answer choices
a. 13
b. 15
c. 28
d. 30
:))

Answer:

Chemical bonds. Chemical bonds are the connections between atoms in a molecule. ...

Covalent Bonds. Chemical bonds are the forces of attraction that tie atoms together. ...

Ionic Bonds. ...

Bonds, Stability, and Compounds.

Answer:

Ionic bonding.

Covalent bonding.

Metallic bonding.

Answer:

whats your question

Explanation:

Answer:

Solubility

Explanation:

If its not that the answer is Dissolvable.... you didn't give a word bank.

:))))))))))

Answer:D

Explanation:

Answer: A

Explanation: equilibrium is where all the paricles are at the

Answer: C- 1.65 moles

Explanation:

HCl = 1 + 35.45 = 36.45 g/mol    

Answer:

plants

Explanation:

Answer:

dk

Explanation:

Answer:

1. 5.24 g

2. 75.4%

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

MgCl₂ + Na₂SO₄ —> MgSO₄ + 2NaCl

Next, we shall determine the mass of MgCl₂ that reacted and the mass of MgSO₄ produced from the balanced equation. This can be obtained as follow:

Molar mass of MgCl₂ = 24 + (35.5×2)

= 24 + 71

= 95 g/mol

Mass of MgCl₂ from the balanced equation = 1 × 95 = 95 g

Molar mass of MgSO₄ = 24 + 32 + (16×4)

= 24 +32 + 64

= 120 g/mol

Mass of MgSO₄ from the balanced equation = 1 × 120 = 120 g

SUMMARY:

From the balanced equation above,

95 g of MgCl₂ reacted to produce 120 g of MgSO₄.

1. Determination of the ideal yield of magnesium sulfate, MgSO₄.

From the balanced equation above,

95 g of MgCl₂ reacted to produce 120 g of MgSO₄.

Therefore, 4.15 g of MgCl₂ will react to produce = (415 × 120)/95 = 5.24 g of MgSO₄.

Thus, the ideal yield of magnesium sulfate, MgSO₄ is 5.24 g

2. Determination of the percentage yield.

Actual yield of MgSO₄ = 3.95 g

Ideal yield of MgSO₄ = 5.24 g

Percentage yield =?

Percentage yield = Actual yield / Ideal yield × 100

Percentage yield = 3.95 / 5.24 × 100

Percentage yield = 395 / 5.24

Percentage yield of MgSO₄ = 75.4%

Answer:

Answer is A.

Explanation:

I hope it's helpful!

Answer:

Mass = 0.96 g

Explanation:

Given data:

Volume of oxygen = 840cm³

Temperature = at room = 25°C

Pressure = at room = 1 atm

Mass of oxygen = ?

Solution:

Volume of oxygen = 840 cm³ × 1 L /1000 cm³ = 0.84 L

Temperature  = 25 +273.15k = 298.15 K

Formula:

PV = nRT

n = PV/RT

R = 0.0821 atm.L/mol.K

n = 1 atm × 0.84 L / 0.0821 atm.L/mol.K ×  298.15 K

n = 0.84 atm.L / 24.48 atm.L/mol

n = 0.03 mol

Mass of oxygen:

Mass = number of moles × molar mass

Mass = 0.03 mol × 32 g/mol

Mass = 0.96 g

Answer:

B hope this helps

Explanation:

The density of a substance describes how closely its molecules are packed. Despite the fact that ice is a solid form, an ice cube contains many pores in and the molecules are more spread in the state than that in liquid state of water.

Density of a substance is the measure of its mass per unit volume. It describes how closely packed its molecules within a given volume. If the molecules have enough space to spread they will be less dense.

The objects which are less dense than water will float in it. Whereas which are having more density will sink on it. Ice floats on water because, ice is less dense than water.

An ice cube has a pore structure and one ice cube contains fewer water molecules and which are spread through the porous structure. Therefore, water in liquid state is more dense than ice.

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Answer:

the answer is B rising action! :)

Answer:

Explanation:

The enzyme lactase acts as a catalyst to facilitate the reaction and make it happen very quickly. This enzyme is made u.

do the rest

hope it helps

Enzyme lactase catalyzes the hydrolysis of the glycosidic bond of lactose to form galactose and glucose.

Lactase can be described as an enzyme produced by many organisms. Lactase is located in the small intestine of humans and other mammals. It is essential to accomplish the digestion of milk and it breaks down lactose that gives milk its sweetness.

