Complete the following sentences:

a In an exothermic reaction, the energy transferred to the surroundings from forming new bonds is _______ than the energy needed to break existing bonds.  

b In an endothermic reaction, the energy transferred to the surroundings from forming new bonds is _______ than the energy needed to break existing bonds.  

c The energy change of an exothermic reaction has a ____________ sign.  

d The energy change of an endothermic reaction has a ____________ sign.  


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Explanation:

Minerals should be found in nature. Elements made laboratories are not actual minerals like masquerading as rubies or sapphires. All naturally available crystals are not minerals like opal and amber.

Minerals are not under any class of organic compounds. Almost all known minerals come from inorganic processes. Some minerals originate from organic processes like pearls.

Minerals exist only as solids. Solids have a defined volume and shape, and they cannot be compressed any further. Minerals are rigid.

Each mineral has a unique combination of atoms that cannot be found in other minerals. The strength of mineral can be defined by the type of bond a mineral has. Some minerals, like gold and diamond, have only one element in it.

Minerals form crystals that have repeated arrangements of ions. Minerals have different shapes depending on the size of the ion. Crystals usually take six types of shapes.

Answer:

2.42L

Explanation:

Given parameters:

V₁  = 1.8L

T₁ = 293K

P₁  = 101.3kPa

P₂ = 67.6kPa

T₂  = 263K

Unknown:

V₂ = ?

Solution:

To solve this problem, we are going to use the combined gas law to find the final volume of the gas. The combined gas law expression combines the equation of Boyle's law, Charles's law and Avogadro's law;

               [tex]\frac{P_{1} V_{1} }{T_{1} } = \frac{P_{2} V_{2} }{T_{2} }[/tex]

All the units are in the appropriate form. We just substitute and solve for the unknown;

         101.3 x 1.8 / 293    =     67.6 x V₂  /  263

          V₂   = 2.42L

Answer:

Option C. $1.79

Explanation:

From the question, were told that the total cost of 8 protein bar is $14.32.

Therefore, the cost of 1 protein bar will be = $14.32/8 = $1.79

Answer:

That makes Dimagnesium phosphate

Answer:

The reaction between Magnesium and Hydrogen Phosphate forms Magnesium Hydrogen Phosphate

Explanation:

When magnesium reacts with hydrogen phosphate it forms an ionic compound called Magnesium Hydrogen Phosphate or Dimagnesium Phosphate.

Magnesium Hydrogen Phosphate is an ionic compound with the formula HMgO4P.

Equation;

Mg + HPO4 ------> HMgO4P

Similarly we can use Magnesium Phosphate to demonstrate the reaction.

In chemistry, the sum of charges of the anion and the cation of any ionic compound is always equal to zero.

To determine the number of anion and cation required for the sum to be zero we simply use the criss-cross method. This involves taking the charge of one ion and making the absolute value of that charge to be the amount of the other ion.

Therefore, Magnesium having a charge of 2+; we will have two(2) Phosphate cations for it.

Also, Phosphate has a charge of 3-; so we have three(3) Magnesium cations.

Equation;

[tex]Mg^{2+} + (PO4)^{3-} ----> Mg3(PO4)2[/tex]

Answer:

sodium atom

Explanation:

the sodium ion loses a valence shell when it ionizes. The sodium atom retains this valence shell which adds to its radius

The first ingredient to run out would be the chocolate chips.

A limiting reactant is a reactant that determines the amount of product that would be formed in a reaction.

In this scenario, the ratio of flower to chocolate chips to sugar to milk for a 100 cookies is 1:100:1:0.5.

The ratio of the same ingredients bought in the store is  5:300:6:16

Note: 16 cups = a gallon

To the lowest ratio: 5:300:6:16 = 1:60:1.2:3.02

Since the ratio of flour to chocolate chips is 1:100, it means that the chocolate chips would be the first to run out first and thus, the limiting reactant.

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Sunlight/light from the sun

Answer:

I'm pretty sure it's B

Explanation:

Blood flung off swinging objects creates a type of spatter known as cast-off, different from arterial spray, expirated blood patterns, or void patterns. Option C is correct.

Blood that is flung off of swinging objects creates a type of spatter known as cast-off. This typically occurs when blood on an object, such as a weapon, is flung into the surrounding area when the object is quickly swung or moved.

It can be distinguished from other types of spatter, such as arterial spray, which is characterized by the pulsating pattern of blood that spurts out with each heartbeat, or expirated blood patterns, which are caused by blood that is expelled from the mouth or nose from an internal injury. Void patterns occur when an object blocks the deposition of blood spatter onto a surface or object, creating a blank space within the bloodstained area.

Hence, C. is the correct option.

Answer:

mg3n2

Explanation:

Answer:

3Mg + N2 —> Mg3N2

Explanation:

The reaction between Mg and N2 is given below:

Mg + N2 —> Mg3N2

Now let us balance the equation:

There are 3 atoms of Mg on the right side and 1atom on the left side. It can be balance by putting 3 in front of Mg as shown below:

3Mg + N2 —> Mg3N2

Now the equation is balanced

The decrease in the volume of gas at constant pressure results in the final temperature of the gas is 115.05 K.

The Charles law states that with the gas constant pressure there has been a proportional relationship between the volume and temperature.

At constant pressure, the relationship between the temperature and volume can be given by:

[tex]\rm \dfrac{Initial\;volume}{\Initial\;Temperature}\;=\;\dfrac{Final\;Volume}{Final\;Temperature}[/tex]

For the given gas, the final temperature can be calculated as:

[tex]\rm \dfrac{350\;ml}{298.15\;K}\;=\;\dfrac{135\;ml}{Final\;temperature}[/tex]

1.173 = [tex]\rm \dfrac{135\;ml}{Final\;temperature}[/tex]

Final temperature = [tex]\rm \dfrac{135\;ml}{1.173\;K}[/tex]

Final temperature = 115.05 K.

The reduction in the volume of gas at constant pressure results in the final temperature of the gas is 115.05 K.

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Using Charles's Law, we can calculate that the final temperature of the gas at constant pressure when its volume is decreased from 350 mL at 25°C to 135 mL is -157.95°C.

The student is asking about the relationship between the volume and temperature of a gas held at constant pressure, which can be described using Charles's Law. According to this law, at constant pressure, the volume of a gas is directly proportional to its absolute temperature (measured in Kelvin). To find the final temperature when the volume of 350 mL of gas at 25°C is decreased to 135 mL, we can set up the proportion:

V1 / T1 = V2 / T2

where:

First, we need to convert the initial temperature from Celsius to Kelvin by adding 273.15 (T1 in Kelvin is 298.15 K). Then we can solve for T2:

(350 mL / 298 K) = (135 mL / T2)

Multiplying both sides by T2 and then by 298 K, we get:

T2 = (135 mL * 298 K) / 350 mL = 115.2 K

Converting back to Celsius, we subtract 273.15 from 115.2 K to get -157.95°C, which is the final temperature of the gas at constant pressure.

Answer: Elements in the same column are similar in their properties

Explanation: The columns on the periodic table are also know as group of the periodic table elements in the same group of the periodic table tends to have similar chemical properties because they all have the same number of valence electrons in their outermost shell. This plays an important roles in their reactivity and properties

Answer:

1. elements in the same column are similar in their properties

Explanation:

I got it right :)

Answer:

Color is emitted from an atom when an electron jumps from a higher energy level to a lower energy level

Explanation:

According to Bohr's model of the atom, electrons are arranged into circular orbits, each orbit corresponding to a precise energy level.

In this model of the atom, electrons cannot be between two orbits: this means that the energy level of the atom are discrete, so they can only assume certain values.

As a result, when an electron jumps between two energy levels, it emits/absorbs a photon whose energy is equal to the difference in energy between the two levels.

In particular:

- If an electron jumps from a lower energy level to a higher energy level, it absorbs a photon

- If an electron jumps from a higher energy level to a lower energy level, it emits a photon

The energy of the emitted photon is equal to the difference in energy between the two levels, and it is related to the wavelength [tex]\lambda[/tex] of the photon by

[tex]E=\frac{hc}{\lambda}[/tex]

where h is the Planck's constant and c the speed of light.

For usual gases, the value of the energy E is such that the value of the wavelength [tex]\lambda[/tex] falls within the visible light range of the electronmagnetic spectrums, so we observe light emitted as different colors, depending on the wavelength.

Answer:

Anything in the environment that causes a change is called a stimulus.

Explanation:

Answer:

Anything in the environment that causes a change is called a stimulus.

Explanation:

Organisms react to many stimuli, including light, temperature, odor, sound, gravity, heat, water, and pressure. The ability of living things to react to stimuli is known as irritability.

Answer:

1.54x10^24

Explanation:

To convert moles to molecules, multiply the number of moles by Avagadro's number (6.02x10^23).

2.56mol × 6.02x10^23 = 1.54x10^24

To find the number of molecules in 2.56 moles of water, we multiply the number of moles (2.56) by Avogadro's number (6.022 x 10²³), resulting in 1.54 x 10²⁴ molecules of water.

The question asks, what are the number of molecules in 2.56 moles of water? To answer this, we need to understand Avogadro's number, which is a fundamental concept in chemistry representing the number of units in one mole of any substance. Specifically, Avogadro's number is 6.022 x 10²³. Therefore, to find the number of molecules in 2.56 moles of water, we multiply the number of moles by Avogadro's number:

This calculation gives us: 1.54 x 10²⁴ molecules of water in 2.56 moles.

Answer:

Answer of question a is 345J.

Explanation:

In question a following is given in data:

-mass of iron (m) = 10.0 g

-temperature (ΔT) = final temperature- initial temperature= 100-25=  75 degree Celsius

-Specific Heat capacity of iron (c)= 0.46J/g°C.

Heat (Q)=?

Solution:

Formula for Heat is :

Q=m x c x ΔT

Q= 10 x 0.46 x 75

Q= 345 J.  

so, 345 joules of heat is needed to increase the temperature of 10 grams of iron.

To find the amount of heat required or released, use the formula q = m × c × ΔT, applying the given values for mass, specific heat capacity, and temperature change.

To solve the heat calculation problems, we use the formula q = m × c × ΔT, where q is the heat absorbed or released, m is the mass of the substance, c is the specific heat capacity of the substance, and ΔT is the change in temperature (final temperature minus initial temperature).

For example, to calculate how much heat is required to raise the temperature of 10.0 g of iron from 25°C to 100.0°C, given that the specific heat capacity of iron is 0.46 J/g°C, we apply the formula: q = (10.0 g) × (0.46 J/g°C) × (100.0°C - 25°C). Calculating this gives q = 345 J, meaning 345 Joules of heat is required.

It is an example of a binary compound.

Answer:

Change in volume on changing temperature from 33[tex]^{\circ}C[/tex] to 5[tex]^{\circ}C[/tex] is 5.49 mL

Explanation:

Initial volume of gas = V = 60 mL

Assuming final volume of gas to be V' mL

Initial temperature = T = 33[tex]^{\circ}C[/tex] = 306 K

Final temperature = T' = 5[tex]^{\circ}C[/tex] = 278 K

The relationship between volume and temperature of gas at constant pressure is shown below

[tex]\displaystyle \frac{V}{V'}=\displaystyle \frac{T}{T'} \\\displaystyle \frac{60\textrm{ mL}}{V'} = \displaystyle \frac{306\textrm{ K}}{T} \\V' = 54.51 \textrm{ mL} \\\textrm{Change in volume} = \left ( V-V' \right ) \\\textrm{Change in volume} = \left ( 60-54.51 \right )\textrm{ mL} \\\textrm{Change in volume} = 5.49 \textrm{ mL}[/tex]

Change in volume on changing temperature = 5.49 mL

Answer: oxygen=2.547g

Explanation:

Based on the question,it was observed that the reaction is reversible

2 moles of KClO3 gives 2 moles of KCl and three moles of O2

Molar mass for KClO3 is 245 g/mol

Molar mass for O2 is 96 g/mol

We are to find the mass of O2 and we Are given the mass KCLO3 is 6.50g

245g of KClO3 gives 96g of O2

6.50g of KClO3 gives xg of O2

Cross multiply

245x=624

X=624/245

X=2.547g

Therefore the gram of oxygen is 2.547g

When 6.50 grams of potassium chlorate (KClO3) are heated, approximately 2.54 grams of oxygen gas should be given off.

When potassium chlorate (KClO3) is heated, it decomposes to produce potassium chloride (KCl) and oxygen gas (O2). The balanced chemical equation for this reaction is:

2KClO3(s) → 2KCl(s) + 3O2(g)

In order to determine the amount of oxygen gas produced, we need to calculate the theoretical yield of oxygen gas. This can be done using stoichiometry and the molar mass of KClO3.

First, calculate the molar mass of KClO3:

39.10 g/mol (K) + 35.45 g/mol (Cl) + 3(16.00 g/mol) (O) = 122.55 g/mol

Next, use the molar mass of KClO3 to convert grams of KClO3 to moles:

6.50 g KClO3 * (1 mol KClO3 / 122.55 g KClO3) = 0.053 mol KClO3

According to the balanced chemical equation, 2 moles of KClO3 produce 3 moles of O2. Therefore, the number of moles of O2 produced can be calculated as:

0.053 mol KClO3 * (3 mol O2 / 2 mol KClO3) = 0.0795 mol O2

Finally, convert moles of O2 to grams:

0.0795 mol O2 * (32.00 g/mol O2) = 2.54 g O2

Therefore, when 6.50 grams of KClO3 are heated, approximately 2.54 grams of oxygen gas should be given off.

