Which reaction is an example of an endothermic reaction?

107.904 grams of O2. I believe this is correct.

Answer:

Bonds are broken and new bonds are formed during chemical reactions only.

Explanation:

So, the right choice is:

Bonds are broken and new bonds are formed during chemical reactions only.

Final answer:

Bonds are broken and new bonds are formed during chemical reactions only, not during physical changes. A chemical reaction reorganizes atoms into new substances, which involves breaking old bonds and forming new ones, fundamentally changing the composition of the reactants.

Explanation:

The true statement is that bonds are broken and new bonds are formed during chemical reactions only. During a chemical reaction, reactants undergo a transformation where their chemical bonds are broken, atoms are rearranged, and new substances with new bonds are formed, called products. This process involves energy changes, where breaking bonds requires an input of energy while forming bonds releases energy.

Conversely, physical changes involve a change in the form or physical properties of a substance, without altering the chemical composition or the bonds within molecules. Thus during chemical reactions, old bonds are broken, and new bonds form to create new substances with different chemical and physical properties; this is essential in defining a chemical change. Physical changes, on the other hand, do not involve changes in the bonds that hold atoms together within a molecule.

Answer: thermal conductivity

Explanation:

im not quite understanding your question but, What you place in water depends on the mass of the object and its boincy. some rocks have so much air in them they can actually float but usally all rocks sink to the bottem. Thinks like plastics, styrofoams and paper can usally float on the surface of the water.

Answer:

[tex]\boxed{\text{0.118 mol/L}}[/tex]

Explanation:

[tex]\text{Molar concentration } = \dfrac{\text{moles}}{\text{litres}}\\\\\text{c} = \dfrac{n}{V}[/tex]

1. Convert grams to moles.  

[tex]\text{Moles AgNO}_{3} = \text{10.0 g AgNO}_{3} \times \dfrac{\text{1 mol AgNO}_{3} }{\text{169.87g AgNO}_{3} } = \text{0.058 87 mol AgNO}_{3}[/tex]

2. Convert moles to litres  

[tex]\text{V = 500. mL} \times \dfrac{\text{1 L}}{\text{1000 mL}} = \text{0.5000 L}[/tex]

3. Calculate the molar concentration

[tex]c = \dfrac{\text{0.058 87 mol}}{\text{0.5000 L}} = \text{0.118 mol/L}[/tex]

The molar concentration of AgNO₃ is [tex]\boxed{\textbf{0.118 mol/L}}[/tex].

The molarity of a solution in which 10.0g of AgNO₃ is dissolved in 500. mL of solution is 20M.

Molarity of any solution is define as the number of moles of solute present in per liter of solution.

M = n/V, where

n = moles of solute AgNO₃ = 10g

V = volume of solution = 500mL = 0.5L

On putting values on the above equation, we get

M = 10/0.5 = 20M

Hence required molarity of solution is 20 M.

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Answer:

1.325 x 10²⁴ Co atoms

Explanation:

1 mol of any substance is made of 6.022 x 10²³ units, these units could be atoms making up elements of molecules making up a compound.

Therefore 1 mol of the element cobalt is made of 6.022 x 10²³ atoms of Co

so if 1 mol of Co contains - 6.022 x 10²³ atoms of Co

then 2.2 mol of Co contains - 6.022 x 10²³ /mol x 2.2 mol

number of Co atoms in 2.2 mol of Co is - 1.325 x 10²⁴ Co atoms

Answer:

IO₂

Explanation:

We have been given the mass percentages of the elements that makes up the compound:

Mass percentage given are:

Iodine = 79.86%

Oxygen = 20.14%

To calculate the empirical formula which is the simplest formula of the compound, we follow these steps:

> Express the mass percentages as the mass of the elements of the compound.

> Find the number of moles by dividing through by the atomic masses

> Divide by the smallest and either approximate to nearest whole number or multiply through by a factor.

> The ratio is the empirical formula of the compound.

Solution:

I O

% of elements 79.86 20.14

Mass (in g) 79.86 20.14

Moles(divide by

Atomic mass) 79.86/127 20.14/16

Moles 0.634 1.259

Dividing by

Smallest 0.634/0.634 1.259/0.634

1 2

The empirical formula is IO₂

To find the empirical formula of a compound, we calculate the moles of each element using their atomic masses. Dividing the moles by the smallest value gives us the ratio of the elements, which represents the empirical formula. For the compound containing 79.86% iodine and 20.14% oxygen, the empirical formula is IO2.

