Compared to the Apollo program, the Space Shuttle has been

A. a complete failure.

B. much more successful.

C. considered a mixed success.

D. able to explore much more of the solar system.

Answer:

add up the mass of protons and neutrons

Explanation:

Answer:

Explanation:

The mass number is a specific property of the atoms, defined as the sum of the protons and neutrons, which are the subatomic particles that are in the nucleus of the atom.

The electrons do not count for the mass of atoms because their mass is about 1/1840 the mass of a proton or a neutron.

The relative masses of protons and neutrons is 1: 1, then they count equally.

As an example, the mass number of the atom carbon-12 is calculated in this way:

The number 12 added to the name in carbon-12, stands for its mass number.

Also, the mass number is indicated as a superscript to the left of the chemical symbol of the element, and the atomic number as a subscript to the left of the chemical symbol. For the example of carbon-12 that is:

Answer:

2. 110.

Explanation:

From the solubility curve, you can find that at 45°C to make a saturated solution of this salt, you should add 110 g of NaNO₃.

The dissolution of  the solute in the solvent at the specified temperature is termed as solubility. The maximum solubility of sodium nitrate in the water at 45 degree Celsius in 110 grams.

The increase in temperature of the solvent resulted in the weaker the intermolecular force of solvent, and increases the solubility.

The solubility curve is drawn for the maximum amount of solute that can be dissolved in the solvent at the specified temperature.

From the solubility curve of sodium nitrate, the maximum amount of sodium nitrate in the water at 45 degree Celsius is 110 grams. Thus, option 2 is correct.

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Answer:

Pastoral farming is best described as a method of raising livestock and moving herds. (a.)

In order to provide the 300 moles of sodium nitrite required for the reaction using a 0.450 m solution, you would need 666,667 mL of the solution.

To determine how many milliliters of a 0.450 m sodium nitrite solution are needed for a reaction where 300 moles of sodium nitrite are needed, you'll want to use the equation that relates moles, molarity (M), and volume (V). This equation is Moles = Molarity x Volume.

For the given question, we know the amount of moles (300 moles) and the molarity (0.450 m), so we can rearrange the equation and plug in our values to find the volume: Volume (L) = Moles / Molarity = 300 moles / 0.450 M = 666.67 L.

Do remember to convert this volume to milliliters because the question asks for the answer in milliliters. 666.67 L x 1000 mL/L= 666,667 mL.

Therefore, you would need 666,667 mL of a 0.450 m sodium nitrite solution to provide the 300 moles of sodium nitrite required for the reaction.

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To determine the volume of solution needed for the reaction, we can use the formula Volume = Number of moles / Molarity. In this case, the volume of solution needed is approximately 666,666.67 mL.

To determine the volume of solution needed, we need to first calculate the number of moles of sodium nitrite in 300 moles. Since the solution is 0.450 M, this means there are 0.450 moles of sodium nitrite in every 1 liter of solution. Therefore, to calculate the volume of solution needed, we can use the formula:

Volume (in liters) = Number of moles / Molarity

Volume = 300 moles / 0.450 moles

To convert the volume from liters to milliliters, we can multiply the volume by 1000:

Volume (in milliliters) = Volume (in liters) * 1000

Plugging in the values, we get:

Volume (in milliliters) = (300 moles / 0.450 moles) * 1000 = 666666.67 mL

Therefore, approximately 666,666.67 mL of solution are needed for the reaction.

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Answer:

Ethanoic acid and 1-butanol can react to produce water and a compound classified as an ester.

Explanation:

Ethanoic acid reacts with ethanol in the presence of concentrated sulphuric acid as a catalyst to produce the ester "butyl ethanoate" and water:

CH₃COOH + CH₃CH₂CH₂CH₂OH → CH₃COOCH₂CH₂CH₂CH₃.

Ethanoic acid reacts with 1-butanol in an esterification reaction to produce butyl ethanoate and water. This is a common type of reaction in organic chemistry, resulting in the formation of an ester.

