Science fair ideas???

Answers

Answer 1

Answer:

You can use a website called sciencebuddies to find a project

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The atomic number of an atom is alwaysequal to the number of its. (1) protons, only. (2) neutrons, only. (3) protons plus neutrons. (4) protons plus electrons

Given the balanced equation:F2 energy → F F
Which statement describes what occurs during
this reaction?
(1) Energy is absorbed as a bond is formed.
(2) Energy is absorbed as a bond is broken.
(3) Energy is released as a bond is formed.
(4) Energy is released as a bond is broken.

Answers

Answer: The correct option is 2.

Explanation: We are given in the question that Fluorine molecule is dissociating into two Fluorine atoms. Equation for the following is given by:

$F_2+energy\rightarrow F+F$

In a chemical reaction if the energy is written at the reactant side, the energy is being absorbed and if the energy is written at the product side, the energy is being released.

From the given chemical equation, the energy is written at the reactant side, so the energy is being absorbed by the reactants in order to break the bond between $F_2$ molecule to form 2 individual Fluorine atoms.

Hence, the correct option is 2.

(2) Energy is absorbed as a bond is broken is the correct answer.

At STP 10 grams of CO can be dissolved in 3 L of water. Calculate the solubility of carbon monoxide at 200kPa.

Answers

moles CO = 10 g x 1mol 28g = 0.357 moles in 3 L = 0.119 mol/L at STP
P1/n1 = P2/n2
101.325 kPa/0.119 = 200 kPa/n2
n2 = 0.235 moles/L = 0.235mol x 28g/mol = 6.6g/L (assuming no change in temp)

Answer : The solubility of carbon monoxide gas at pressure 200 kPa is, 6.579 g/L

Explanation :

According top the Henry's Law, the solubility of a gas in a liquid is directly proportional to the pressure of the gas.

$S\propto P$

or,

$(S_1)/(S_2)=(P_1)/(P_2)$

where,

$S_1$ = initial solubility of gas = $(10g)/(3L)$

$S_2$ = final solubility of gas = ?

$P_1$ = initial pressure of gas = 101.325 kPa (at STP)

$P_2$ = final pressure of gas = 200 kPa

Now put all the given values in the above formula, we get the final solubility of the gas.

$((10g)/(3L))/(S_2)=(101.325kPa)/(200kPa)$

$S_2=6.579g/L$

Therefore, the solubility of carbon monoxide gas at pressure 200 kPa is, 6.579 g/L

From which of these atoms in the ground state can a valence electron beremoved using the least amount of energy?(1) nitrogen (3) oxygen(2) carbon (4) chlorine

Answers

Carbon is the atoms in the ground state can a valence electron beremoved using the least amount of energy. Hence option 3 is correct.

What is valence electron?

Valence electron is defined as the amount of electrons an atom must earn or lose to reach the electrical configuration of the nearby noble gas or inert gas. The quantity of electrons in the outermost energy shells is known as the valence electron number. The location of an element in the periodic table corresponds to how many valence electrons are present in that element.

The least amount of energy might be used to remove the carbon valence electron. Carbon one can observe that carbon has four valence electrons in the ground state electron configuration, two of which are in the 2s subshell and two of which are in the 2p subshell.

Thus, carbon is the atoms in the ground state can a valence electron beremoved using the least amount of energy. Hence option 3 is correct.

To learn more about valence electron, refer to the link below:

brainly.com/question/12717954

#SPJ2

Carbon can-be valence electron that could-be removed using the least amount of energy.

Which of the following Group 2 elements has the lowest first ionization energy?(1) Be (3) Ca
(2) Mg (4) Ba

Answers

Barium (Ba) has the lowest first ionization energy among the given elements of group 2. Therefore, option (4) is correct.

What is ionization energy?

The ionization energy is the minimum amount of energy that is required to knock out an electron in a gaseous atom or ion. Ionization energy can also be used to estimate the strength of chemical bonds and is measured in units of electronvolts or kJ/mol.

