What is the percent composition of silicon in silicon carbide (SiC)? A. 28% B. 50% C. 70% D. 142%

Answer:

Gas

Explanation:

Nitrogen is an element. It's a gas at room temperature. Nitrogen makes up about 78% of the Earth's atmosphere. Liquid nitrogen is very cold, so it is often used to freeze food.

The transfer of energy by heat flow through a substance is accomplished by convection.

Answer:

The real answer is conduction.

Trust me on this one, it's correct. If you put the other answer, you will get it wrong. The answer is conduction, and I am 100% positive! :)

Answer:

The VSEPR theory stands for the valence shell electron pair repulsion theory. It is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms.

Answer:

It predicts individual molecules from electron pairs surrounding the central atom.

Explanation:

Its A Valence Shell Electron Pair Repulsion Theory.

Hope my answer has helped you!

When reduction occurs, an element gains electrons and its oxidation number decreases or is reduced (becomes more negative). To determine if a redox reaction has occurred and to identify the element oxidized and the element reduced: . Compare oxidation numbers from the reactant side to the product side of the equation.

Answer:

Helium

In the sun, hydrogen is converted to __Helium__ through nuclear fusion.

Answer:

helium

Explanation:

Answer:

Structural

Explanation:

Isomerism is the existence of two or more compounds with the same molecular formula but different molecular structures due to the difference in the arrangement of atoms or spatial orientation of atoms.

Isomers have the same molecular formula but differs in their structural arrangement.

In organic chemistry, Isomerism can orginate from different arrangement of atoms.

It can be carbon chain length known as chain isomerism. Here, the carbon length is changed and arranged in different ways.

We can also have position isomerism which entails the position of the functional group in the structure.

It can also be functional group isomerism which deals with the possible arrangement of the group on the chain.

Isomers have the same molecular formulas but different structural formulas. This different structural arrangement leads to differences in the physical and chemical properties of the isomers.

Isomers are molecules that have the same molecular formula, meaning the same number and type of atoms, but different arrangements of atoms within the molecule. Hence, isomers have different structural formulas, which are used to represent the three-dimensional arrangement of atoms in a molecule. For instance, the compounds butane and isobutane both have the formula C4H10, but in butane, all four carbon atoms are arranged in a row, while in isobutane, three carbon atoms form a branch off a central carbon atom. Therefore, the structural formulas of these compounds differ, even though the molecular formula is the same.

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Answer:

During incomplete combustion of hydrocarbons/carbon carbon monoxide, water and carbon are produced as byproducts instead of CO2. Insufficient combustion usually takes place when the supply of air or oxygen is inadequate.

The general reaction of insufficient combustion:

Hydrocarbon + oxygen → carbon monoxide + carbon + water

In this reaction, carbon is produced as soot. Carbon monoxide is an air pollutant.

Impacts:

1- Incomplete combustion causes suffocation and ultimately death.

2- CO is taken inside the lungs and combines with hemoglobin molecules and reduces the oxygen-carrying capacity of the blood.

the thing that must change Speed

Answer:

The Speed of the object must change in order to keep moving or stop moving so your answer would be A. Only its speed

Explanation:

Answer:

3. a.) BECAUSE the positive protons and negative electrons must balance each other’s charges out

4. a.) BECAUSE the number of protons must stay the same even if the number of neutrons changes (atoms are partially defined by their number of protons)

5. b.) BECAUSE there are 3 atoms (2 hydrogen and 1 oxygen) and 10 electrons shared between them

Answer:

covalent bond  

ionic bond

hydrogen bond

hope this helps enjoy

Explanation:

Final answer:

The elasticity seen in solids is due to the forces between atoms acting like springs that can be stretched or compressed but not easily broken. This allows solids to return to their original shape after the external forces causing deformation are removed.

Explanation:

Elasticity in solids is a result of the atoms in the material being in close contact and vibrating but not changing positions with neighboring atoms. The forces between the atoms act like springs that can be stretched or compressed but not easily broken. This resistance to deformation and ability to return to their original shape is what causes the elasticity seen in solids. For example, when a solid is stretched, the atomic springs are stretched, but when the force is removed, the springs bring the material back to its original shape.

Answer:

The unknown base concentration can be calculated from

Explanation:

An acid–base titration is a quantitative method of analysis for the determination of the concentration of an acid or base by neutralizing it with a standard solution (solution of known concentration) of base or acid.

At the equivalence point, when all unknown  base neutralized by standard acid solution

the following is applied  

No. of equivalent of acid = No. of equivalent of base

Cₐ * Vₐ = Cb * Vb

where,

Cₐ: is the concentration of standard acid solution  (known).