Answer:

B

Explanation:

Mutations that increase an organism's ability to survive and reproduce in its environment are more likely to be passed on to future generations. This core principle is known as survival of the fittest.

The concept of survival of the fittest is closely related to the idea of mutations. Mutations are changes in an organism's DNA that can lead to new traits. The best way to describe how mutations relate to survival of the fittest is to say that a mutation that allows an organism to survive and reproduce more successfully in its environment is more likely to be passed on to future generations.

Thus, option B is the correct answer: 'A mutation that allows organisms to survive is more likely to be passed on'. Not all mutations are beneficial, some can be harmful or neutral, but only those mutations that increase an organism's fitness — its ability to survive and reproduce — are likely to be passed on.

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Answer :

the amount of heat,in joules, required to increase the temperature of a 49.5-gram sample of wanted from 22°c to 66°c is 9.104 Joules.

Explanation:

The answer can be calculated using the formula

Q = mCрΔT

where

Q is the amount of heat required in joules to raise the temperature.

m is the mass of the sample in Kg.

Cp is the specific heat of the sample in J/Kg°C.

ΔT is the change in temperature required.

Here, m = 49.5-gram = 0.0495 kg

Cp = 4.18 J/Kg°C (for water)

T₁ = 22°C  ; T₂ = 66°C

ΔT =  66 - 22 = 44

Substituting values in Q = mCрΔT

Q = (0.0495)(4.18)(44)

                  Q = 9.104 J

Answer:

Explanation:

An acid is a substance that interacts with water to produce excess hydroxonium ions in an aqueous solution.

An electrolyte is a compound which breaks up into ions when dissolved in water or when in molten form.

A strong acid is one that ionizes almost completely ion aqueous solution.

To make a strong electrolyte, there must be presence of ions from compounds that ionizes completely in aqueous solution or in molten form to give free mobile ions. This is why strong acids are very strong electrolytes too.

2. Other examples of strong electrolytes are mineral acids, caustic alkalis and salts because they also ionize completely in aqueous solutions. Any compoud that ionizes completely in aqueous solution will produce a strong electrolyte.

Strong acids are considered strong electrolytes because they completely ionize in solution, producing a high concentration of ions which makes them good conductors of electricity. However, not all strong electrolytes are strong acids; other substances like strong bases and salts can also be strong electrolytes.

Strong acids, such as hydrochloric acid (HCl), are also strong electrolytes because they ionize completely in aqueous solution, meaning they release all their hydrogen ions (H*). This leads to a high concentration of ions, making them excellent conductors of electricity, which is the characteristic of a strong electrolyte. These acids are more likely to donate H* and react with other substances in solution.

However, not every strong electrolyte is a strong acid. A strong electrolyte only indicates that a substance can fully dissociate into ions in solution, enhancing its ability to conduct electricity. Other substances, like strong bases and salts, can also be strong electrolytes. For example, sodium hydroxide (NaOH) is a strong base and a strong electrolyte because it readily dissociates into Na+ and OH- ions in solution.

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Answer:

the answer would be "B"

Explanation:

Elements with the same number of valence electrons are found in the same column of the Periodic Table. All elements in the first column of the Periodic Table have 1 valence electron in an s orbital. These elements are known as Group 1A metals or alkali metals.

All elements within the same group  tend to possess the same number of outer electrons and the correct option is option B.

The periodic table is organized into groups (vertical columns), periods (horizontal rows), and families (groups of elements that are similar). Elements in the same group have the same number of valence electrons.

Meanwhile, elements in the same period have the same number of occupied electron shells.

Elements are typically classified as either a metal or nonmetal.

Metal elements are usually good conductors of electricity and heat. The subgroups within the metals are based on the similar characteristics and  chemical properties of these collections

Therefore, All elements within the same group  tend to possess the same number of outer electrons and the correct option is option B.

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Answer:

3.6m/s

Explanation:

The following data were obtained from the question:

Frequency = 3Hz

Wavelength = 1.2m

Velocity =?

Velocity = wavelength x frequency

Velocity = 1.2 x 3

Velocity = 3.6m/s

Answer:

basic

Explanation:

A solution of copper (I)hydroxide is a base and it will form a basic solution no matter what.

A base is a compound the produces hydroxyl ions in aqueous solutions. Most known bases always have the OH⁻ group attached to them in a compound.