To find the empirical formula, we need to determine the simplest whole-number ratio between the elements in the compound. To do this, we first assume we have 100g of the compound, which allows us to convert the percentages to grams. We can then calculate the moles of each element using their atomic masses. The ratio of moles gives us the empirical formula.

For the given compound that contains 79.86% iodine and 20.14% oxygen by mass:

Assuming 100g of the compound, we have 79.86g of iodine and 20.14g of oxygen. The moles of iodine can be calculated using its atomic mass (126.9 g/mol), which gives us 0.628 moles. The moles of oxygen can be calculated using its atomic mass (16.0 g/mol), which gives us 1.259 moles. Dividing both moles by the smaller value (0.628 moles) gives us the ratio of 1:2. Therefore, the empirical formula for the compound is IO2.

Answer:

cornell noted

Explanation:

used in middle school and can be helpful for subjects like ela history and science

Answer:

Cornell notes

(picture attached)

Explanation:

out of the 5 methods the most popular and efficient is Cornell notes :)

↓methods↓

1)The Cornell Method.

2)The Outlining Method.

3)The Mapping Method.

4)The Charting Method.

5)The Sentence Method

×║hope this helps║×

Answer:

1. 6.45 L

2. 1.76 x 10²³ molecules

Explanation:

1. Avagadros law states that volume of gas at constant temperature and pressure is directly proportional to the amount / number of moles of that gas

we can use the following equation

v1/n1 = v2/n2

where v1 is volume and n1 is number of moles at first instance

and v2 is volume and n2 is number of moles at second instance

at the first instance - n1 = 0.218 mol

second instance - n2  = 0.218 mol + 0.075 mol  = 0.293 mol

substituting the values

4.8 L / 0.218 mol = v2 / 0.293 mol

v2 = 6.45 L

new volume is 6.45 L

2. 1 mol of any substance is made of 6.022 x 10²³ units. These units could be atoms making up elements or molecules making up a compound.

therefore if 1 mol consists of 6.022 x 10²³  molecules

then 0.293 mol consists of - 6.022 x 10²³ molecules/mol x 0.293 mol = 1.76 x 10²³ molecules

therefore there are 1.76 x 10²³ molecules now in the cylinder

Answer:

Massive

Explanation: some astroids are so large they can destroy planets.

Answer:

The answer is Varied

Explanation:

Answer:

1.12dm³

Explanation:

The reaction is a decompositon reaction. It is expressed below:

Mg(HCO₃)₂ + Heat → MgCO₃ + H₂O + CO₂

This is the balanced reaction equation.

We have 1 mole of Mg, 2 mole of H, 2 mole of C, 6 mole of O on both sides of the reaction.

To calculate the volume of CO₂ gas evolved at S.T.P:

We work from the known to the unknown.

The known is Mg(HCO₃)₂ and the unknown is CO₂

1. Find the number of moles of Mg(HCO₃)₂ from the given mass

2. Since we know that chemical reactions obey the law of conservation of mass. The balanced chemical reaction shows that, 1 mole of Mg(HCO₃)₂ would give 1 mole of CO₂

3. We use information from (2) to find the number of moles of CO₂. With the number of moles of CO₂ found, we use the formula below to find the volume evolved at S.T.P

Volume evolved =

number of moles of CO₂ x 22.4dm³mol⁻¹

Solution:

Given/known parameters:

Mass of Mg(HCO₃)₂ = 7.3g

Step 1:

Number of moles

of Mg(HCO₃)₂ = mass/molar mass

Molar mass of Mg(HCO₃)₂ :

Atomic mass of Mg = 24gmol⁻¹

H = 1gmol⁻¹

C = 12gmol⁻¹

O = 16gmol⁻¹

Molar Mass Mg(HCO₃)₂

= [24 + 2{1 + 12 + (16 x3)} ]

= 24 + 2(1 +12 + 48)

= 24 + 122

= 146gmol⁻¹

Number of moles of

Mg(HCO₃)₂ = 7.3g/126gmol⁻¹ = 0.05mol

Step 2:

We know from the balanced equation that:

1mole of Mg(HCO₃)₂ = 1 mole of CO₂

So: 0.05mol of Mg(HCO₃)₂ = ?

This would also produce 0.05mol of CO₂

Step 3:

Volume of CO₂ evolved =

number of moles of CO₂ x 22.4dm³mol⁻¹

= 0.05 x 22.4

= 1.12dm³

The volume of CO₂ gas evolved at S. T. P is 1.12dm³

The volume of carbon dioxide gas evolved at STP by heating 7.3 gram of Mg(HCO3)2 will be 1.12 L or 1120 ml

The reaction is a decomposition reaction;

From the reaction

1 mole of Mg(HCO₃)₂ produces 1 mole of CO₂ after decomposition.