Vₐ: is the volume of acid that neutralizes the base (known).

Cb: is the unknown base concentration (unknown).

Vb: is the volume of base that neutralized with the acid (known).

So, the unknown base concentration can be calculated from

The concentration of base in a titration is calculated using the formula: concentration of base (M) = moles of acid / volume of base (L). This calculation is based on the stoichiometry of the neutralization reaction, typically in a one-to-one mole ratio, and is performed after achieving neutrality as indicated by an indicator or pH meter.

To calculate the concentration of base in a titration, a known volume and concentration of an acid are titrated against the base with an unknown concentration. The formula used for this calculation is concentration of base (M) = moles of acid / volume of base (L). This equation comes from the stoichiometry of the neutralization reaction, which for monoprotic acids and bases is typically a one-to-one mole ratio.

Using the stoichiometry of the neutralization reaction, which in a simple acid-base reaction like HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l), is 1:1, you can determine the moles of base that react with the moles of acid. The moles of acid are calculated by multiplying the concentration of the acid by the volume of acid (in liters). Once neutrality is achieved, indicated by a color change of the indicator or a specific reading on a pH meter, the volume of base used is noted. The moles of acid originally present in the solution are equal to the moles of base since they react in a 1:1 ratio. This allows the calculation of the base concentration using the titrant volume and the known concentration of the acid.

Answer:

carbon monoxide (CO) or nitric oxide (NO),

Explanation:

Answer:

1) a. 2Fe(s) + 3Cl₂(g) → 2FeCl₃(s).

2) a. 0.4477 mol.

b. 0.4477 mol.

c. 72.61 g.

Explanation:

1) Consider the following reaction:  iron (s) + chlorine (g) à iron (III) chloride

a. Write the balanced chemical equation.

So, the balanced chemical equation is:

2Fe(s) + 3Cl₂(g) → 2FeCl₃(s).

It is clear that 2 mol of Fe(s) react with 3 mol of Cl₂(g) to produce 2 mol of FeCl₃(s).

2) 25.0 g of iron reacts with excess chlorine gas.  

a. Calculate the moles of iron reactant.

n = mass/molar mass = (25.0 g)/(55.845 g/mol) = 0.4477 mol.

b. Calculate the moles of iron (III) chloride.

Using cross multiplication:

2 mol of Fe produce → 2 mol of FeCl₃, from stichiometry.

∴ 0.4477 mol of Fe produce → 0.4477 mol of FeCl₃.

∴ The no. of moles of iron (III) chloride produced is 0.4477 mol.

c. Calculate the mass of iron (III) chloride.

mass of  iron (III) chloride = (no. of moles)*(molar mass) = (0.4477 mol)*(162.2 g/mol) = 72.61 g.

The balanced chemical equation for the reaction between iron and chlorine is 2 Fe(s) + 3 Cl2(g) → 2 FeCl3(s). A total of 0.448 moles of iron reacts with excess chlorine to produce 0.448 moles of iron (III) chloride, with a mass of 72.67 g.

The balanced chemical equation for the reaction between iron (s) and chlorine (g) to form iron (III) chloride (FeCl3) is: 2 Fe(s) + 3 Cl2(g) → 2 FeCl3(s).

To calculate the moles of iron reactant, use the molar mass of iron, which is 55.85 g/mol. Moles of iron = mass of iron ÷ molar mass of iron = 25.0 g ÷ 55.85 g/mol = 0.448 moles of iron.

The stoichiometry of the reaction shows that 1 mole of iron reacts with 1.5 moles of chlorine to produce 1 mole of iron (III) chloride. Therefore, the moles of iron (III) chloride produced from 0.448 moles of iron is also 0.448 moles.

To calculate the mass of iron (III) chloride produced, multiply the moles of iron (III) chloride by its molar mass (162.20 g/mol). Mass of iron (III) chloride = moles of iron (III) chloride × molar mass of iron (III) chloride = 0.448 moles × 162.20 g/mol = 72.67 g.

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Answer:

Explanation:

The equation tells you that for every mol of H2 you need 2 mols of Na to get it.

1 H2   /  4 mols H2  = 2  mols Na  /   x    Cross multiply

1*x = 4 * 2

x = 8 mol Na

Answer:

8 moles of sodium will react with water to produce 4.0 mol of  hydrogen in the reaction.