Copper(I) hydroxide is a an alkali as it can dissolve in water. It shares all the unique characteristics of a typical base and it will turn red litmus paper blue.

Answer:

The pH value comes out to be 9.03. We will get an alkaline solution by the hydrolysis of the salt of a weak acid and a strong base.

Explanation:

[tex]KC_{2}H_{3}O_{2}[/tex]  is a salt of a weak acid acetic acid and a strong base KOH. This salt will hydrolyze in water to give an alkaline solution.

Assuming concentration (C) of the salt to be 0.2 M as it is not given.

[tex]K_{a}[/tex] of acetic acid = [tex]1.8\times 10^{-5}[/tex]

[tex]\textrm{pK}_{a} = -\textrm{ log}\left ( K_{a} \right ) \\\textrm{pK}_{a} = -\textrm{ log}\left ( 1.8\times 10^{-5} \right ) \\\textrm{pK}_{a} = 4.75[/tex]

The formula of pH on hydrolysis of salt of weak acid and strong base is given below

[tex]pH = \displaystyle \frac{1}{2}\left ( pK_{w}+pK_{a}+\textrm{log}C \right ) \\pH = \displaystyle \frac{1}{2} \left ( 14+4.75+\textrm{log}0.2 \right ) \\pH = 9.03[/tex]

The pH of solution comes out to be 9.03

To calculate the pH of a KC2H3O2 solution, determine the Kb of the acetate ion using the provided Ka for acetic acid and then calculate the concentration of hydroxide ions to finally find the pH of the solution through the formula pH = -log[H+].

To calculate the pH of a potassium acetate (KC2H3O2) solution, we must first understand the relationship between the acid dissociation constant (Ka) of acetic acid (HC2H3O2) and the base dissociation constant (Kb) of its conjugate base, the acetate ion (C2H3O2-). Using the formula Kw = Ka × Kb, where Kw is the ion-product constant for water (1.0 × 10^-14 at 25°C), we can calculate Kb with the given Ka for acetic acid (1.8 × 10^-5).

First, solve for Kb:

Kb = Kw / Ka

Kb = (1.0 × 10^-14) / (1.8 × 10^-5)

Kb = 5.56 × 10^-10

Knowing the Kb value, we can then use the given concentration of the KC2H3O2 solution to find the hydroxide ion concentration [OH-] and subsequently the hydrogen ion concentration [H+]. The pH is then calculated using the formula pH = -log[H+]. The complete solution would include detailed calculations of [OH-], [H+], and pH, factoring in the initial concentration of the KC2H3O2 solution.

Answer:

1.01atm

Explanation:

760mmHg = 1atm

765mm Hg = 765/760 = 1.01atm

Therefore, the barometer reading in atmosphere is 1.01atm

Answer:

a. 2.7 mol of water

b CH2.

c. O2

Explanation:

The complete equation of the reaction should be:

2CH2(g) + 3O2(g) → 2 CO2(g) + 2 H2O(g)

a) how many moles of water will be  made?

To make 2 molecules of water (H2O) we need 2 molecules of CH and 3 molecules of O2.

We have 2.7 mol of CH2, the possible yield of water produced if it all used up will be:

2.7 mol * 2/2= 2.7 mol

We have 6.3 mol of O2, the possible yield of water produced  if it all used up will be:

6.3 mol * 2/3 = 4.2 mol

Since the maximum yield of CH2 lower, we can have 2.7 mol of water and have some excess oxygen at the end of the reaction.

b) What is the limiting reactant?

A limiting reactant is a reactant that will be used up in the reaction. This reactant has the lowest stoichiometric ratio compared to other reactants, which make them the one depleted out first. Since they depleted, the reaction will stop. Thus they limit the number of reactions and called limiting reactants. If you add the limiting reactant, the reaction will continue.

The limiting reactant in this reaction is the CH2. When producing water molecules, all 2.7 mol of CH2 will be used while we still have O2 left.

c) What is the excess reactant?

The excess reactant will have some remains after the reaction stop. That is because the excess reactant has more mass than needed for the reaction that will use all limiting reactants. Since we still have remains, adding excess reactant won't continue the reaction.

The excess reactant in this question is O2 since it still has remained after we make 2.7 mol of water. The O2 remaining, in this case, will be:

6.3 mol - 2.7mol * 3/2= 2.25 moles

Answer:

1. Nitric Acid

2. Hydrochloric Acid

3. Acetic Acid

4. Hydrogen bromide

5. Nitrous Acid

Explanation:

1. H2SO4

2. HF

3. H3PO4

4. H2CO3

5. H2S

P.S. make the numbers smaller ok?