11th grade chemistry study guide need help

For a solution with a pH of 4, the hydroxide ion concentration [OH-] is calculated by subtracting the pH from 14 to get the pOH, and then finding 10^-pOH, resulting in [OH-] = 1 x 10⁻¹⁰ M.

So, the correct answer is option 1) 1 x 10⁻¹⁰.

The question resolves around finding the hydroxide ion concentration ([OH-]) in a solution with a specific pH. To calculate the [OH-] for a solution with a pH of 4, we use the relationship where the sum of the pH and pOH equals 14. First, we find the pOH by subtracting the given pH from 14:

pOH = 14 - pH = 14 - 4 = 10.

Then, we use the pOH to determine the hydroxide ion concentration:

The [OH-] in a solution with a pH of 4 is therefore 1 x 10⁻¹⁰ M.

So, the correct answer is option 1) 1 x 10⁻¹⁰.

a.uses of functional groups involving oxygen

Answer : The correct option is, (A) uses of functional groups involving oxygen.

Explanation :

(1) [tex]R-OH[/tex] : It belongs to an alcoholic functional group in which the the [tex]-OH[/tex] group is directly attached to the alkyl group of carbon.

(2) [tex]R-O-R^'[/tex] : It belongs to an ether functional group in which the the oxygen is directly attached to the two alkyl group of carbon.

(3) [tex]R-CO-R^'[/tex] : It belongs to ketone functional group in which the the [tex]-CO[/tex] group is directly attached to the two alkyl group of carbon.

(4) [tex]R-CHO[/tex] : It belongs to an aldehyde functional group in which the the [tex]-CHO[/tex] group is directly attached to the alkyl group of carbon.

(5) [tex]R-COOH[/tex] : It belongs to carboxylic acid functional group in which the the [tex]-COOH[/tex] group is directly attached to the alkyl group of carbon.

(6) [tex]R-COO-R^'[/tex] : It belongs to ester functional group in which the the [tex]-COO[/tex] group is directly attached to the two alkyl group of carbon.

[tex]R-NH_2[/tex] : It belongs to an amine functional group in which the the [tex]-NH_2[/tex] group is directly attached to the alkyl group of carbon.

[tex]R-X[/tex] : It belongs to halide functional group in which the the [tex]-X[/tex] group (all the halogens) is directly attached to the alkyl group of carbon.

From the above and from the question we conclude that, some uses of functional groups are given in which the an oxygen are present in all the functional groups.

Hence, the correct option is, (A) uses of functional groups involving oxygen.

It takes approximately 12.67 minutes for a communication to travel from Mars to Earth, calculated by dividing the average distance of 228 million km by the speed of light (300,000 km/s) and then converting the time from seconds to minutes.

To calculate the time it takes for a communication to reach Earth from Mars, you can use the formula for the speed of light:
Time = Distance / Speed. With Mars being an average of 228 million km away from Earth and radio waves traveling at the speed of light, which is approximately 300,000 km/s, you can compute the time in seconds and then convert the result into minutes.

First, find the time in seconds:

Time = 228,000,000 km / 300,000 km/s = 760 seconds.

Then, convert seconds into minutes:

Time = 760 s / 60 s/min = 12.67 minutes.

Therefore, it takes approximately 12.67 minutes for a communication to reach Earth from Mars.

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Answer:

0.1125 M

Explanation:

Molarity of a solution is number of moles of solute dissolved in 1 L of solution

600 mL of water is added to 200 mL of a 0.450 M solution of K₂Cr₂O₇

number of moles of K₂Cr₂O₇ remain the same but more water is added therefore volume changes making the solution more dilute

first we need to find the number of moles of K₂Cr₂O₇ already in solution

molarity = number of moles of K₂Cr₂O₇ / volume of solution

substituting values in the equation

0.450 mol/L = number of moles / 0.2 L

number of moles = 0.09 mol

there are 0.09 mol of K₂Cr₂O₇ and the new volume is 200 mL + 600 mL = 800 mL

molarity = 0.09 mol / 0.8 L

molarity = 0.1125 mol/L

new molarity is 0.1125 M

Base pairs.

Four + Five = Nine

The third letter in base is S.

IT ADDS UP.

In DNA, hydrogen bonds form base pairs between adenine and thymine or guanine and cytosine, which stabilize the double helix structure.

The hydrogen bonds between adenine (A) and thymine (T) or guanine (G) and cytosine (C) form base pairs that join the two strands of the DNA double helix. In DNA, adenine forms a base pair with thymine and guanine forms a base pair with cytosine. These base pairs are fundamental in the structure of the DNA double helix. The arrangement was suggested by Chargaff's Rules and is consistent with Watson and Crick's proposed model of DNA. Two hydrogen bonds form in an A-T base pair and three in a G-C base pair, maintaining the stability of the DNA structure.

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Answer:

5746.0 mL.

Explanation:

We can use the general law of ideal gas: PV = nRT.

where, P is the pressure of the gas in atm.

V is the volume of the gas in L.

n is the no. of moles of the gas in mol.

R is the general gas constant,

T is the temperature of the gas in K.

If n and P are constant, and have two different values of V and T:

V₁T₂ = V₂T₁

V₁ = 6193.0 mL, T₁ = 62.3°C + 273 = 335.3 K.

V₂ = ??? mL, T₂ = 38.1°C + 273 = 311.1 K.

∴ V₂ = V₁T₂/T₁ = (6193.0 mL)(311.1 K)/(335.3 K) = 5746.0 mL.

Igneous rocks that cool slowly inside the Earth's crust have coarse-grained textures. Rocks that cool quickly on the Earth's surface are called extrusive or volcanic. Extrusive rocks with primarily light-colored minerals are felsic, likely rhyolite, while intrusive rocks with dark, high-density minerals are mafic, possibly gabbro.

1. When magma cools slowly within the Earth’s crust, it gives the crystals in the forming igneous rock time to grow, creating a coarse-grained texture often visible to the nake-d eye. This is known as phaneritic texture.

2. The rock that forms from lava cooling quickly on the Earth's surface would be classified as extrusive. Another term used to describe this type of igneous rock is volcanic.

3. The rock sample described is likely an extrusive igneous rock of felsic composition, possibly a rhyolite. This type of rock is primarily composed of light-colored minerals with few dark-colored minerals present.

4. The rock described is likely an intrusive igneous rock with a mafic composition. This might be a gabbro, which typically contains a high concentration of dark-colored, high-density minerals.

5. If gabbro is classified as an intrusive mafic igneous rock, it means that it was formed by magma cooling slowly within the Earth's crust (intrusive) and it is composed primarily of dark colored, high-density minerals (mafic).

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Igneous rocks are classified as intrusive or extrusive based on whether they cool slowly within Earth's crust or quickly on the surface, resulting in coarse-grained or fine-grained textures, respectively. A light-colored, surface-formed rock is likely extrusive and felsic, while a dark-colored, crust-formed rock is likely intrusive and mafic. Gabbro is an intrusive mafic igneous rock, meaning it has a coarse-grained texture and is composed of dark, dense minerals.

Igneous rocks are classified into two main types based on their formation process and resultant textures: intrusive (or plutonic) and extrusive (or volcanic).

1. When igneous rock forms from magma that cools slowly within Earth's crust, it is likely to have a coarse-grained texture due to the slow crystallization process that allows larger mineral crystals to form. This type of igneous rock is referred to as intrusive or plutonic.

2. Igneous rock that forms from lava cooling quickly on Earth's surface is classified as extrusive. This type of rock is also known as volcanic igneous rock, and it typically has a fine-grained texture due to the rapid cooling that allows only small crystals to form.

3. An igneous rock sample that formed on the surface of Earth and is composed mostly of light-colored minerals is likely an extrusive rock with a felsic composition, which means it is rich in silica. Common examples of this type include rhyolite or dacite.

4. An igneous rock that formed within Earth's crust and contains a high concentration of dark-colored, high-density minerals is likely an intrusive rock with a mafic composition, which means it is rich in magnesium and iron. This would typically correspond to a rock like gabbro.

5. Gabbro being an intrusive mafic igneous rock means that it formed within the crust from slowly cooled magma, and it is composed primarily of dark minerals like pyroxene and olivine, which are higher in density compared to the minerals that compose felsic rocks.

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Answer:

C: metals donate electrons to non metals

Explanation:

Answer : The correct option is, (C) metals donate electrons to non metals

Explanation :

Covalent compound : Covalent compounds are the compound in which the atoms are covalently bonded.  The covalent bonds are formed by the equal sharing of the electrons and these bonds are formed between two non-metals.