Therefore, to determine the volume of CO₂ produced by 7.3 grams of Mg(HCO₃)₂

Number of moles = Mass/relative formula mass

RFM of Mg(HCO₃)₂  =146.33868 g/mol

Therefor;

Number of moles = 7.3 g/146.33868 g/mol

                             = 0.04988

                             = 0.05 moles

From the equation;

1 mole of Mg(HCO₃)₂ produces 1 mole of CO₂ after decomposition.

Therefore;

Moles of carbon dioxide produced is 0.05 moles

From molar gas volume;

1 mole of  CO₂  at STP occupies 22.4 L

Thus;

0.05 moles will occupy;

= 0.05 × 22.4 L

= 1.12 L or 1120 mL

Therefore; volume of carbon dioxide gas evolved at STP by heating 7.3 gram of Mg(Hco3)2 will be​ 1.12 L or 1120 ml

Keywords; Decomposition reactions, molar gas volume, relative formula mass, moles

Learn more about:

Level: High school

Subject: Chemistry

Topic: Moles

Sub-topic: Molar gas volume

Answer:

Explanation:

A chemical bond is a lasting attraction between atoms, ions molecules that enables the formation of chemical compound.

Answer:

D

Explanation:

Because is other stuff can form from sediments then why can't glaciers

A nuclear reaction is at its most basic nothing more than a reaction process that occurs in an atomic nucleus. They typically take place when a nucleus of an atom gets smacked by either a subatomic particle (usually a "free neutron," a short-lived neutron not bound to an existing nucleus) or another nucleus

but alot of things happen to be honest to much to put down but the basic is a blast of energy that is super heated by friction that is followd by nuclear after fall and this can be very deadly even miles away

hope this helps

Final answer:

In a nuclear reaction, the nucleus of an atom undergoes a change, often transforming into a different element or isotope and releasing tremendous amounts of energy. This energy, derived from the nuclear binding energy, is much greater than energy changes in chemical reactions.

Explanation:

A nuclear reaction is a process where the nucleus of an atom changes. This change can result in the transformation of elements through a process known as transmutation or the conversion of atoms into various isotopes. Unlike chemical reactions, where electrons are transferred or shared between atoms, nuclear reactions involve changes in the nucleus and typically release far greater amounts of energy. This energy comes from the nuclear binding energy, which binds protons and neutrons in the nucleus.

Two primary types of nuclear reactions are nuclear decay reactions and nuclear transmutation reactions. In decay reactions, an unstable nucleus emits radiation to form a more stable nucleus, while transmutation reactions occur when nuclei or subatomic particles collide and transform into a different element or isotope. These processes often produce energy orders of magnitude greater than that produced by chemical reactions, highlighting the immense power of nuclear changes.

A hypothesis is tested by conducting an experiment.

Answer: The correct answer would be A. Conducting Observation

Explanation:

Because....

If you don't conduct an experiment then how will you know if your hypothesis was true or not. So a hypothesis is tested by Conducting Observation.

* Hopefully this helps:) Mark me the brainliest:)!!

Answer:

They retain their chemical properties

Explanation:

Answer: They retain their chemical properties

Explanation:

Mixture is a substance which has two or more components which do not combine chemically and do not have any fixed ratio in which they are present.

For example: Air is a mixture which consists of various gases, water vapors and various particles in solid form which are not present in any fixed ratio, do not combine chemically and thus retain their chemical properties.

Thus the only true statement about substances in a mixture is that they retain their chemical properties

Answer:

[tex]\boxed{\text{ B. Increase the temperature and decrease the pressure.}}[/tex]

Explanation:

Let's say the reaction is

R ⇌ 2P; endothermic

I like to consider heat as if it were a reactant or a product in a chemical equilibrium.

Another way to write the equilibrium would be

heat + R ⇌ 2P

According to Le Châtelier's Principle, when a stress is applied to a system at equilibrium, the system will respond in a way that tends to relieve the stress.

Let's consider each of the stresses in turn.

(i) Changing the temperature

If you want to increase the amount of product, you increase the temperature. The system will try to get rid of the added heat by shifting to the right, thus forming more product.

(ii) Changing the pressure

If R and P are liquids or solids or in aqueous solution, changing the pressure will have no effect. Something must be in the gas phase for a change in pressure to affect the position of equilibrium.

