁸ molecules of Na₂CO₃ = (8.25 × 10²⁸)/(6.02 × 10²³) = 137043.2 moles

The number of moles in 8.25 × 10²⁸ molecules of Na₂CO₃ = 137043.2 moles

3) The molar mass of CH₂O = 30.031 g/mol

Therefore, the mass of 6 of CH₂O = 6 moles × 30.031 g/mol = 180.186 grams

The mass of 6 of CH₂O = 180.186 grams

4) The molar mass of NaCl = 58.44 g/mol

The number of moles of NaCl in 6.34 g of NaCl 6.34/58.44 = 0.1085 moles

1 formula unit of NaCl = 1 molecule of NaCl

The number of molecules in one mole of  a substance =  [tex]N_A[/tex] = 6.02 × 10²³

Therefore, the number of molecules in  0.1085 moles of NaCl = 6.02 × 10^(23) × 0.1085 = 6.53×10²² molecules or formula units

5) The number of ions per mole of any substance is give by Avogadro's number, [tex]N_A[/tex] = 6.02 × 10²³ ions,

The number of ions in 0.25 moles of Cu⁺² = 0.25×6.02 × 10²³ ions = 1.505×10²³ ions

The number of ions in 0.25 moles of Cu⁺² =  1.505×10²³ ions

6) The molar mass of CH₄ = 16.04 g/mol

The number of moles, n, in 3.4×10²⁴ = 3.4×10^(24)/(6.02×10^(23)) = 5.65 moles 5.65*16.04

The mass of 5.65 moles of CH₄ = 5.65 moles × 16.04 g/mol = 90.626 grams

The mass of 3.4×10²⁴ molecules of CH₄ = 90.626 grams

7) The density of water = 1 g/mL

The volume of the water 10 mL

The mass of the water = Volume × Density = 10 mL × 1 g/mL= 10 grams

The molar mass of water = 18.015 g/mol

The number of moles of water in 10 g  of water = mass/(Molar mass) = 10/18.015 = 0.555 moles.

Answer:

Its 5

Explanation:

Answer:

Thick deposits of sediments carried off of the shelf  

Explanation:

The continental rise is a thick deposit of sediments that accumulate between the continental slope and the abyssal plain

A is wrong. The area of land that drops toward the deep ocean basins is the continental slope.

B is wrong. The 75-mile shallow flat area just off coastlines is the continental shelf.

D is wrong. The surf area along coastlines is the surf zone .

Answer:

B. distance light travels in a year

got it on edge :)

The statement which accurately and best describes a light-year is the total distance which light travels in a complete year

Velocity of light can simply be defined as that fundamental constant that represents the speed of electromagnetic radiation in a vacuum.

The velocity of light = 2.9979 × 10^10cm/s

So therefore, the statement which accurately and best describes a light-year is the distance which light travels in a complete year

Learn more about light-year:

https://brainly.com/question/1224192

#SPJ2

Answer:

Protons, Electrons, Neutrons

Explanation:

Neutron: 0 or Neutral

Electron: -1 or Negative

Proton: +1 or Positive

For proton and neutron look at neutr for neutral and p for positive

Answer:

❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️

The answer is Protons, Electrons, Neutrons

There is three of them.....

Hope this will help you

❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️

Explanation:

Answer:

Explanation:

The graph shows the phase diagram of water . From it , it is clear that at 100°C water remains in equilibrium with water vapour and at this temperature , the vapour pressure is equal to one  atm . So this must be boiling point of water.

At 0.7 atm pressure , boiling point must have been reduced . So when water is at 100°C , it must have been completely in vapour phase .

Now the pressure is increased to 1.4 atm . In this process of increase of pressure , the water in vapour state must have turned into liquid state as soon as the pressure increases beyond  1 atm . Beyond it its boiling point would have increased above  100°C so it can not remain in gaseous phase . At 1.4 atm , its boiling point would have increased to 110°C or so . Hence it must be in liquid phase because its temperature is below its boiling point at that pressure .

Hence water changes from gaseous phase to liquid phase when pressure changes from 0.7atm to 1.4 atm .

Answer:

4

Explanation:

none of them

they are compounds and mixtures

Answer:

4. none of them

Explanation:

Water is a compound.

Air is a mixture.