Ionic compound : Ionic compounds are the compound in which atoms are bonded through the ionic bond.  The ionic bonds are formed by the complete transfer of electrons. That means the bond is formed when the metals donate electrons to the non-metals.

These bonds are formed between one metal and one non-metal.

Hence, the correct option is, (C) metals donate electrons to non metals

Answer:

Q1: 2.068 atm.

Q2: 0.7346 atm.

Q3: 336.7 mm Hg.

Q4: 393.7 K = 120.7 °C.

Q5: 694.1 mm Hg.

Q6: 397.1 K.

Q7: 676.5 mm Hg.

Q8: 72.68 kPa.

Explanation:

P₁T₂ = P₂T₁.

Q1:

P₁ = 2.0 atm, T₁ = 20.0°C + 273 = 293 K.

P₂ = ??? atm, T₂ = 30.0°C + 273 = 303 K.

∴ P₂ = P₁T₂/T₁ = (2.0 atm)(303 K)/(293 K) = 2.068 atm.

Q2:

P₁ = 0.55 atm, T₁ = 25.0°C + 273 = 298 K.

P₂ = ??? atm, T₂ = 125.0°C + 273 = 398 K.

∴ P₂ = P₁T₂/T₁ = (0.55 atm)(398 K)/(298 K) = 0.7346 atm.

Q3:

P₁ = 87.0 mm Hg, T₁ = 77.0 K.

P₂ = ??? atm, T₂ = 25.0°C + 273 = 298.0 K.

∴ P₂ = P₁T₂/T₁ = (87.0 mm Hg)(298 K)/(77 K) = 336.7 mm Hg.

Q4:

P₁ = 248.0 kPa, T₁ = 10.0°C + 273 = 283 K.

P₂ = 345.0 kPa, T₂ = ??? K.

∴ T₂ = P₂T₁/P₁ = (345.0 kPa)(283 K)/(248.0 kPa) = 393.7 K - 273 = 120.7 °C.

Q5:

P₁ = 750.0 mm Hg, T₁ = 22.0°C + 273 = 295 K.

P₂ = ??? mm Hg, T₂ = 0.0°C + 273 = 273 K.

∴ P₂ = P₁T₂/T₁ = (750.0 mm Hg)(273 K)/(295 K) = 694.1 mm Hg.

Q6:

P₁ = 599.0 mm Hg, T₁ = 40.0°C + 273 = 313 K.

P₂ = 760.0 mm Hg, T₂ = ??? K.

∴ T₂ = P₂T₁/P₁ = (760.0 mm Hg)(313 K)/(599 mm Hg) = 397.1 K.

Q7:

P₁ = 800.0 mm Hg, T₁ = 323 K.

P₂ = ??? mm Hg, T₂ = 273.15 K.

∴ P₂ = P₁T₂/T₁ = (800.0 mm Hg)(273.15 K)/(323 K) = 676.5 mm Hg.

Q8:

P₁ = 30.0 kPa, T₁ = - 150.0°C + 273 = 123 K.

P₂ = ??? kPa, T₂ = 25.0°C + 273 = 298 K.

∴ P₂ = P₁T₂/T₁ = (30.0 kPa)(298 K)/(123 K) = 72.68 kPa.

Answer:

yeast

Explanation:

Answer:

Explanation:

C

Answer:

D.

Each helium atom has a full valence electron shell, but each hydrogen atom only has one valence electron.

Explanation:

Atoms are made of protons, neutrons and electrons. Protons and neutrons are in the nucleus and electrons orbit in energy levels. Chemical properties of elements depend mostly on the number of electrons in the valence / outermost energy shell.

Elements that have an incomplete energy shell are more reactive as they try to gain a complete outer shell electron configuration either by losing electrons or gaining electrons from the valence energy shell.

He is a noble gas, which means it has a full valence electron shell therefore it is inert. H has one electron in the outer shell therefore its reactive by gaining or losing the outermost electron.

therefore H is more reactive than He as it has an incomplete valence electron shell.

D, L, A, L,?, j, b, ,, ,, ,,

Answer: um nose

Explanation:

The density of water is decreases by about 9% when it is in a frozen state.

Water expands when it freezes because of the unique structure of the water molecule. Water molecules are polar, meaning that they have a positive and negative end. The positive end of one water molecule is attracted to the negative end of another water molecule, forming hydrogen bonds.