Alkaline earth elements can lose both valence electrons to attain a noble gas configuration. So, these elements have two ionization energies. 1st ionization energy of alkaline earth metals is the energy required to remove the first electron from the neutral atom.

With increasing atomic size down the group, the valence electron gets shielded by the inner electrons. So they can easily be removed with less energy. Hence the first ionization energy of group 2 elements decreases with an increase in the atomic number or atomic size.

Therefore, Barium has the lowest first ionization energy.

Learn more about ionization energy, here:

brainly.com/question/1602374

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The elements ionization energy increases from Ba

Which elements can react to produce a molecular compound?(1) calcium and chlorine
(2) hydrogen and sulfur
(3) lithium and fluorine
(4) magnesium and oxygen

Answers

The elements that can react to produce a molecular compound is hydrogen and sulfur

Explanation

A molecular compound is formed when two or more atoms join by sharing electrons through a covalent bond.

Sharing of atoms occurs mainly between non metals.

Hydrogen ( a non metal) and sulfur(a non metal) react to form a molecular compound by sharing electron among themselves.
2 hydrogen atom bond with 1 atom sulfur to form hydrogen sulfide.

$\boxed{\left( 3 \right){\text{ Hydrogen and sulfur}}}$ can react to produce a molecular compound.

Further Explanation:

Covalent or molecular bond is formed when two or more non-metals share electrons between them. Such electron pairs are called bonding or shared pairs. The compounds formed as a result of these bonds are called covalent or molecular compounds.

Covalent bonds can be a polar covalent or nonpolar covalent bond. The bonds formed as a result of electron sharing between the atoms having some electronegativity difference between them are polar covalent bonds. HCl shows such type of bonding in it. The bonds formed when electrons are shared between the bonded atoms and these have no or slight difference in their electronegativities are called nonpolar covalent bonds. The bonds present in a $\text{CH}_4$ molecule are nonpolar covalent bonds.

Another type of bonding that occurs due to the complete transfer of electrons from one atom to the other is called ionic bonding. Such a process includes the formation of charged species called ions. Ions can have positive or negative charges on them. The charged species having a positive charge are cations while those having negative charges are anions.

(1) Calcium and chlorine

Calcium belongs to group 2A of the periodic table and is highly electropositive in nature. So it loses two electrons and forms $\text{Ca}^(2+)$ . Chlorine is highly electronegative in nature so two chlorine atoms accept the electrons donated by calcium and forms $\text{Cl}^-$ ions. Therefore $\text{CaCl}_2$ is formed which is an ionic compound.

(2) Hydrogen and sulfur

Both these atoms are nonmetals. So they share electrons with each other and as a result, a covalent or molecular compound is formed.

(3) Lithium and fluorine

Lithium belongs to group 1A of the periodic table and is highly electropositive in nature. So it loses an electron to form $\text{Li}^+$ . Fluorine is highly electronegative in nature and therefore it accepts the electrons donated by lithium and forms $\text{F}^-$ . Therefore LiF is formed which is an ionic compound.

(4) Magnesium and oxygen

Magnesium belongs to group 2A of the periodic table and is highly electropositive in nature. So it loses two electrons and forms ${\text{M}}{{\text{g}}^(2 + )}$ . Oxygen is highly electronegative in nature so it accepts the electrons donated by magnesium and forms ${{\text{O}}^(2 - )}$ . This results in the formation of MgO which is an ionic compound.

Therefore a molecular compound is formed when hydrogen and sulfur react with each other.

Learn more:

What is a typical characteristic of an ionic compound? brainly.com/question/6071838
What type of bond exists between phosphorus and chlorine? brainly.com/question/81715

Answer details:

Grade: High School

Chapter: Ionic and covalent compounds

Subject: Chemistry

Keywords: covalent bond, molecular bond, cations, anions, calcium, chlorine, hydrogen, sulfur, lithium, fluorine, magnesium, oxygen, molecular compound, ionic compound.

Corrosion is what type of chemical change? a. oxidation
b. phase change
c. physical change
d. combustive reaction

Answers

(A)Oxidation is your answer..........

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