pls help me i dont understand this question

Answer: D

Explanation: cells are alive

Answer:

D

Explanation:

Cells are the most basic unit of life.

Answer:

Chemical change

Explanation:

If you start with substance A and B and you produce C, you have witnessed a chemical change and this is a synthesis or combination reaction.

    A   +   B  →  C

We know this because from the two different reactants, a new substance C has been formed.

The substance C is produced via a chemical change.

In a chemical change, new kinds of products are usually formed and the reaction is not easily reversible.

Answer:

Mass = 824.57 g

Explanation:

Given data:

Mass of bromine = ?

Number of moles of bromine = 5.16 mol

Solution:

Formula:

Mass = number of moles × molar mass

Molar mass of bromine = 159.8 g/mol

by putting values,

Mass = 5.16 mol × 159.8 g/mol

Mass = 824.57 g

Answer:

How many atoms of hydrogen and oxygen are in 2 molecules of water? ... 7) Using complete sentences, explain the difference between the chemical ... (s) solid, (l) liquid, (g) gas, (aq) aqueous solution (dissolved in water).

Explanation:

hope this helps✌️

Answer:

O Chlorine is more reactive than bromine.

Explanation:

From this experiment we can conclude that chlorine is more reactive than bromine and it is the reason why the reaction is able to proceed.

Answer:

What can be said about these common forms of sulphur is that;

(B) They will exhibit same chemical properties

Explanation:

Allotropy is the property of an element to exist in two or more forms in the same physical state

Allotropes have several similar chemical  properties but differ in their physical properties, such as the white, pale yellow to totally colorless diamond and the gray graphite

Sulphur can exist in several allotropic forms, and carbon is the only element that has more allotropes than sulphur

The sulphur allotropes includes S₂, S₆, and S₅ have similar chemical properties but different physical properties.

The correct option is;

What can be said about these common forms of sulphur is that they have the same chemical properties

Answer:

detail is given below.

Explanation:

This law was given by French chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

For example:

In given photosynthesis reaction:

6CO₂ + 6H₂O  → C₆H₁₂O₆ + 6O₂

The given equation is balanced chemical equation of photosynthesis. There are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass.

If equation is not balanced,

CO₂ + H₂O  → C₆H₁₂O₆ + O₂

It can not follow the law of conservation of mass because mass is not equal on both side of equation.

Answer:

Volume in L = 0.50 L

Explanation:

Given data:

Molarity of solution = 0.1850 M

Mass of BaCl₂ = 19.30 g

Volume of solution = ?

Solution:

First of all we will calculate the number of moles of solute:

Number of moles = mass/molar mass

Molar mass of BaCl₂ = 208.23 g/mol

Number of moles = 19.30 g / 208.23 g/mol

Number of moles = 0.093 mol

Volume of solution:

Molarity = number of moles of solute / volume of solution in L

0.1850 M = 0.093 mol / Volume in L

Volume in L = 0.093 mol / 0.1850 M  (M= mol/L)

Volume in L = 0.50 L

The following that is not a way to measure a race car's motion is its velocity. The correct option is b.

Motion is a phenomenon that changes the position of an object with respect to time. The motion needs a force to change the position, and motion needs some energy that can be potential energy or a force.

Velocity is the speed of any object that is in motion in a particular direction. It tells the rate of change of motion of an object. It is a scalar quantity.

Motion is the result of force. Force can be measured by multiplying the mass by acceleration.  So the variables that would be needed to calculate a race car's motion will be acceleration and the mass of the car, and the resistances.

Thus, the correct option is b. it’s velocity.

To learn more about motion, refer to the link:

https://brainly.com/question/3421105

#SPJ2

Answer:

1.08 x 10²⁵molecules

Explanation:

From the mole concept we know that ;

      1 mole of any substance contains 6.02 x 10²³ molecules

This number is the Avogadro's number.

 So;

  18 mole of CH will contain:

       Number of molecules of CH  = 18 x 6.02 x 10²³ = 1.08 x 10²⁵molecules

The number of molecules is therefore 1.08 x 10²⁵molecules

Answer:

5*10^25 atoms of carbon

Explanation:

Answer:

Chemical change

Explanation:

If two types of matter reacts or are combined and energy is given off, the type of change that might have occurred is a chemical change.

A chemical change is one in which a new kind of matter is formed.

It is always accompanied by energy changes.

The process is not easily reversible.

Answer:

An opinion.

Explanation:

In physics, Sir Isaac Newton's first law of motion is known as law of inertia and it states that, an object or a physical body in motion will continue in its state of motion at continuous velocity (the same speed and direction) or, if at rest, will remain at rest unless acted upon by an external force.

The statement, "Roller coasters are the best use of Newton's laws of motions" is an opinion because it is not based on any evidence, facts or has a proof to back it up.