Explanation:

The rule of three or is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them. That is, what is intended with it is to find the fourth term of a proportion knowing the other three. Remember that proportionality is a constant relationship or ratio between different magnitudes.

If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other), the direct rule of three must be applied. To solve a direct rule of three, the following formula must be followed:

a ⇒ b

c ⇒ x

Then

[tex]x=\frac{c*b}{a}[/tex]

In this case you can see that by stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), they react and obtain:

But in this case 4 moles of hydrogen are produced. Then the rule of three applies as follows: If by stoichiometry 2 moles of sodium produce 1 mole of hydrogen, how many moles of sodium are needed to produce 4 moles of hydrogen?

[tex]moles of sodium=\frac{4molesofhydrogen*2molesofsodium}{1mole of hydrogen}[/tex]

moles of sodium=8

Then, 8 moles of sodium will react with water to produce 4.0 mol of  hydrogen in the reaction.

Answer:

C₃H₈₍g₎ + 5O₂₍g₎→  3CO₂₍g₎ + 4H₂O₍l₎

Explanation:

Propane is an alkane that burns in enough oxygen to produce carbon (iv) Oxide and heat as the only by products. Balancing the equation: The number of atoms of each kind on either side should be equal. Hydrogen on the left has eight atoms same as the right side after balancing, oxygen has 10 while carbon has 3 on each side.

Answer:The value of the coefficients are:

[tex]a_o=1,a_1=5,a_2=3,a_3=4[/tex]

Explanation:

Number written in front of the molecule or element in balanced chemical reaction is known as stoichiometric coefficient.

[tex]a_oC_3H_8 +a_1O_2 \rightarrow a_2CO2 +a_3H2O[/tex]

The balance chemical reaction will be given by:

[tex]1C_3H_8 + 5O_2 \rightarrow 3CO2 + 4H2O[/tex]

[tex]a_o=1,a_1=5,a_2=3,a_3=4[/tex]

1 mole of octane reacts with 5 moles of oxygen gas to gives 3 moles of carbon dioxide and 4 moles of water as a product.

The conversion of kinetic energy to potential energy is neither exothermic nor endothermic, as it involves the transformation of energy forms within a system, not heat transfer to or from the environment. Option D is correct.

The conversion of kinetic energy to potential energy does not involve heat transfer but rather the transformation of one form of mechanical energy to another within a system. An exothermic process is one in which energy is released to the surroundings, usually in the form of heat, such as when a solid burns brightly, while an endothermic process absorbs energy from the surroundings.

For example, when two chemicals are mixed and their temperature drops, it is considered endothermic because the chemical system absorbed heat from the surroundings.

Hence, D. is the correct option.

Answer:

The answer is 1-butene

Explanation:

Answer:

Electronegativity increases and metallic

properties decrease.

Explanation:

The statement which describes the general trends in electronegativity and metallic properties as the elements in Period 2 are considered in order of increasing atomic number are;

For electronegativity:

For metallic properties:

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Answer:

B. Cementation

Explanation:

The processes by which sediments are changed into rock are complex, but can be simplified into two processes, called compaction and cementation. Rounded sediment grains (ooliths) bound together with crystalline calcite.

Answer:

The correct answer is option B, that is, cementation.

Explanation:

The procedures by which the sediments are modified into rocks are composite, however, can be simplified into two procedures, known as cementation and compaction. In geology, cementation refers to welding and hardening of clastic sediments, that is, those produced from the preexisting fragments of rocks due to the precipitation of the mineral matter in the pore gaps. It is the ultimate phase in the production of sedimentary rock.

Answer:

The red liquid in a thermometer tells you what temperature the thermometer has. So when you dip that thermometer in a warm substance, the red liquid (generally mercury) rises because the warmth makes the liquid expand or jump. The vice versa occurs with a cold substance. That's why you see the liquid going down when you put the thermometer on an ice cube.

Explanation:

Final answer:

A thermometer measures temperature by relying on the thermal expansion and contraction of a substance such as mercury or alcohol within a reservoir. The liquid's volume changes are visible along a graduated scale, providing a temperature reading. Material properties like specific heat and thermal conductivity are critical in thermometer design for performance and accuracy.

Explanation:

A thermometer operates on the principle of thermal expansion, which is the tendency of a substance to change in volume in response to a change in temperature. When a substance is heated, its particles move more vigorously, causing it to expand. Conversely, when the substance is cooled, the particles lose energy and move less, leading to contraction. This behavior is harnessed in a thermometer.