When ethanoic acid reacts with 1-butanol, a type of chemical reaction called esterification occurs. Esterification typically involves the reaction of a carboxylic acid (in this case, ethanoic acid) with an alcohol (here, 1-butanol) to form an ester and water. The specific ester formed from ethanoic acid and 1-butanol is called butyl ethanoate, and this is the compound classified as an ester mentioned in the question. The reaction can be summarized by the following equation:

CH₃COOH (ethanoic acid) + C₄H₉OH (1-butanol) →CH₃COOC₄H₉(butyl ethanoate) + H₂O (water)

This reaction typically requires an acid catalyst to proceed, commonly sulfuric acid or hydrochloric acid. The process of creating esters like butyl ethanoate is important in both organic chemistry and industry, where esters are used as fragrances, flavors, and solvents.

Answer:

Explanation:

A substance that produces an excess of hydroxide ion (-OH) in aqueous solution.

       This is an arrhenius Base

According to the arrhenius theory, a base is a substance that combines with water to produce excess hydroxide ions, OH⁻ in an aqeous solution. Examples are :

A substance that produces an excess of hydrogen ion (H+) in aqueous solution

      This is an arrhenius Acid

An arrhenius acid is a substance that reacts with water to produce excess hydrogen ions in aqueous solutions.

Examples are;

To find the volume of seawater containing 7.5 g of sodium, one must first convert this mass to the equivalent mass of NaCl, then calculate the total mass of seawater needed, and finally use the density of seawater to find the corresponding volume.

The question asks to calculate the volume of seawater that contains 7.5 g of sodium. First, we need to determine the mass of NaCl which corresponds to 7.5 g of sodium. Given that the atomic weight of sodium (Na) is approximately 23 g/mol, we can find the amount of NaCl using the ratio of the molecular weight of NaCl (58.44 g/mol) to that of Na. Once we have this mass, we can use the percentage of NaCl in seawater (3.5%) to find the total mass of seawater needed. Finally, given the density of seawater (1.02 g/mL), we can calculate the volume of seawater containing this total mass.

Final answer:

To calculate the volume of seawater that contains 7.5g of sodium, we use the concentration of NaCl in seawater and the atomic masses of Na and Cl. We find that approximately 529.00mL of seawater is needed to provide 7.5g of sodium.

Explanation:

To determine the volume of seawater containing 7.5 g of sodium, we must first understand the concentration of NaCl in seawater and the atomic mass of sodium. Seawater contains approximately 3.5% NaCl by mass. Given that the atomic masses of Na and Cl are 23.0 and 35.4 respectively, we can calculate the mass of sodium in seawater. Using the percentage by mass and the given density of seawater, we can then calculate the volume.

The mass percentage of NaCl in seawater is 3.5%, which means in 100g of seawater, there is 3.5g of NaCl. To find the mass of sodium only, we consider the molar mass ratio of Na to NaCl, which is 23.0 / (23.0 + 35.4). Therefore, the mass of sodium in 3.5g of NaCl is given by:
(23.0 / 58.4) × 3.5g.

To find the mass of Na in 100g of seawater, we multiply this by the mass percentage of NaCl in seawater:
(23.0 / 58.4) × 3.5g × 1.00 = 1.39g (rounded to two decimal places).

Thus, to find the amount of seawater containing 7.5g of Na, we would do the following calculation:
(100g seawater / 1.39g Na) × 7.5g Na= 539.57g of seawater.

Finally, to convert this mass to volume using the density of seawater (1.02g/mL), the volume is:
539.57g / 1.02g/mL = 529.00mL (rounded to two decimal places).

Therefore, approximately 529.00mL of seawater contains 7.5g of sodium.

Answer:

Chemical change is basiclly chemical reaction that creates new substances, sometimes can be hard to observed. The melting of the ice only involves in changing the form of the matter, from solid to liquid form, it doesn't transform the substance which is water into another substance. Therefore, the melting of ice is not a chemical change, but rather a physical one.