In English literature, an opinion is considered to be more like a claim.

A claim can be defined as a statement that is used by a writer to prove, substantiate or support an argument. Thus, a claim is an assertive statement expressed by a writer to prove that an argument is true or real.

Answer:

The water level in the pipe went down.] ... [The hot water in the cup heated up the water particles inside the bottle. They began to move more. Greater motion (kinetic energy) pushed the particles farther apart, resulting in expansion.

Answer:

1.5 moles of sodium chloride are present.

Explanation:

Given data:

Number of moles of sodium chloride = ?

Number of atoms of sodium chloride = 9.07×10²³

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

9.07×10²³ atoms  × 1 mol / 6.022 × 10²³ atoms

1.5 moles of sodium chloride are present.

Answer:

[OH⁻] = 3.34x10⁻³M; Percent ionization = 0.54%; pH = 11.52

Explanation:

Kb of the reaction:

NH3 + H2O(l) ⇄ NH4+ + OH-

Is:

Kb = 1.8x10⁻⁵ = [NH₄⁺] [OH⁻] / [NH₃]

As all NH₄⁺ and OH⁻ comes from the same source we can write:

[NH₄⁺] = [OH⁻] = X

And as [NH₃] = 0.619M

1.8x10⁻⁵ = [X] [X] / [0.619M]

1.11x10⁻⁵ = X²

3.34x10⁻³ = X = [NH₄⁺] = [OH⁻]

% ionization:

[NH₄⁺] / [NH₃] * 100 = 3.34x10⁻³M / 0.619M * 100 = 0.54%

pH:

As pOH = -log [OH-]

pOH = 2.48

pH = 14 - pOH

Answer:

5425440 μm

Explanation:

From the question given above,

Length (in ft) = 17.8 ft

Length (in μm) =?

Next, we shall convert 17.8 ft to in. This can be obtained as follow:

1 ft = 12 in

Therefore,

17.8 ft = 17.8 ft × 12 in / 1 ft

17.8 ft = 213.6 in

Next, we shall convert 213.6 in to cm. This can be obtained as follow:

1 in = 2.54 cm

Therefore,

213.6 in = 213.6 in × 2.54 / 1 in

213.6 in = 542.544 cm

Finally, we shall convert 542.544 cm to μm. This can be obtained as follow:

1 cm = 10⁴ μm

Therefore,

542.544 cm = 542.544 cm × 10⁴ μm / 1 cm

542.544 cm = 5425440 μm

Therefore, 17.8 ft is equivalent is equivalent to 5425440 μm

Answer:

Explanation:

A is the correct answer.

If you found my answer useful then please mark me brainliest

Answer:

I put this so the guy up top can have brainliest

Explanation:

your welcome

Answer:

During exercise, your body may need three or four times your normal cardiac output, because your muscles need more oxygen when you exert yourself. During exercise, your heart typically beats faster so that more blood gets out to your body.

Answer:

I'd myself say it's because a lot of people are fat but here's the real answer ;)

During exercise, your body may need three or four times your normal cardiac output, because your muscles need more oxygen when you exert yourself. During exercise, your heart typically beats faster so that more blood gets out to your body.

Answer:

d. Electrons have a negative charge and are lighter than protons

Explanation:

The best statement that describes electrons is that electrons are negatively charged and are lighter than protons.

There are three known subatomic particles which are:

The mass of the protons and neutrons are similar.

Electrons are lighter than both protons and neutrons.

Answer:

Each sample has the same number of molecules.

Explanation:

Just took the quiz on edge 2021

Taking into account the definition of Avogadro's number, each sample has the same number of molecules.

Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole.

Avogadro's number applies to any substance.

Avogadro's number applies to any substance. This means that the number of molecules in 1 mol of oxygen is equal to the number of molecules in 1 mol of nitrogen.

Finally, the correct answer is the third option: each sample has the same number of molecules.

Learn more about Avogadro's Number:

brainly.com/question/1445383

brainly.com/question/1528951

Answer:

sample 2

Explanation:

hope this helps

Answer:

Pb₂O₄

Explanation:

The given species are:

        Pb⁴⁺               O²⁻  

Now, to solve this problem, we use the combining powers which corresponds to the number of electrons usually lost or gained or shared by atoms during the course of a chemical combination.

                                          Pb⁴⁺               O²⁻  

Combining power               4                    2

Exchange of valencies        2                    4

Now the molecular formula is  Pb₂O₄

Answer:

We know that kinetic energy is one of the forms of internal energy, so the release of heat from an object causes a decrease in the average kinetic energy of its particles.

Answer:

( NH4NO3 -> N2+O2+H2O)

Explanation:

40g= 14g+8g+X

x=18g

hope that helps :)

Answer:

10 electrons

Explanation: