Which situation is an indication that a chemical change has occurred?
A.No heat is released.
B.A gas is formed.
C.No color change occurs.
D.The temperature does not change.

Answer:

Single Replacement reaction

Explanation:

Reaction Given:

            2Na + 2HCI ------> H₂ + 2NaCl

Type of reaction = ?

Solution:

Look at the reactants and products of the reaction to know the type of reaction

           2Na + 2HCI ------> H₂ + 2NaCl

In this reaction two reactant combine and give 2 products.

Reactant of the reaction

Na = Sodium

HCl = Hydrochloric acid

Product of the reaction

NaCl = sodium chloride

H₂ = hydrogen gas

So,

That sodium metal react with hydrochloric acid and produce salt and water gas

Type of Reaction:

This is a Single Replacement reaction, in which Sodium metal (Na) replace the Hydrogen (H) of the other compound and form Sodium Chloride salt (NaCl)  and hydrogen liberate in the form of gas.

Answer:

10 electrons

Explanation:

Answer:

The answer is: 10 electrons

Explanation:

Answer:

Na+ e- - Na

Explanation:

Answer :the electrolytes conduct electricity due to movement of ions (cations and anions), while the conductors conduct electricity due to movement of electrons only.

Explanation:

Answer:

1. Double displacement reaction

2. precipitation reaction.

Explanation:

Part 1

Reaction Given:

          CH₃COOH + NaHCO₃ -----> CO₂ + H₂O+ Na⁺ + CH3COO−

Reaction Type = ?

Solution:

In this reaction two reactant combine and give 3 products.

This reaction occur in two steps

In step one acetic acid react with sodium bicarbonate and gives sodium acetate plus carbonic acid.

         CH₃COOH + NaHCO₃ -------> H₂CO₃ + CH3COONa

So, the above reaction is a double displacement reaction. where sodium of sodium carbonate replace hydrogen of acetic acid and vice versa.

In step two the cabonic acid decomposes in two components that is carbon dioxide and water.

         H₂CO₃ -----------> CO₂ + H₂O

The overall reaction is

      CH₃COOH + NaHCO₃ -----> CO₂ + H₂O + CH3COONa

As the CH3COONa exist in ions in solution so it can be written as

     CH₃COOH + NaHCO₃ -----> CO₂ + H₂O + CH3COO⁻ Na⁺

So, the overall reaction is a double displacement reaction.

This is a double displacement reaction, in which Hydrogen (H) of the first compound replace the Sodium (Na) of the other compound.

_________________

Part 2.

Reaction Given:

          CaCl₂ + 2 NaHCO₃ -------→ CO₂ + CaCO₃ + 2 NaCl + H₂O

Solution

In this reaction two reactant combine and give 4 products.

Reactant of the reaction

CaCl₂  = calcium chloride

NaHCO₃ = sodium bicarbonate

Reactant of the reaction

CO₂= carbon dioxide

CaCO₃ = calcium carbonate

NaCl = sodium chloride

H₂O = water

So,

the reactant of the reaction that is calcium chloride react with sodium bicarbonate combine and form calcium carbonate and salt along with water and the evaluation of carbon dioxide.

As in this reaction calcium carbonate is formed in the form of precipitates so it is a precipitation reaction.

So

This is a type of precipitation reaction.

Answer:

Because of its malleability.

Explanation:

Magnesium is alkaline earth metal.

It is present in second group.

It is shiny gray color metal.

It is lighter but strong.

Its density is 1.738 g/mL.

It is soft and can be malleable. Magnesium ribbons are also formed by stretching the magnesium metal and this is due to the malleability of magnesium.

Magnesium ribbon burns and produces heat.

It is used to make the many light weight products such as many parts of car,  phone, laptop, luggage etc.

It is also used to remove the sulfur such as from iron and steel.

It is also used in fireworks.

It is also used in medicine such as for constipation.

It is used as antiacid for heart burn.

Answer:

Both are endothermic reactions.

Explanation:

Chemical equation:

1/2H₂(g) + 1/2I₂(g)  →  HI(g)  + 6.2 kcal/mol

Chemical equation:

21.0 kcal/mol + C(s) + 2S(s)  → CS₂

Both reaction are endothermic because heat is added in both of reactions.

Endothermic reactions:

The type of reactions in which energy is absorbed are called endothermic reactions.

In this type of reaction energy needed to break the bond are higher than the energy released during bond formation.

For example:

C + H₂O   →  CO  + H₂

ΔH = +131 kj/mol

it can be written as,

C +  H₂O  + 131 kj/mol  →  CO  + H₂

Exothermic reaction:

The type of reactions in which energy is released are called exothermic reactions.

In this type of reaction energy needed to break the bonds are less than the energy released during the bond formation.

For example:

Chemical equation:

C + O₂   →  CO₂

ΔH = -393 Kj/mol

it can be written as,

C + O₂   →  CO₂ + 393 Kj/mol

Answer:

24 hours

Explanation:

Frozen foods are foods that were put in a refrigerator. The essence of putting food in a refrigerator is to lower the rate at which microbes cause the spoilage of the food by lowering its temperature considerably.

After 24 hours, microbes must have commenced action on non-frozen ready to eat foods causing them to spoil in not more than 24hours.

Non-frozen ready-to-eat foods should be consumed within : 24 hours

Non-frozen foods are to be consumed within 24 hours, because microbes that causes the spoilage of foods starts acting on ready-to-eat foods, after 24 hours. ready-to-eat foods are foods are processed foods that can be consumed immediately. example : smoked fish and salads

Frozen foods are refrigerated in order to keep the temperatures of the foods below the allowable temperature in which microbes tend to act on ready-to-eat foods.

Hence we can conclude that Non-frozen ready-to-eat foods should be consumed within 24 hours.

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Answer:

vot. tofu p f focpxe9d3dotc

Explanation:

circeicirct pupdtoxkr

Final answer:

Despite having strong C-H and C-Cl bonds, dichloromethane is liquid due to strong dipole-dipole intermolecular forces and van der Waals forces resulting from its considerable dipole moment and molecular size.

Explanation:

The question asks why dichloromethane is a liquid despite having strong carbon-hydrogen (C-H) and carbon-chlorine (C-Cl) bonds. While the individual molecular bonds within dichloromethane are indeed strong (due to significant differences in electronegativity between carbon, hydrogen, and chlorine), the phase state (gas, liquid, or solid) of a substance at room temperature depends on the intermolecular forces between its molecules, not just the strength of the bonds within individual molecules. Dichloromethane, having a considerable dipole moment due to its polar C-Cl bonds, exhibits stronger intermolecular forces known as dipole-dipole interactions. These interactions, though weaker than covalent bonds, are significantly strong enough to keep the molecules close together in a liquid state at room temperature. Additionally, the molecular weight and size of dichloromethane contribute to stronger van der Waals forces (or London dispersion forces), which further supports its liquid state. Unlike smaller molecules that might be gases at room temperature, dichloromethane has just the right balance of molecular weight and intermolecular forces to exist as a liquid.

Answer:

Synthesis

Explanation:

Reaction Given:

        NH₃+ HCI ------> NH₄Cl

Type of reaction = ?

Solution:

Look at the reactants and products of the reaction to know the type of reaction

          NH₃+ HCI ------> NH₄Cl

In this reaction two reactant combine and give 1 products.

Reactant of the reaction

NH₃ = Ammonia

HCl = Hydrochloric acid

Product of the reaction

NH₄Cl = Ammonium chloride

So,

That ammonia (NH₃) react with Hydrochloric acid (HCl) and produces salt.

in this reaction NH₃ is a week base and take a proton from HCl and form ammonium ion and Cl ion. these two ions in combine form gives a salt called ammonium chloride.  

Type of Reaction:

This is type of synthesis reaction, in which NH₃ and HCl combine and form a new compound that is ammonium chloride salt (NH₄Cl). As the synthesis reaction is that reaction in which two are more compounds or molecules combine and form a new compound.

Answer:

0.1 mol

Explanation:

Number of mole= mass/molar mass

lithium have a mass number of 7 and oxygen have a mass number of 16.

so, (7x2) + 16

= 30

therefore, number of moles = 2.93/30

= 0.10

Answer:

Mass of Li2O = 2.93g

Molecular mass of Li2O = 29.88g/mol

No of mole of Li2O = Mass/Molar mass

No of mole of Li2O = 2.93/29.88

No of mole of Li2O = 0.0981mol

Answer: 0.0000332mol

Explanation: 1mole of CCl4 contains 6.02x10^23 molecules.

Therefore, X mol of CCl4 will contain 2 x 10^19 molecules i.e

Xmol of CCl4 = 2 x 10^19/ 6.02x10^23 = 0.0000332mol

Answer:solid

Explanation:

Answer:

It is a solid because leafs aren't made of water or gas.

A clear prediction of the anticipated results in an experimental design is known as "Hypothesis".