Answer:

A new substance is not formed

Explanation:

Its still water just not physically

Answer:

A. True

Explanation:

You are right, the answer is a. true!

distillation, magnetic attraction, filtration

Answer:

True

Explanation:

0°C = 273°k

0°C = 273°k ....

It is true.

Answer:

The volume of the gas is directly proportional and amount (moles) of the gas at constant T and P.

Explanation:

Answer:

Fluorine

Explanation:

Flourine forms an ionic bond when combined with lithium. The valence electronic shell of lithium has just one single electron. Fluorine has 7 electrons in its valence shell but requires just a single electron to complete its octet. When lithium and fluorine combines, fluorine achieves its octet and lithium resembles Helium, a noble gas. This transfer of electron between Li and F is what results in an ionic bond between the two elements. It is also worthy to note that for an ionic bond to form, the electronegative difference between the two atoms should be greater than 0.7.

Fluorine has an electronegativity of 4.0 and that of Li is 1.0. The difference is 3.0. This implies that an ionic compound would be formed. The compound is LiF, Lithium Fluoride.

Answer:

Metal A has the highest density.

Explanation:

Density is defined as mass present in unit volume of the substance.

[tex]Density=\frac{Mass}{Volume}[/tex]

Density of metal A

Mass of metal = 122 g

Volume of metal = [tex]10.5 cm^3[/tex]

[tex]D=\frac{122 g}{10.5 cm^3}=11.61 g/cm^3[/tex]

Density of metal B

Mass of metal = 132 g

Volume of metal = [tex]14.2 cm^3[/tex]

[tex]D=\frac{132 g}{14.2 cm^3}=9.29 g/cm^3[/tex]

Density of metal C

Mass of metal = 115 g

Volume of metal = [tex]16.1 cm^3[/tex]

[tex]D=\frac{115 g}{16.1 cm^3}=7.14 g/cm^3[/tex]

Density of metal D

Mass of metal = 126 g

Volume of metal = [tex]12.7 cm^3[/tex]

[tex]D=\frac{126 g}{12.7 cm^3}=9.92 g/cm^3[/tex]

Metal A has the highest density.

Answer:

See below.

Explanation:

CH4 + 2 O2 → CO2 + 2H2O

One molecule of methane reacts with 2 molecules of oxygen to produce one molecule of carbon dioxide and two molecules of water.

It is also true if we replace the word molecule by mole.

Answer : The correct option is,

One molecule of methane reacts with two molecules of oxygen to produce one molecule of carbon dioxide and two molecules of water.

One mole of methane reacts with two moles of oxygen to produce one mole of carbon dioxide and 2 moles of water.

Explanation :

The given balanced chemical reaction is,

[tex]CH_4+2O_2\rightarrow CO_2+2H_2O[/tex]

Balanced chemical reaction : It is defined as the reaction in which the number of atoms of individual elements present on reactant side must be equal to the product side.

The given chemical reaction is a balanced reaction.

By the stoichiometry we can say that,

One molecule of methane reacts with two molecules of oxygen to produce one molecule of carbon dioxide and two molecules of water.

or,

One mole of methane reacts with two moles of oxygen to produce one mole of carbon dioxide and 2 moles of water.

Answer:

Molar mass

Explanation:

This is a counting unit which represents the mass in grams of a substance that make up one mole of the substance. This mass is calculated as follows:

Molar mass = Mass/ Number of moles

Units: grams/mol

Molar mass is also known as number of grams/mole of something.

A substance's molar mass is defined as substance mass divided by the substance amount in moles. It is expressed in Kg/mol but gram/mol is used for the convenience for study.

It is often used in chemistry for the conversion of mass in grams to substance moles. The relation that is used to convert the gram top mole is that the molar mass is equal to the molecular mass in grams.

Answer:

b. CH3OCH3, amine.

Explanation:

It is not an amine It is ethyl ether.

The option that is incorrect pairing is b. CH3OCH3, amine.

CH3OCH3 represents the chemical formula for dimethyl ether, which is a type of ether. Ethers are organic compounds characterized by an oxygen atom linking two alkyl or aryl groups. They are not classified as amines.