Soil is a mixture.

None of them are elements.

Answer:

B) They will react because X and Y can share two pairs of electrons to become stable

Explanation:

The electron configurations of two elements x and y are given :

X: 1s2 2s2 2p6

Y: 1s2 2s2 2p6 3s2 3p6

The statement that is true for both the elements is that, they both will react as they both can share two pairs of electrons to become stable.

To become stable the outermost shell or p orbital should have 8 electrons, so element X  can gain 2 atoms to become stable.

Element Y can also react as it can also share two atoms to fulfill its 3p orbital and will stable.

Hence, the correct option is "B".

Answer:

1. A compound is a group of elements that cannot be separated by physical methods.

NaCl is a compound becuse it cannot be separated by physical methods.

It consists of postive and negative ions.

It can be separated only by chemical reactions.

2. (a) A is a mixture of iron and sulphur and it is in liq form.

(b) Gas B is hydrogen gas and it has sharp pungent irritating smell.

(c) It is a physical change.

Explanation:

Answer:

B

Explanation:

The main aim of lab rules is to minimize the no of accidents

Answer:

The energy needed to split an atom into separate protons, neutrons, and electrons

Explanation:

The equation E = MC^2 is developed by Einstein’s Special Relativity Theory

where,

E = Energy

M = mass

C = speed of the light

The energy should be measured in Joules i.e J

The mass should be measured in Kilogram i.e Kg

And, the speed of the light should be measured in meters per second i.e ms-1

The C should be squared

Now the energy is required to divided into three particles i.e protons, electrons and neutrons

It also needs to allocate the nucleus into distinct protons and neutrons that we called binding energy of nuclear

And if the energy is required to take off an electron from an atom we called the energy of ionization

And if the energy is required to add an electron to an atom so we called it affinity of electron

Answer:

The answer is "choice 2".

Explanation:

Its glycosidic fruit juice facility would be a chromosomal hydrogen bond and an aldehyde (or acetone) team generated from the intramolecular creation of the acetals (or ketal).

Its two heterocycles created at the anomeric core from of the 2 potential stereochemical are named anomers, that's why choice "has a downward projection (from terminal CH2OH party on the opposite side)" is correct.

Answer:

The correct answer is - the second law of thermodynamics.

Explanation:

The second law of thermodynamics says that the in all heat energy exchange or transfer, and if there is no gain or lose of energy in a system, the potential energy of the particular state in that system will less than that of initial state of the system in any case.

It also suggests that the processes deals with the conversion of the heat energy are irreversible and the energy can be transfer from lower temperature system to higher temperate system without adding energy.

Thus, The fact that a heat pump requires energy to move heat from a colder object to a hotter object is a real life example of the second law of thermodynamics.

The question is incomplete, the complete question is;

To make a table of the elements, dimitri Mendeleev sorted the elements according to their?

Answer:

Atomic weights

Explanation:

Dimitri Medeleeve is a Russian scientist who worked assiduously on the project of developing a system of classifying all the elements. His periodic table was filled with spaces as many atoms weren't yet discovered. 'Eka' prefix was used to name some elements whose properties closely resembled that of their predecessors in Mendeleev's system of classification.

The dependence of the atomic properties on the weight of the atom was the basis for Mendeleeves' original classification. According to Medeleeve, elements having similar chemical properties are also expected to have similar atomic weights and their atomic weights was found to increase regularly.

The Mendeleeve concept of periodic arrangement of elements is the closest precursor of the modern periodic table as it is used in chemistry. Mendeleev arranged the elements in order of increasing relative atomic mass .

Answer:

Basic

Explanation:

The pH scale is a scale that tells us about the concentration of hydrogen ions in a solution.

Acids have many hydrogen ions. Acids have a pH of less than 7.

Bases have fewer hydrogen ions and more hydroxide ions.  Bases have a pH of less than 14.

If the solution has a pH of exactly 7, then it is pure water. Water has the same concentration of hydrogen and hydroxide ions.

The antacid tablet has a pH of roughly 9.5 Since this is less than 14, but not equal to or less than 7, this must be an base. Therefore, it is considered to be in the basic range.

Answer:

9.5 is a base

Explanation:

A ph of less than 7 is an acid

7 is neutral

7 to 14 is a base

9.5 is a base