Explanation:

A theory or hypothesis are often used clearly as a suggested event descriptive one. The scientific methods need that one can be able to examine for a hypothesis termed as scientific hypothesis.

A working in hypothesis is a proposed provisionally accepted hypothesis for on-going research that starts with an appropriate amount of conclusion and thoughts, also known as "Educated Guess".

According to researchers like Schick and Vaughn the weighing up an alternative hypotheses might be taken into understanding like Parsimony, testability, Fruitfulness, Scope and Conservatism.

Answer:

                    0.412 Kg of Solution

Explanation:

                    To solve this problem we will first find the number of grams of solute contained by the given amount of solution as,

                      w/w%  =  weight of solute / weight of solution × 100

Solving for weight of solute,

                      Weight of solute = w/w% × weight of solution / 100

Putting values,

                      Weight of solute = 10.9 × 500 g / 100

                       Weight of solute = 54.5 g

Hence,

                  54.5 g of solute was contained by  =  500 g of solution

So,

               45.0 g of solute will be contained by  =  X g of solution

Solving for X,

                     X =  45.0 g × 500 g / 54.5 g

                      X =  412.84 g

Or,

                     X  =  0.412 Kg of Solution

Final answer:

To obtain 45.00g of 4-methyl-2-pentanone from a 10.9% w/w solution, the student should measure out 412.84g of the solution.

Explanation:

To calculate the mass of the solution the student should use to get 45.00g of 4-methyl-2-pentanone from a 10.9% w/w solution, we first need to understand what a w/w solution means. It indicates that for every 100g of solution, there is 10.9g of the solute (4-methyl-2-pentanone). To find the mass of the solution needed for 45.00g of the solute, the following calculation should be performed:

Mass of solute (desired) = % w/w × mass of solution
Therefore, mass of solution = Mass of solute (desired) / % w/w

So:

Mass of solution = 45.00g / 0.109 = 412.84g

The student should therefore measure out 412.84g of the 10.9% solution to obtain 45.00g of 4-methyl-2-pentanone.

Answer:

7

Explanation:

Answer:

in ibs it is 1.918e-5 ibs

Explanation:

Answer:  

I had to do some research, because I not familiar with Hess's Law.

Hope this helps :)

Stating Hess's Law

Hess's Law is the most important law in this part of chemistry. Most calculations follow from it. It says "The enthalpy change accompanying a chemical change is independent of the route by which the chemical change occurs."

Explaining Hess's Law

Hess's Law is saying that if you convert reactants A into products B, the overall enthalpy change will be exactly the same whether you do it in one step or two steps or however many steps.

Answer:

Hess's Law of Constant Heat Summation (Hess's Law) states that regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes

Explanation:This law is a manifestation that enthalpy is a state function.

Explanation:

given

mass =85*1000=85000kg

volume=850/100*100*100m3

now,

density=mass / volume

=85000kg/850000000m3

=1/10000kg/m3

=0.0001kg/m3

the density of the rock is 0.0001kg/m3.

Answer:

the temperature difference between the water and the ice cubes causes heat to be transferred from the water to the ice cubes,.

Explanation:

Heat always travels to where it is colder. Think about how ice cubes melt. They are very cold so the heat is transferred to them from he warmer water and they melt.

hope this helps! i would really appreciate brainliest :)

Answer:

temperature hear

Explanation:

Answer:

ivy growing around the pole of a fence

Explanation:

Answer:

The answer is B.

Explanation:

This type of bond is formed when the electrons are shared equally between the atoms. This type of bond is termed as non-polar because of the electronegativity difference between the atoms is negligible.

The electrons in a bond between two iodine atoms are shared equally, resulting in a nonpolar covalent bond because both atoms have the same electronegativity and pull on the electrons to the same extent.

The electrons in a bond between two iodine atoms (I2) are shared equally, and since both atoms have the same electronegativity, they pull on the electrons to the same extent. This lack of asymmetry in the electrical charge distribution means that the resulting bond is nonpolar. Therefore, the correct answer to the question is: b. Equally, and the resulting bond is nonpolar.

When atoms like iodine, which are identical, form a covalent bond, they have the same tendency to attract shared electrons, resulting in an even distribution of electron density. This equal sharing of electrons characterizes a nonpolar covalent bond.

Answer:

More energy will be released from the old substance than the new substance will need to form it's chemical bonds.

Explanation:

Given

Chemical A and Chemical B react in an exothermic reaction.

This means energy is released when they react to give products. The product formation also requires energy, which is got from the energy released when A and B reacts. The energy that is left after the formation of products is released as heat. So in order for a reaction to be exothermic, the energy released  by the reactants should be more than the energy required for the new chemical bonds to be formed to give the products.