Amines, on the other hand, are a different class of organic compounds that contain a nitrogen atom bonded to carbon atoms. They are typically named with the suffix "-amine" and can be primary, secondary, or tertiary depending on the number of alkyl or aryl groups bonded to the nitrogen atom.

Therefore, the pairing of CH3OCH3 with amine is incorrect, as CH3OCH3 is an ether, not an amine.

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Answer:

K₂CO₃    

Explanation:

Given parameters:

Number of moles of K = 0.104mol

Number of moles of C = 0.052mol

Number of moles of O = 0.156mol

Method

From the given parameters, to calculate the empirical formula of the elements K, C and O, we reduce the given moles to the simplest fraction.

Empirical formula is the simplest formula of a compound and it differs from the molecular formula which is the actual formula of a compound.

Solution

Elements                             K                       C                    O

Number of moles            0.104                0.052            0.156

Dividing by the

smallest                       0.104/0.052     0.052/0.052  0.156/0.052

                                            2                           1                     3

The empirical formula is K₂CO₃      

The empirical formula of a compound containing 0.104 mol of potassium (K), 0.052 mol of carbon (C), and 0.156 mol of oxygen (O) is K2CO3, based on the smallest whole number ratio of moles of each element.

To determine the empirical formula of a compound from the amount of moles of each element, you need to find the smallest whole number ratio of the moles of each element. For the compound mentioned with 0.104 mol K (potassium), 0.052 mol C (carbon), and 0.156 mol O (oxygen), you can do this by dividing each mole value by the smallest of the amounts of moles present.

In this case, the smallest value is 0.052 mol (carbon). So you would divide the number of moles of each element by 0.052 mol:

Therefore, the empirical formula is K2CO3.

Answer:

In a primary cell, two electrodes (one of copper and other of zinc) of metal atoms are used. These electrodes are dipped in an electrolyte solution that causes the metals to produce their respective positive and negative ions.

In this way, the flow of charges takes place and supply the electricity to the source.

Unlike a primary cell, a dry cell contains paste of an electrolyte instead of the solution. The contents of electrolyte paste react with each other through a chemical process and convert the chemical energy into electrical energy.

Answer:

In primary cells, an electric potential develops through chemical action between the plates within the cell. Positively charged ions of zinc enter the acid and free electrons released from zinc atoms collect on the zinc plate, which results in a negative charge. At the same time, positively charged ions of hydrogen from the acid remove free electrons from the copper plate, which becomes positively charged. Through a conducting material connecting the plates, free electrons move from the zinc plate to the copper plate as long as the chemical reaction lasts.

Dry cells also develop electric potential via chemical actions within the cell. Free electrons removed from the carbon rod collect on a zinc can. The rod exhibits a positive charge and the can becomes negatively charged; this allows for an electric potential to develop between these two items. Through a conducting material connecting the can to the rod, free electrons move from the can to the rod as long as the conducting path exists.

Explanation:

straight from Penn

Answer:

Explanation:

1) Chemical formula of sodium carbonate: Na₂CO₃

2) Ratio of carbon atoms:

Hence, the ratio is 1 C atom / 1 Na₂CO₃ unit formula.

This is, there is 1 atom of carbon per each unit formula of sodium carbonate.

3) Calculate the number of moles in 1.773 × 10⁷ carbon atoms

Since, the ratio is 1: 1, the number of moles of sodium carbonate is the same number of moles of carbon atoms.

Answer: D) Light is made up of photons

Light, Einstein said, is a beam of particles whose energies are related to their frequencies according to Planck's formula. When that beam is directed at a metal, the photons collide with the atoms. If a photon's frequency is sufficient to knock off an electron, the collision produces the photoelectric effect.

Option D, Light is made up of photons.

The photoelectric effect is a phenomenon where electrons are emitted from the metal surface when the light of sufficient frequency is incident upon. The concept of the photoelectric effect was first documented in 1887 by Heinrich Hertz and later by Lenard in 1902. But both the observations of the photoelectric effect could not be explained by Maxwell’s electromagnetic wave theory of light.