In the case of a mercury or alcohol thermometer, the liquid inside the reservoir expands as it is heated and contracts when it cools. This causes the visible level of the liquid to rise or fall along a calibrated scale, corresponding to the temperature. It's important that the material used for this liquid has uniform thermal expansion properties over the temperature range of interest. This ensures that the thermometer provides a reliable measurement of temperature changes.

When designing a thermometer, aspects such as specific heat and thermal conductivity must be considered. A material with high specific heat requires more energy to change its temperature, which can slow down the response time of the thermometer. On the other hand, thermal conductivity impacts how quickly the material reaches thermal equilibrium with its surroundings, which affects the speed of the reading as well.

Nocturnal animals that burrow underground during the day and are active at night are found in the desert biome.

The biome that has many nocturnal animals that burrow underground during the day and are active at night is the desert biome. In the desert, animals like rodents, reptiles (such as lizards and snakes), and insects have adapted to the extreme temperatures by being active during the cooler nights and seeking shelter from the sun during the day. Examples of nocturnal animals in the desert biome include kangaroo rats, fennec foxes, and scorpions.

Final answer:

The desert biome is characterized by nocturnal animals that burrow during the day to avoid heat and are active at night when temperatures drop.

Explanation:

The biome that you're referring to, where many nocturnal animals burrow underground during the day and are active at night, is likely the desert biome. Nocturnal animals, such as bats, foxes, and coyotes, are active at night partly because the temperature is cooler and more manageable, which is particularly important in the hot desert environment. These animals have adapted to their warm habitats by being active during the cooler nocturnal hours to conserve water and energy. Additionally, nocturnality may help them avoid predators and take advantage of the nighttime ecology, such as different prey species that are also active at night.

Answer:

Heating this gas to 55 °C will raise its volume to 6.87 liters.

Assumption: this gas is ideal.

Explanation:

By Charles's Law, under constant pressure the volume [tex]V[/tex] of an ideal gas is proportional to its absolute temperature [tex]T[/tex] (the one in degrees Kelvins.)

Alternatively, consider the ideal gas law:

[tex]\displaystyle V = \frac{n \cdot R}{P}\cdot T[/tex].

Therefore the volume of the gas is proportional to its absolute temperature.

Either way,

[tex]V\propto T[/tex].

[tex]\displaystyle V_2 = V_1\cdot \frac{T_2}{T_1}[/tex].

For the gas in this question:

Convert the two temperatures to degrees Kelvins:

Apply Charles's Law:

[tex]\displaystyle V_2 = V_1\cdot \frac{T_2}{T_1} = \rm 6.24\;L \times \frac{328.15\; K}{298.15\;K} = 6.87\;L[/tex].

The correct option is b. 6.87 L.

To solve this problem, we can use Charles's Law, which states that the volume of a gas is directly proportional to its temperature in Kelvin at constant pressure. Mathematically, this can be expressed as:

 [tex]\[ \frac{V_1}{T_1} = \frac{V_2}{T_2} \][/tex]

 where [tex]\( V_1 \) and \( T_1 \)[/tex] are the initial volume and temperature of the gas, respectively, and [tex]\( V_2 \) and \( T_2 \)[/tex] are the final volume and temperature of the gas, respectively.

First, we need to convert the temperatures from Celsius to Kelvin:

[tex]\[ T_1 = 25.0^\circ C + 273.15 = 298.15 \text{ K} \][/tex]

[tex]\[ T_2 = 55.0^\circ C + 273.15 = 328.15 \text{ K} \][/tex]

Now we can rearrange Charles's Law to solve for the final volume [tex]\( V_2 \):[/tex]

[tex]\[ V_2 = V_1 \times \frac{T_2}{T_1} \][/tex]

 Substituting the given values:

[tex]\[ V_2 = 6.24 \text{ L} \times \frac{328.15 \text{ K}}{298.15 \text{ K}} \][/tex]

[tex]\[ V_2 = 6.24 \text{ L} \times \frac{328.15}{298.15} \][/tex]

[tex]\[ V_2 = 6.24 \text{ L} \times 1.1007 \][/tex]

[tex]\[ V_2 \approx 6.87 \text{ L} \][/tex]

 Therefore, the new volume of the gas after the temperature increase is approximately 6.87 L.

Answer:

5.75 g.

Explanation:

∴ 46 g →(first half-life) 23 g →(second half-life) 11.5 g →(third half-life) 5.75 g.

Answer:

We use the general gas law or the combined gas law to solve this kind of problem

Explanation:

The general gas law is a combination of both Boyle's law and Charle's law. It is expressed as:

                      [tex]\frac{ P₁V₁}{T₁}[/tex] =  [tex]\frac{ P₂V₂}{T₂}[/tex]

The unkown is V₂ which can be derived by substituting in the equation above.

The general gas law assumes that, n, the number of mole is 1

Answer:  To determine the final Volumen of the gas we use the Combined gas law

Explanation:

The combined gas law combines three gas laws: Boyle's Law, Charles' Law, and Gay-Lussac's Law, this law links pressure, volume, and temperature of a giving gas, from initial conditions ( expressed with the number 1) to final conditions (expressed with the number 2)

P1V1 / T1 = P2V2 / T2

P1 = 745 mm Hg

V1 = 1,56 L

T1 = 27°C + 273,17K = 300.15 K

P2 = 700 mm Hg

V2 = x (the unknown you're solving for)

T2 = 100°C + 273,15K = 373.15 K

V2 = (P1 V1 T2) / (P2 T1)

V2= (745 mm Hg  .  1,56 L . 373.15 K) / ( 700 mm Hg  . 300.15 K )

V2 =  2,06 L

Answer:

1.633L

Explanation:

P1 = 16.24psi

V1 = 0.700L

P2 = 6.961psi

V2 = ?

Using Boyle's law, P1V1 = P2V2

V2 = P1V1/P2

V2 = 16.24*0.7/6.961

V2 = 1.633L

Answer:

CO2 is a compound of carbon and oxygen.

Answer:

CO2

Explanation:

A compound is a  substance  that consists molecules that are formed by atoms from different elements that are bond together. According to this, from the options given, the compound is CO2.

The other options are not right because they only have one element.

When temperature increases pressure also increases.

When temperature decreases pressure decreases.

That is why you have low tire pressure when it’s cold out

Temperature and Pressure have a direct relationship!

When Temperature increases ↑

Pressure increases ↑

When Temperature decreases ↓

Pressure decreases ↓

Nitric acid does NOT react with water, water disassociates the molecules into those ions (above). ... Water,Being a polar solvent,…makes HNO3 ionise or dissociate or simply break down into Hydronium ions, i.e,H+ or H3O+ ions and nitrate NO3- ions..that's all.

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HNO3, or nitric acid, when placed in water, ionizes completely, producing hydronium ions (H3O+) and nitrate ions (NO3-). It can also engage in neutralization reactions with bases to form water and a salt.

When nitric acid (HNO3) is placed in a water solution, it ionizes completely to produce hydronium ions (H3O+) and nitrate ions (NO3-). In this reaction, nitric acid acts as a strong acid. This can be represented by the following equation: HNO3 + H2O → H3O+ + NO3-.

Nitric acid can also react with other substances in water. For example, when HNO3 reacts with a base like Ba(OH)2, a neutralization reaction occurs to form water and a salt (Ba(NO3)2): Ba(OH)2 (aq) + 2HNO3(aq) → Ba(NO3)2(aq) + 2H2O(l).

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Answer:

Intensive properties can be used to help identify a sample because these characteristics do not depend on the amount of sample, nor do they change according to conditions.

Explanation:

Intensive properties are bulk properties, which means they do not depend on the amount of matter that is present. Examples of intensive properties include:

Boiling Point

Density

State of Matter

Color

Melting Point

Odor

Temperature

Refractive Index

Luster

Hardness

Ductility

Malleability

Explanation:

When amount of matter changes in a substance then a physical property that does not change due to this is known as an intensive property.

For example, density, color, boiling point, hardness etc are all intensive properties.

Whereas  property of a substance that changes due to change in amount of matter of a substance is known as extensive property.

For example, temperature, volume etc are all extensive properties.

Hence, we can conclude that given properties are classifies as follows.

Intensive property : color, hardness, boiling point, density, temperature.

Extensive property : length, volume, mass.

Answer:

Explanation:

In a chemical formula, the oxidation state of transition metals can be determined by establishing the relationships between the electrons gained and that which is lost by an atom.

We know that for compounds to be formed, atoms would either lose, gain or share electrons between one another.

The oxidation state is usually expressed using the oxidation number and it is a formal charge assigned to an atom which is present in a molecule or ion.

To ascertain the oxidation state, we have to comply with some rules:

For example, let us find the oxidation state of Cr in Cr₂O₇²⁻

This would be:  2x + 7(-2) = -2

                          x = +6

We see that the oxidation number of Cr, a transition metal in the given ion is +6.

Answer: it's total charge of something I already forgot

Explanation: finished quiz don't listen to Einstein above me why do u think he got little votes and likes