A person with a deficiency of lactase, and who consume dairy products, may experience the symptoms of lactose intolerance. Lactase is a part of the β-galactosidase family of enzymes and is a glycoside hydrolase involved in the hydrolysis of lactose into constituent galactose and glucose monomers.

The β-glycosidic bond in D-lactose in metabolism is hydrolyzed to form D-galactose and D-glucose, which can be absorbed into the bloodstream. The optimum temperature of the human lactase is about 37 degrees Celcius and the optimum pH of the human lactase is equal to 6.

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Answer:

Explanation:

In one mole of carbon, there are 6.02×10^23 atoms. So in two moles, there will be twice that: 1.204×10^24

Answer:

m = 2.18x10¹⁵ tons of ice

Explanation:

To solve this exercise, we need to work with the same units of conversion. In this case let's see the conversion of every unit here:

1 mi = 5280 ft

1 ton = 1000 kg

1 kg = 1000 g

1 mL = 1 cm³

1 mi = 1609.34 m or 160,934 cm

Now that we know the units, let's analyze the data.

The landscape has a 500,000 mi² of area, this is however without including the ice. The ice is apart, and has a 7520 ft of height. And if the landscape wouldn't have ice, then the height will be 1500 ft only.

With that data, we can know the actual height of the ice by a simple difference:

Hi = Hli - Hl

Where:

Hi: Height of ice

Hli: Height of ice + landscape

Hl: Height of landscape

Applying this expression, the height of ice is:

Hi = 7520 - 1500 = 6020 ft of ice

Now that we know the height of the ice, we can calculate the volume of whole landscape. But first, let's do the conversion of foot to mile:

Hi = 6020 ft * (1 mi/5280 ft) = 1.14 mi

And now, let's calculate the volume of the landscape in mile, and then, to centimeter:

V = 1.14 mi * 500,000 mi² = 570,000 mi³

To convert the cubic mile to cubic centimeter we just do the following:

V = 570,000 mi³ * (160934 cm / 1 mi)³ = 2.38x10²¹ cm³

Now, we can get the mass of the ice using the given density of ice (d = 0.917 g/cm³)

If d = m/V  

then m = d * V

Replacing the data:

m = 0.917 g/cm³ * 2.38x10²¹ cm³

m = 2.18x10²¹ g

Finally, the tons of ice will be:

m = 2.18x10²¹ g * (1 kg / 1000 g) * (1 ton / 1000 kg)

Hope this helps

Answer:

40 Grams

Explanation:

Fe2O3 is 2 parts Iron 3 parts Oxygen.

Assuming the molecular weights of both are equivalent (ideal elemental law), it is a 2:3 ratio, or 2/5 of the total.

2/5 of 100 is 40, so the answer is

40 grams

The relative molecular mass of the gas​ : 64 g/mol

Given

Helium rate = 4x an unknown gas

Required

The relative molecular mass of the gas​

Solution

Graham's Law

[tex]\tt \dfrac{r_1}{r_2}=\sqrt{\dfrac{M_2}{M_1} }[/tex]

r₁=4 x r₂

r₁ = Helium rate

r₂ = unknown gas rate

M₁= relative molecular mass of Helium = 4 g/mol

M₂ = relative molecular mass of the gas​

Input the value :

[tex]\tt \dfrac{4r_2}{r_2}=\sqrt{\dfrac{M_2}{4} }\\\\16=\dfrac{M_2}{4}\\\\M_2=64~g/mol[/tex]

Answer:

2.35

Explanation:

A 1.00-L flask was filled with 2.00 moles of gaseous SO₂ and 2.00 moles of gaseous NO₂ and heated. After equilibrium was reached, it was found that 1.21 moles of gaseous NO was present. Assume that the reaction

SO₂ + NO₂ ⇌ SO₃ + NO

occurs under these conditions. Calculate the value of the equilibrium constant, K, for this reaction.

Step 1: Calculate the molar concentrations

Since the reaction takes place in a 1.00 L flask, the molar concentrations are:

[SO₂]i = 2.00 M

[NO₂]i = 2.00 M

[NO]eq = 1.21 M

Step 2: Make an ICE chart

        SO₂ + NO₂ ⇌ SO₃ + NO

I       2.00   2.00       0        0

C        -x       -x         +x       +x

E    2.00-x  2.00-x    x         x

Step 3: Calculate the concentrations at equilibrium

The concentration of NO at equilibrium is 1.21 M. Then, x = 1.21.