Light, Einstein said, is a beam of particles whose energies are related to their frequencies according to Planck's formula. When that beam is directed at a metal, the photons collide with the atoms. If a photon's frequency is sufficient to knock off an electron, the collision produces the photoelectric effect.

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Answer:

Oxidation state of N in (NH₄) is (-3).

Oxidation state of N in (NO₂) is (+3).

Explanation:

NH₄NO₂ → NH₄⁺ + NO₂⁻.

NH₄⁺:

The total oxidation state of NH₄⁺ is (+1).

The oxidation state of H is known to be (+1).

∴ Oxidation state of N + 4(oxidation state of H) = +1.

∴ Oxidation state of N + 4(+1) = +1.

∴ Oxidation state of N = +1 - 4 = -3.

NO₂⁻:

The total oxidation state of NO₂⁻ is (-1).

The oxidation state of O is known to be (-2).

∴ Oxidation state of N + 2(oxidation state of O) = -1.

∴ Oxidation state of N + 2(-2) = -1.

∴ Oxidation state of N - 4 = -1.

∴ Oxidation state of N = -1 + 4 = +3.

Two oxidation states of nitrogen in NH₄NO₂ is +3 & -3.

Oxidation state of any atom tells about the no. of electrons gain or looses from that atom.

NH₄NO₂ is dissociates as:

NH₄NO₂ → NH₄⁺ + NO₂⁻

Oxygen state of nitrogen in NH₄⁺ can be calculated as:

x + 4(1) = 1

x = 1 - 4 = -3

In NH₄⁺, oxidation state of hydrogen is +1 & whole charge on the ion is also +1.

Oxygen state of nitrogen in NO₂⁻ can be calculated as:

x + 2(-2) = -1

x = -1 + 4 = 3

In NO₂⁻, oxidation state of oxygen is -2 & whole charge on the ion is -1.

Hence, -3 & +3 are the oxidation states of nitrogen.

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Answer:

Compound B.

Explanation:

The freezing point depression is a colligative property. It depends on the number of particles (moles) present in the solution.

[tex]\Delta T_{\text{f}} = K_{\text{f}} b[/tex]

where b is the molal concentration

[tex]b = \dfrac{\text{moles of solute}}{\text{kilograms of solvent}}\\\\n = \dfrac{\text{mass}}{\text{molar mass}} = \dfrac{m}{M}[/tex]

If m is constant (5 g), then

[tex]n \propto \dfrac{1}{M}[/tex]

The compound with the greater molar mass has fewer moles and therefore fewer particles to depress the freezing point.

That must be Compound B, because Compound A has the lower freezing point.

Solute compound A caused a greater freezing point depression than compound B, suggesting that compound A has fewer particles in solution. Therefore, compound A must have the greater molar mass compared to compound B.

The question pertains to the concept of colligative properties, particularly, freezing point depression. Compound A, when dissolved in water, caused the freezing point to decrease more than compound B did under the same conditions. This behavior is explained by the colligative property of freezing point depression, which states that the freezing point of a solvent will decrease when a solute is dissolved in it.

The amount of freezing point depression is directly related to the number of solute particles in solution. Because both solutions contain the same mass of solute but compound A caused a larger freezing point depression, it must be that compound A has fewer particles in solution compared to compound B. Since fewer particles correspond to a larger molar mass, compound A has the greater molar mass.

Answer:

The statement is false

Explanation:

Interstellar clouds are not primarily composed of nitrogen and oxygen. Interstellar clouds are generally an made up of gas, plasma, and dust in our and other galaxies.

Answer: False

Explanation:

An interstellar cloud can be defined as the accumulation of gas, plasma and dust in our galaxy or other galaxy.

The composition of interstellar clouds are determined by studying the electromagnetic radiation that is received by radio waves, gamma rays on the electromagnetic spectrum.

When The electromagnetic radiations was studied then organic compounds like vinyl chloride and methanol which was not expected.