When water is in a liquid state, the hydrogen bonds are constantly breaking and reforming. This allows the water molecules to move around freely. However, when water freezes, the hydrogen bonds become more rigid and the water molecules form a crystalline structure. This structure is less dense than the liquid state, which is why ice expands when it freezes.

The hydrogen bonds in ice force the water molecules to be further apart than they are in liquid water. This is because the hydrogen bonds have a specific angle and length that they must be in order to be stable. As a result, the water molecules cannot pack as tightly together in ice as they can in liquid water.

The expansion of water when it freezes has a number of important implications. For example, it allows ice to float on water, which is essential for life in cold climates. It also helps to protect plants and animals from freezing damage.

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is that all the information i can get for the quistion

Answer:

The correct answer is a mathematic model.

Explanation:

A mathematical model constitutes an abstract representation of a certain aspect of reality, and has a structure that is formed by the elements that characterize the aspect of modeled reality and by the relationships between these elements called equations. Once the mathematical model is constructed, it is possible to extract from it properties and characteristics of the relations between the elements that would otherwise remain hidden.

Have a nice day!

Answer:2 AL + FEN2 = 2 ALN + FE

Explanation: AL might be an improperly capitalized: Al. One of your compounds is AL (A and L). Did you mean Al (aluminum)?

FEN2 might be an improperly capitalized: FeN2. ALN might be an improperly capitalized: AlN

FE might be an improperly capitalized: Fe

Answer:

[tex]\boxed{1.45 \times 10^{8}}[/tex]

Explanation:

A number in scientific notation has the form N × 10ⁿ

where N is a decimal number called the mantissa and n is an integer called the exponent.

We must have 1 ≤ N < 10

Step 1. Determine the mantissa

Move the decimal place to the left to create a new number between 1 and 10.

145 000 000 ⟶ 1.450 000 00; N = 1.45

Step 2. Determine the exponent.

The exponent is the number of times you moved the decimal to get the mantissa.

You moved the decimal eight places to the left, so the exponent n = 8.

Step 3. Write the number in scientific notation

The number in scientific notation is [tex]\boxed{1.45 \times 10^{8}}[/tex].

Answer:

Ok so its not dust particles i have proof i choose it and it was wrong but i have been working and the answer is sun rays i looked at  images online and i found the same image so its sun rays i hope this helps.

In this illustration, the rings around the Sun represent sun rays. Sunlight, or radiation from the Sun, is a bundle of electromagnetic waves that range from infrared (IR) to ultraviolet rays (UV)

Crepuscular rays are produced when sunlight passes through gaps in clouds and continues into an environment that contains dust and/or haze. They are also known as sun rays and sunbeams.

Sunlight, specifically infrared, visible, and ultraviolet light, is a type of electromagnetic radiation emitted by the Sun.

On Earth, sunlight is reflected and filtered by the atmosphere, and when the Sun is above the horizon, it is seen as daytime.

Sunlight, or radiation from the Sun, is a bundle of electromagnetic waves that range from infrared (IR) to ultraviolet rays (UV). The electromagnetic spectrum naturally includes visible light, which lies between IR and UV.

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Answer:

3Fe2O2---> Fe3O4

Explanation:

You need to add three to the left side to make it equal to the one on the right, and add a 2 since you can't change the subscripts

Answer:

The balanced chemical reaction is:

[tex]3Fe+2O_2\rightarrow Fe_3O_4[/tex]

Explanation:

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.

While balancing the chemical equation balance all the atoms of elements except oxygen atom which will be done in the last.

[tex]Fe+O_2\rightarrow Fe_3O_4[/tex]

Step 1: Write three in front of iron;

[tex]3Fe+O_2\rightarrow Fe_3O_4[/tex]

Step 2: Now write two in front of oxygen gas;

[tex]3Fe+2O_2\rightarrow Fe_3O_4[/tex]

The balanced chemical reaction is:

[tex]3Fe+2O_2\rightarrow Fe_3O_4[/tex]

According to reaction, 3 moles of iron reacts with 2 moles of oxygen gas to give 1 mole of ferric oxide.

Answer:

They are both involved in gas exchanges.

Explanation:

This is the answer because:

1) Gas exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. Inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.

2) Also, capillaries are located inside the lungs. Therefore, whenever we breathe in air we exchange gasses.

Hope this helps! :D

One similarity between the lungs and capillaries is that they are both involved in gas exchanges.

Capillaries may be defined as a network of blood vessels that supplies blood as well as oxygen throughout the body.

Both the lungs and the capillaries are actively involved in the exchange of gases in and out of the body. The capillaries are connected to the walls of the alveoli where oxygen and carbon dioxide diffuse. Carbon dioxide is exhaled outside by the lungs, while the oxygen is attached to the RBCs and travels to the heart.

Therefore, one similarity between the lungs and capillaries is that they are both involved in gas exchanges.

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Answer:

= 72.73%

Explanation:

The percentage by mass of an element is given by;

% element = total mass of element in compounds/molar mass of compound × 100

The mass of oxygen in carbon dioxide = 32 g

Molar mass of CO2 = 44 g

Therefore;

% of O2 = 32/44 × 100%

             = 72.73%

Answer:

C

Explanation:

72.71%

Answer:

Molarity≅0.6522 mol/L

Explanation:

The solutions are homogeneous mixtures (that is, their properties and composition are uniform) of two or more substances. The substance that is in greater proportion is called solvent, and the substance or substances that are in a smaller proportion, solute.

The mole is an International Unit used to measure the amount of a substance.

Molarity (M) or Molar Concentration is the number of moles of solute that are dissolved in a given volume of solution. It is expressed in the units (moles / liter).

[tex]Molarity=\frac{number of moles of solute}{solution volume}[/tex]

In this case, the solute is NaCl,and you know:

Then:

[tex]Molarity=\frac{1.5 mol}{2.3 L}[/tex]

Molarity≅0.6522 mol/L

The molarity of a solution if there are 1.5 mol of NaCl in 2.3 L of solution is 0.652M

Molarity = no. of moles (n) ÷ volume (L)

Molarity = 1.5mol ÷ 2.3L

Molarity = 0.652M

Therefore, the molarity of a solution if there are 1.5 mol of NaCl in 2.3 L of solution is 0.652M.

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Answer:

B.

Explanation:

Answer:

11.99 % ≅ 12.0%.

Explanation:

∵ mass % = [mass of solute/mass of solution] x 100.

mass of solute (CaCl₂) = 8.87 g & mass of solution = 8.87 g + 65.1 g = 73.97 g.

∴ mass % of (CaCl₂) = [mass of solute/mass of solution] x 100 = ( 8.87 g/ 73.97 g) x 100 = 11.99 % ≅ 12.0%.

Answer: iits 9.g

Explanation:

A compound is a substance made up of atoms of two or more different elements joined by chemical bonds. A mixture is a combination of two or more substances that are not chemically combined.

Answer:

a mixture has multiple atoms or chemicals in it a compound is one solid atom packed tokether to creatat a compound

Explanation:

Answer:

286 kPa

Explanation:

Boyles law states that volume of gas is inversely proportional to pressure o gas for a fixed amount of gas at constant temperature

P1V1 = P2V2

where P1 is pressure and V1 is volume at first instance

P2 is pressure and V2 is volume at the second instance

substituting the values in the equation

229 kPa x 4.0 L = P2 x 3.2 L

P2 = 286.25 kPa

the new pressure is 286 kPa

Bigtcuvpifyvipycrx txeZzerxtuciutesrc

I think the second choice but I might be wrong

Answer:

B

Explanation:

There is less air pressure outside the door than inside the door.

Answer:

Cells divide to reproduce. There are two primary methods used, one for somatic cells, which compose the organism’s body, and one for reproductive cells, or gametes.

Scientists call the process of somatic cell division mitosis. Mitosis has six distinct steps in which the cell organizes and copies the DNA in the nucleus. Once copied, each new cell has its own copy of the DNA. The six steps of mitosis are prophase, prometaphase, metaphase, anaphase, telophase and cytokinesis. Some authorities consider the non-dividing portion of the cell’s lifecycle, known as interphase, to be one of seven steps involved in mitosis; however, interphase cells are not actively dividing.

Sex cells, such as sperm or eggs, must divide differently. Sex cells only possess one-half of the DNA that makes up a new animal. That way, when they combine, the resulting organism gets half of its DNA from its mother and half from its father. Because sex cells only want half of the DNA in each cell, they go through a different division process called meiosis. In meiosis, the cells split a second time, which yields four daughter cells rather than two as with mitosis; however, this provides each daughter cell with 23 chromosomes in contrast to the 46 chromosomes in somatic cells.