If P is a gas, the equilibrium is

heat + R ⇌ 2P(g)

Then, decreasing the pressure will produce more P. If you reduce the pressure, the system will respond by shifting to the right (the side with more gas molecules) to produce more P and bring the pressure back up

Answer:

above is wrong

Explanation:

there are no choices of statements

The molecule Br2 is a diatomic molecule made up of two bromine atoms, which exists as a liquid at room temperature due to its size and number of electrons.

The molecule Br2, which stands for Bromine molecule consists of two bromine atoms. This molecule is unique in that it is one of the few elements that exist as a liquid at room temperature.

The bromine molecule, Br2, is a simple diatomic molecule with a single, covalent bond holding the two bromine atoms together. Due to its size and number of electrons, Br2 is heavier than many other diatomic molecules, which is why it exists as a liquid at room temperature while other diatomic molecules like O2 and N2 are gases.

This specific behavior plays a significant role in understanding the trend of molecular states. For instance, Bromine's state as a liquid at room temperature, as opposed to I2 (a solid) and Cl2 (a gas) informs us about the impact of the physical state on a molecule's entropy.

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Answer;

12 carbon atoms, 22 hydrogen atoms and 11 oxygen atoms.

Explanation:

Using a balanced chemical equation we can identify the number of carbon, hydrogen, and oxygen atoms in sugar.

CxHyOn + 12O₂  → 11 H₂O + 12CO₂

When an equation is completely balanced, then the number of each atom of an element is equal on the reactant side and the product side.

Therefore;

For carbon; x = 12

For Hydrogen; y = (11×2) = 22

For Oxygen; n + (12×2) = 11 + (12×2)

                    = n + 24 = 11 + 24

                        n = 11

Therefore the sugar has, 12 carbon atoms, 22 hydrogen atoms and 11 oxygen atoms.

Thus the balanced equation would be;

C₁₂H₂₂O₁₁ + 12O₂  → 11 H₂O + 12CO₂

Answer:

Explanation: .

Answer:

[tex]\boxed{ \text{8.40 g}}[/tex] 

Explanation:

The half-life of K-40 (1.3 billion years) is the time it takes for half of it to decay.  

After one half-life, half (50 %) of the original amount will remain.  

After a second half-life, half of that amount (25 %) will remain, and so on.  

We can construct a table as follows:  

 No. of                                 Fraction

half-lives          t/yr             Remaining  

      0               0                          1

      1                1.3  billion              ½

      2              2.6                          ¼

      3              3.9                          ⅛

We see that after 2 half-lives, ¼ of the original mass remains.

Conversely, if two half-lives have passed, the original mass must have been four times the mass we have now.

Original  mass = 4 × 2.10 g = [tex]\boxed{ \text{8.40 g}}[/tex]

Answer:

8.40 is correct

Explanation:

When baking soda, (a base) and vinegar (a acid) are mixed together, there is a chemical reaction, taking place, making the two diferent substances, one substance, that is now neutral.

Answer:

= 1.271 J/g°C

Explanation:

Heat released by the metal sample will be equivalent to the heat absorbed by  water.

But heat = mass × specific heat capacity × temperature change

Thus;

Heat released by the solid;

= 225 g × c ×(67 -53) , where c is the specific heat capacity of the metal

= 3150 c joules

Heat absorbed by water;

= 25.6 g × 4.18 J/g°C × (53-15.6)

= 4002.0992  joules

Therefore;

3150 c joules = 4002.0992 joules

c =4002.0992/3150

  = 1.271 J/g°C

The answer is B.) T /12

Answer: [tex]t_\frac{1}{2}[/tex]

Explanation:-

1. Activation energy is the extra energy required by the reactants to cross the energy barrier and convert to products. It is designated by the symbol [tex]E_a[/tex].

2. Half life is the time taken by a reactant to reduce to its original concentration. It is designated by the symbol [tex]t_\frac{1}{2}[/tex].

3. Alpha decay: In this process, alpha particles is emitted when a heavier nuclei decays into lighter nuclei. The alpha particle released has a charge of +2 units.

[tex]_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}+_2^4\alpha[/tex]

4. Beta-decay: In this process, a neutron gets converted into a proton and an electron releasing a beta-particle. The beta particle released carries a charge of -1 units.

[tex]_Z^A\textrm{X}\rightarrow _{Z+1}^A\textrm{Y}+_{-1}^0\beta[/tex]

6 moles because you start with a balanced equation and with the balanced equation it means that regardless of how many miles of nitrogen gas you have, the reaction will always consume twice as many miles if hydrogen gas.