Answer:

they are transfer from the  towers

Explanation:

Answer:

4.50 liters

Explanation:

Boyles law P1 · V1 =P2 · v2

V2=P1·V1÷P2

V2= 3 · 1.5 ÷ 1

Answer:

(4) 2.0 M CaCl₂(aq).

Explanation:

ΔTb = i.Kb.m,

where, ΔTb is the elevation in boiling point.

i is the van 't Hoff factor.

Kb is the molal elevation constant of water.

m is the molality of the solution.

(1) 1.0 M KCl(aq):

i for KCl = no. of particles produced when the substance is dissolved/no. of original particle = 2/1 = 2.

suppose molarity = molality, m = 1.0 m,

∴ ΔTb for (1.0 M KCl) = i.Kb.m = (2)(Kb)(1.0 m) = 2(Kb).

(2) 2.0 M KCl(aq):

i for KCl = no. of particles produced when the substance is dissolved/no. of original particle = 2/1 = 2.

suppose molarity = molality, m = 2.0 m,

∴ ΔTb for (1.0 M KCl) = i.Kb.m = (2)(Kb)(2.0 m) = 4(Kb).

(3) 1.0 M CaCl₂(aq):

i for CaCl₂ = no. of particles produced when the substance is dissolved/no. of original particle = 3/1 = 3.

suppose molarity = molality, m = 1.0 m,

∴ ΔTb for (1.0 M KCl) = i.Kb.m = (3)(Kb)(1.0 m) = 3(Kb).

(4) 2.0 M CaCl₂(aq):

i for CaCl₂ = no. of particles produced when the substance is dissolved/no. of original particle = 3/1 = 3.

suppose molarity = molality, m = 2.0 m,

∴ ΔTb for (1.0 M KCl) = i.Kb.m = (3)(Kb)(2.0 m) = 6(Kb).

The aqueous solution with the highest boiling point at standard pressure is the 2.0 M CaCl2 solution because it has the highest concentration and dissociates into the most ions.

The boiling point of an aqueous solution is influenced by the concentration of solutes due to the colligative property known as boiling point elevation. According to the principle of boiling point elevation, each mole of solute particles will raise the boiling point of 1 liter of water by 0.51°C. Taking this into account, the boiling point of a solution is also affected by the number of particles into which each formula unit dissociates in solution. For example, CaCl2 dissociates into three ions (one calcium ion and two chloride ions).

Given the options, the aqueous solution with the highest boiling point at standard pressure is the 2.0 M CaCl2 solution (Option 4). This is because it has the highest concentration of particles in solution: for every mole of CaCl2 there are three moles of ions due to dissociation, and its molarity is the highest among the given solutions.

Answer:

Lithium bromide, or LiBr, is the name of the iconic compound formed from lithium and bromine.

The ionic compound formed from lithium and bromine is called Lithium Bromide.

Lithium Bromide has the chemical formula LiBr. Lithium is a metal that belongs to the alkali metal group, while bromine is a non-metal that belongs to the halogen group.

When lithium and bromine react, they form an ionic compound, in which lithium donates an electron to bromine. Lithium becomes a positively charged ion, called a lithium ion, while bromine becomes a negatively charged ion, called a bromide ion.

The lithium ions and the bromide ions are then attracted to each other by the force of electrostatic attraction.

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Answer:

Twice  as much.

Explanation:

That's because the freezing point depression depends on the total number of solute particles.

C₆H₁₂O₆(s) ⟶ C₆H₁₂O₆(aq)

0.01 mol of C₆H₁₂O₆ gives 0.01 mol of solute particles.

NaCl(s) ⟶ Na⁺(aq) + Cl⁻(aq)

1 mol of NaCl gives 0.01 mol of Na⁺(aq) and 0.01 mol of Cl⁻(aq).

That's 0.02 mol of particles, so the freezing point depression of 0.01 mol·L⁻¹ NaCl will be twice that of 0.01 mol·L⁻¹ C₆H₁₂O₆.