Answer:

I think B correct me if im wrong

Explanation:

hope i helped

Answer

The mole ratio is 1:1

The molar mass of potassium hydrogen phthalate (C8H5KO4) is 204.22g/mol

The mass of C8H5KO4 is 0.43g

The no of moles of C8H5KO4 = mass/molar mass

No of Moles of C8H5KO4 = 0.000210557242mol

From Mole ratio the no of mole of NaOH that reacted with C8H5KO4 0.000210557242

Therefore, molaroty of NaOH is mole of NaOH/the Volume in L

Molaroty if NaOH = 0.000210557242/0.02411 = 0.08733M

Answer:

d  v&n

Explanation:

its on edge!

Proportionality that applies to avogadro's law is V is propportional to n.

According to Avogadro's law, equal volumes of various gases each contain an equal amount of molecules at the same temperature and pressure. On the presumption of an ideal (perfect) gas, this experimental relation can be deduced first from kinetic theory of gases. For actual gases, the law is roughly applicable when temperatures and pressures are both low enough.

Avogadro's number, or even the Avogadro constant, is the precise quantity of molecules inside one gram-mole of such a material, defined as that of the molecular weight metric grams, which is equal to 6.022×10²³.

To know more about Avogadro's law here

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Answer:

A proton has positive charge of 1, that is, equal but opposite to the charge of an electron. A neutron, like the name implies, is neutral with no net charge. The charge is believed to be from the charge of the quarks that make up the nucleons (protons and neutrons). need a pictur of the question

Explanation:

Answer:

The sodium atom becomes a positive ion and the chlorine atom becomes neg.

Explanation:

Think about this answer

Answer: 4.5 x 10e-7

Explanation: 450 x 1e+9 = correct answer

Multiply amount of nanometers by 1e+9 to get the approximate result in meters.

To convert 450 nanometers to meters, you multiply 450 by 10^-9 to give 4.5 x 10^-7 meters. This places it within the blue light section of the visible spectrum.

To convert a measurement from nanometers (nm) to meters (m), we should recall that 1 nanometer is equal to one billionth of a meter, or 10^-9 m. Therefore, to convert 450nm to meters, you multiply 450 by 10^-9 which gives you the answer of 4.5 x 10^-7 meters. That places it well within the visible spectrum of the electromagnetic spectrum, between 380nm and 740nm, specifically in the blue light range.

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Explanation:

mass of an object affect the density and object if the the volume is keep constant.

here we can explain by using the example.

if the mass of an object is 30kg. and volume is 2m3

then density pf given substance is become 15kg/m3

again,

if the mass of the is 40kg/m3 and volume is same

then density is become 20kg/m3 (formula=kg/m3)

here above density and below density is becime different by changing the mass of an object and affect the density and objecy although volume is kept constant or same

Answer: An increase in mass will increase the density

A decrease in mass will decrease the density

Explanation: So any changes in the mass of the object will affect its density even with constant volume. Mass is directly proportional to density. So when mass is increased density will increase as well and vice versa.

Answer:

Option A is correct: You have three times the number of particles that are in 12 grams of carbon-12

Explanation:

Data given:

3 moles of substance equal to how many particles of 12 g of carbon-12.

Solution:

First we find the number of particles in 3 moles of substance

Formula used

          no. of moles = no. of particles / Avogadro's number

Rearrange the above formula

         no. of particles = no. of moles x Avogadro's number . . . . . . . . (1)

Where

Avogadro's number = 6.022 x 10²³

Put values in above equation

      no. of particles = 3 x 6.022 x 10²³ (particles/mol)

      no. of particles = 1.8066 x 10²⁴ Particles

So,

3 mole of substance have 1.8066 x 10²⁴ Particles

Now

we have to find number of particles in 12 g of carbon-12

for this first find no. of moles

formula used

       no. of moles = mass in grams/ molar mass . . . . . (2)

molar mass of carbon = 12 g/mol

Put values in equation 2

       no. of moles = 12 g / 12 (g/mol)

       no. of moles = 1 mole

So,

12 g of carbon 12 equal to 1 mole.

According to Avogadro's law 1 mole of any substance consists of 6.022 x 10²³ number of particles.

So

1 mole carbon = 6.022 x 10²³ particles

and 3 mole of substance = 1.8066 x 10²⁴ Particles

It means that we have three times number of particles that are in 12 g of carbon-2

So, Option A is correct.

A. You have three times the number of particles that are in 12 grams of carbon-12.