[SO₂]eq = 2.00-1.21 = 0.79 M

[NO₂]eq = 2.00-1.21 = 0.79 M

[SO₃]eq = x = 1.21 M

[NO]eq = x = 1.21 M

Step 4: Calculate the value of the equilibrium constant, K, for this reaction

K = [SO₃] × [NO]/[SO₂] × [NO₂]

K = 1.21²/0.79² = 2.35

Explanation:

A compound is a pure substance formed by the combination of two or more kinds of atoms or elements joined together in a definite grouping.

An mixture is an impure substance made up of different types of substances.

Here are some of the differences between them;

Examples of compounds are water, sodium chloride, hydrochloric acid

                     Mixtures are air, ocean water, alloys, et.c

Answer:chlorophyll

Explanation:

The part of leaves that is responsible for absorbing sun's energy is chloroplast.

A chloroplast is an organelle found within the cells of plants and certain algae that is responsible for photosynthesis, which is the process by which solar energy is converted into chemical energy for growth.

Small organelles called chloroplasts are found inside plant cells and store sunlight energy.

The chloroplast's thylakoid membranes contain a light-absorbing pigment called chlorophyll, which is responsible for the plant's green color.

They are in charge of photosynthesis, which is the process of converting light energy into sugar and other organic molecules that plants and algae use as food.

They also produce amino acids and lipids, which are required for the production of chloroplast membranes.

Thus, the chloroplast is the part that traps the energy of the Sun.

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Answer:

I'd say the most reasonable answer is perspective.

Explanation:

"Point of view" is about who is telling and sharing the details in what you are writing or reading. I'm not 100% sure because the word "perspective" doesn't seem like the right word to use, but it's better than the other two in my opinion.

Answer:

No

Explanation:

i honestly don't know

Answer:

2450 mg

Explanation:

From the given information:

The total weight of the capsule = 12.5 mg + 37.5 mg

= 50 mg

The percentage of drug in each capsule = [tex]\dfrac{12.5}{50} \times 100[/tex]

= 25%

= 0.25

To make 0.5 mg of drug in each  100 mg of powder after dilution;

Then, the drug percent in each capsule after dilution is:

[tex]=\dfrac{0.5}{100}\times 100[/tex]

= 0.5%

= 0.005

Suppose (p) mg represent the amount that is added to the diluent in the given capsule. Then;

The total amount is = (50 + p) mg

Since the amount of the drug = 12.5 mg

Then the concentration  [tex]=\dfrac{12.5}{50 + x}[/tex] which needs to be equal to the needed concentration that is diluted.

i.e.

[tex]\dfrac{12.5}{50 + x} = 0.005[/tex]

By cross multiply;

(50 + x) 0.005 = 12.5

(50 × 0.005) + (0.005x) = 12.5

0.25 + 0.005x = 12.5

0.005x = 12.5 - 0.25

0.005x = 12.25

x = 12.25 / 0.005

x = 2450 mg

Thus, there is a need for an additional 2450 mg to make a dilution that compass 0.5 mg of drug in 100 mg powder.

Answer:

Yttrium

Explanation:

If you somehow subtracted a proton from a Zirconium atom, it would become a Yttrium atom.

When the number of protons in an atom changes a new element is directly formed. The difference between one atom and the other is the based on the number of protons they contain.

Therefore, when Zirconium loses a proton, it changes to Yttrium which is the atom before Zirconium.

Such reactions as this are very common with nuclear reactions. During a nuclear reaction, the nucleus of an atom changes stability.

Answer:

Government programs aim to increase incentives for consumers and producers to move toward energy efficiency.

Explanation:

Government programs aim to increase incentives for consumers and producers to move toward energy efficiency.

Based on the complete text, it is clear to see that the main point of the passage is A. Ultraviolet rays can cause chemical reactions.

This refers to the theme of a text that is used in order to show the message that an author wants to convey in a given text that he wants his readers to understand and grasp.

Hence, we can see that from the complete text which can be found on the official website of BBC news site, the story is told about the ultraviolet rays that were found to cause chemical reactions and discolored some parts of the paintings by Vincent Van Gogh,

This is further explained as the bright yellows in the paintings chemically reacted and thus turned into brown color and this shows that option A is the correct answer that shows the central idea or main point of the text.

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