Answer:

Explanation:

molarity is moles of solute/L solution

5.5 g                         1 moles Kl             1000 mL

_____                   *  __________    *    ________ = 0.22088 M

150 ml of solution     166 grams              1 L

       (39 grams K+ 127 grams I) ^

Answer:

[tex]\boxed{\text{0.22 mol/L}}[/tex]

Explanation:

[tex]\text{Molar concentration} = \dfrac{\text{moles}}{\text{litres}}\\\\\text{c} = \dfrac{n}{V}[/tex]

1. Convert grams to moles.  

[tex]\text{Moles KI = 5.5 g KI} \times \dfrac{\text{1 mol KI}}{\text{166.0 g KI}} = \text{0.0331 mol KI}[/tex]

2. Convert millilitres to litres  

[tex]\text{V = 150 mL} \times \dfrac{\text{1 L}}{\text{1000 mL}} = \text{0.1500 L}[/tex]

3. Calculate the molar concentration

[tex]c = \dfrac{\text{0.0331 mol}}{\text{0.1500 L}} = \text{0.22 mol/L}[/tex]

The molar concentration of KI is [tex]\boxed{\textbf{0.22 mol/L}}[/tex].

Answer: No

Explanation:

A non-renewable resource is the one which cannot be replenish when once used. They are expected to short out of supply because of the fact that with the increasing population worldwide the demand for the resources will also increase. As a result of this the population may face scarcity of resources in future. Such resources cannot be expected to be used sustainably as they get completely used up in a single use. For example fossil fuels like coal, petroleum and natural gas.

No, the nonrenewable resources can be used sustainably because the nonrenewable resources are the limited.

The renewable resources the resources which are naturally replenish themselves and the  nonrenewable resources will not replenish. The  nonrenewable resources are have limit in the supply and which cannot be used sustainably. The not all the renewable energy is the sustainable energy.

The non-renewable resources of the energy are release the harmful greenhouse gases to atmosphere, this will cause the global warming. The non-renewable sources of the energy are very harmful pollutants and will cause the habitat destruction. Therefore, the nonrenewable resources can not be used as sustainably.

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Answer:

Planet: The object orbits the sun

Not planet: The object is a satellite

Planet: The regions surrounding the object are free from debris

Not Planet: The object is triangular in shape.

Explanation:

A planet is characterized as:

Spheroidal (or at least big enough to be round-ish)

It should orbit the sun (not other planets, so satellites like the moon is not considered as a planet)

It should have no debris, or cleared of debris around its orbit

Although there is now the dwarf planet category, it satisfies almost all charateristics to be considered a planet, except the cleared of debris part.

Answer:

Planet: The object orbits the sun

Not planet: The object is a satellite

Planet: The regions surrounding the object are free from debris

Not Planet: The object is triangular in shape.

Answer:

C. copper.

Explanation:

It is oxidation sate is changed from (+5) in the reactants (NO₃⁻) to (+4) in the products (NO₂). N gains 1 electron

So, it is reduced.

It is oxidation sate is the same (-2) in the reactants (NO₃⁻) and (-2) in the products (NO₂).

So, it is neither be oxidized nor reduced.

It is oxidation sate is changed (0) in the reactants (Cu) to (+2) in the products (Cu²⁺). Cu loses 2 electrons.

So, it is oxidized.

It is oxidation sate is the same (+1) in the reactants (H⁺) and (+1) in the products (H₂O).

So, it is neither be oxidized nor reduced.

Final answer:

To find the number of phosphorus atoms in 4.90 mol of copper(II) phosphate, first calculate the number of moles of phosphorus atoms in copper(II) phosphate follow by using Avogadro's number to convert moles to atoms. The total number of phosphorus atoms in 4.90 mol of copper(II) phosphate is 5.90 x 10²⁴ atoms.

Explanation:

To find the number of phosphorus atoms in 4.90 mol of copper(II) phosphate, first calculate the number of moles of phosphorus atoms in copper(II) phosphate: 2 mol of phosphorus atoms per 1 mol of Cu₃(PO₄)₂. So, 4.90 mol of Cu₃(PO₄)₂ would contain 2 * 4.90 = 9.80 mol of phosphorus atoms. Then, use Avogadro's number to convert moles to atoms: 9.80 mol * 6.022 x 10²³ atoms/mol = 5.90 x 10²⁴ atoms of phosphorus.

Answer:

A Bronsted-Lowry acid like and Arrhenius acid is a compound that breaks down to give an H+ in solution. The only difference is that the solution does not have to be water. ... An Arrhenius base is a molecule that when dissolved in water will break down to yield an OH- or hydroxide in solution.

Explanation: