please helpppppppppppp

Answer:

Measurement helps in buying and selling goods

Measurement helps in doing various science

experiment

Measurement is used in our daily life

Measurement is essential for making roads, bridge etc

Answer:

B or the second answer.

Explanation:

It's heat transfer and the objects aren't directly touching. B is the only answer that fits.

Hope this helps!

Answer:

b

Explanation:

Answer:

232 g.

Explanation:

12.9 mol x 18.106g = 232 g H₂O

Answer:

4^4, or 256

Explanation:

When dividing numbers with exponents and the same base, you will subtract from the exponents and keep the base the same.

Answer:

Option 1

Explanation:

Harry: *wakes up and finds himself at the bottom of a mountain slope and asks, "Where are we?"

Harry: "Are we in Iceland?"

Hans: "Nej."

The Professor: *Gets up and says, "what do you mean? No----What are your reasons?"

Harry: *Rises* "No, Hans is wrong."

After all the innumerable surprises of this journey, a yet more singular one was reserved to us. I expected to see a cone covered by snow, by extensive and widespread glaciers, in the midst of the arid deserts of the extreme northern regions, beneath the full rays of a polar sky, beyond the highest latitudes.

*Time passes while we try to figure out what is happening and where we are. Harry finds that he was saved from death because Hans had saved him.*

Answer:

40g

Explanation:

Given parameters:

Number of moles  = 1mol

unknown:

mass of Ca  = ?

Solution:

The number of moles of a substance is related to mass using the expression below;

    Mass = number of moles x molar mass

Molar mass of Ca = 40g/mol

     So;

          Mass of Ca = 1 mol  x 40g/mol  = 40g

Answer:

0.5 M

General Formulas and Concepts:

Chemistry - Aqueous Solutions

Explanation:

Step 1: Define

2.0 mol glucose

4.0 L glucose solution

Step 2: Find Molarity

The answer to the question, how many photons per second are emitted from the laser is d. 1.84 × 10¹⁵ photons/sec

Since the red laser pointer emits light of wavelength 488 nm, we need to find the energy of each photon from

E = hc/λ where h = Planck's constant = 6.63 × 10⁻³⁴ Js, c = speed of light = 3 × 10⁸ m/s and λ = wavelength of light = 488 nm = 488 × 10⁻⁹ m

Substituting the values of the variables into the equation, we have

E = hc/λ

E = 6.63 × 10⁻³⁴ Js × 3 × 10⁸ m/s ÷ 488 × 10⁻⁹ m

E = 19.89 × 10⁻²⁶ Jm ÷ 488 × 10⁻⁹ m

E = 0.04076 × 10⁻¹⁷ J per photon

E = 4.076 × 10⁻¹⁹ J per photon

Since the laser emits 7.5 × 10⁻⁴ J per second, the number of photons emitted from the laser per second = energy per second/energy per photon

= 7.5 × 10⁻⁴ J per second ÷ 4.076 × 10⁻¹⁹ J per photon

= 1.84 × 10¹⁵ photons/sec

The answer to the question, how many photons per second are emitted from the laser is d. 1.84 × 10¹⁵ photons/sec

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Answer:

Decyne: C10H18

Hope it helps! please mark me brainliest..

Merry Christmas good day

The general formula for alkynes is CnH2n-2

the number of carbon atoms is 10 so the number of hydrogen atoms will be 10*2-2=20-2=18hydrogen atoms

the molecular formula for this alkyne is :

C₁₀H₁₈ which is called decyne

Answer:

–0.16 m

Explanation:

From the question given above, the following data were obtained:

Time (t) = 0.18 s

Acceleration due to gravity (g) = –9.81 m/s²

Height (h) =?

We can obtain how far the ruler will fall by using the following equation:

H = ½gt²

H = ½ × –9.81 × 0.18²

H = ½ × –9.81 × 0.0324

H = –0.16 m

Thus, the ruler will fall –0.16 m before you will catch it.

Answer:

it losses one neutrons that is hydrogen

Answer:

The balanced chemical equation:

3 NH₃ + H₃PO₄ → (NH₄)₃PO₄

From the equation we see:

3 moles of NH₃ gives 1 mole (NH₄)₃PO₄

0.085 mole NH₃ will gives ?? mole (NH₄)₃PO₄

By cross multiplication:

number of moles of (NH₄)₃PO₄ = 0.085 * 1/3 = 0.028 mole

Explanation:

Answer:

31. C

32. D

33. B

Explanation:

31. A plant cell is an eukaryotic cell i.e. it contains a membrane-bound nucleus, located CENTRALLY. The nucleus is the largest organelle in the plant cell. The cell/plasma membrane bounds the cell while the chloroplast organelle (site of photosynthesis) is also located in the plant cell. Based on this description, the image in OPTION C is correct.

32. Pottasium (K) is a highly reactive group 1 element. As stated in this question, pottasium reacts vigorously with water (H2O). This reactive property of K element is due to its valence electrons. However, elements in the same group as pottasium i.e same column on the periodic table will have the same number of valence electrons, hence, will behave chemically similar. Therefore, elements in the same column as pottasium will react the same way with water.

33. A reactant is a an element/compound in a chemical reaction that gets used up to form new products. They are usually the starting materials located on the left side of any equation. In this equation shown as:

2CuO + C → 2Cu + CO2

CuO and C are the REACTANTS while Cu and CO2 are the products.

Answer:

E = -0.76 V

Explanation:

The potential between the anode and the cathode is called standard reduction potential. It gives the tendency of the species to get reduced.

The given half reaction is :

[tex]Zn^{2+}(aq)+2e^{-}\rightarrow Zn(s)[/tex]

Zn²⁺ is the reduced form of Zn.

It is a stronger reducng agent.

Its standard reduction potential (E) has a sandard value.

E = -0.76 V

Hence, the correct option is (c).

Answer:

Both diseases affect the control of voluntary muscles.

Explanation:

Parkinson's disease is a progressive brain disease that affects movement. It affects the nerve cells that produce dopamine in the part of the brain called substantia nigra. The symptoms include shaking, stiffness, and difficulty with walking, balance, and coordination. Symptoms get worse with time, often leaving people with difficulty walking and talking.

ALS (amyotrophic lateral sclerosis) is a progressive nervous system disease that affects nerve cells in the brain and spinal cord. The first symptoms usually involve muscle weakness, and as the disease progresses, it results in the loss of muscle control.

Scientists don't know the exact cause of these diseases. As the cause is not known, there is no exact way to prevent them. There is no cure for them, either. The treatment is focused on the management of symptoms.

This is why the third option is the correct one.

Answer:

The correct answer is 0.3582 M.

Explanation:

Based on the given information, the volume of KOH given is 19.55 ml, the volume of sulfuric acid given is 20.20 ml, and the molarity of sulfuric acid is 0.3467 M. There is a need to find the molarity of KOH.

The formula to use in the given case is,

M1V1 = M2V2

Here M1 is the molarity of KOH, V1 is the volume of KOH, M2 is the molarity of sulfuric acid, and V2 is the volume of H2SO4.

Here V1 is 19.55 ml, M2 is 0.3467 M, and V2 is 2020 ml.

Now putting the values in the equation we get,

M1 * 19.55 = 0.3467 * 20.20

M1 * 19.55 = 7.00334

M1 = 7.00334/19.55

M1 = 0.3582 M

Hence, the molarity of the given KOH is 0.3582.

The molarity of a solution of potassium hydroxide is 0.3582M

To get the molarity of the solution of potassium hydroxide KOH, we will apply the formula;

[tex]C_1V_1=C_2V_2[/tex]

Given the following parameters;

C₂ = 0.3467M

V₂ = 20.20mL

V₁ = 19.55mL

C₁ = ?

Substitute the given parameters into the formula:

C₁ × 19.55 = 0.3467× 20.20

C₁ × 19.55 = 7.00334

C₁ = 7.00334/19.55

C₁ = 0.3582M

Hence the molarity of a solution of potassium hydroxide is 0.3582M

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Answer:

2 molecules

Explanation:

I don't know how to explain it

The chemical formula of water is H₂O. Then 1 mole of water weighs 18 gram. Hence, 80 gram of water is equal to 4.4 mole.

Chemical element symbols, numbers, and occasionally other symbols like parentheses, dashes, brackets, commas, and plus and minus signs are used in a chemical formula to represent information about the chemical proportions of the atoms that make up a certain chemical compound or molecule.

It displays the constituent elements and how many atoms of each element are found in a single complex molecule. It also represents the compound's molecular weight.

Water has the chemical formula H₂O. Water weights 18 grams per mole. 80 grams of water are therefore equivalent to 4.4 moles.

Thus, The chemical formula of water is H₂O. 80 grams of H₂ contain 4.4 molecules of water.

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Answer:

A

an element made of carbon and oxygen atoms.

So I think the answer is going to be A An element made of carbon and oxygen atoms.

digestion

does that answer it?

Answer:

860 cm/s

Explanation:

Let P = momentum of wrench-man system before throwing the wrench and P' = momentum of wrench-man system before throwing the wrench.

From the law of conservation of momentum,

P = P'

P = 0 (since both Astronaut and wrench were initially stationary) and P' = m₁v₁ + m₂v₂ where m₁ = mass of wrench = 4g = 0.004 kg v₁ = velocity of wrench after releasing the wrench = -15 m/s m₂ = mass of Astronaut = 70 kg and v₂ =  velocity of Astronaut after releasing the wrench.

So, P = P'

0 = m₁v₁ + m₂v₂

-m₁v₁ = m₂v₂

dividing both sides by m₂, we have

v₂ = -m₁v₁/m₂

substituting in the values of the variables, we have

v₂ = -0.004 kg × (-15 m/s)/70 kg

= 0.06 kgm/s ÷ 70 kg

= 8.6 × 10⁻⁴ m/s

= 860 × 10⁻² m/s

= 860 cm/s

The free energy change(Gibbs free energy-ΔG)=-8.698 kJ/mol

Given

Ratio of the concentrations of the products to the concentrations of the reactants is 22.3

Temperature = 37 C = 310 K

ΔG°=-16.7 kJ/mol

Required

the free energy change

Solution

Ratio of the concentration : equilbrium constant = K = 22.3

We can use Gibbs free energy :

ΔG = ΔG°+ RT ln K

R=8.314 .10⁻³ kJ/mol K

[tex]\tt \Delta G=-16.7~kJ/mol+8.314.10^{-3}\times 310\times ln~22.3\\\\\Delta G=-8.698~kJ/mol[/tex]

Answer:

when the Moon moves into the Earth's shadow

when the Sun, Earth, and Moon are exactly or very closely aligned with the Earth between the other two, and only on the night of a full moon

Explanation:

Answer:

The correct answer is - S- configuration.

Explanation:

Placing the numbers in order of the priorities of each reactant in the reaction is essential to determining the configuration of the reactant and product in the biological oxidation of isotopically labeled ethane.

CH3 - T- D is the correct order of the increasing of the priorties. so this is moving from CH3 to D which is Anti-clockwise which means the configuartion is S as we know clockwise movement is R configuarion and anti-clockwise in S configuartion.

Answer:

a.) x = 5

Explanation:

Answer:

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

[tex]volume = \frac{mass}{density} \\[/tex]

From the question we have

[tex]volume = \frac{20}{4} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

17. Yes, it represents a chemical reaction. This is because new substances were formed from the original substance.

18. (a) Formation of new substances

(b) Evolution or absorption of large quantity of heat

(c)Change in mass of substances

Explanation:

17. In the model above, molecules of a compound of carbon and hydrogen (molecular formula is C2H6) combines with molecular oxygen (O2) to produce two new substances; a compound composed of two oxygen atoms and one carbon atom (CO2) and another compound composed of two atoms of hydrogen and one atom of oxygen (H2O). Since the new substances formed are completely different from the original substances, it a chemical reaction. Also, a large volume of heat would have been given off.

18. To determine if a chemical reaction has occurred, the following observations can be looked out for.

a. Formation of new substances different entirely from the original substances

b. Evolution or absorption of large quantity of heat during the change. Check whether the vessel containing the substances gets hotter or colder.

c. Change in mass of substances. Since new substances are formed in a chemical reaction, there is usually a significant change in mass of the products and reactants.

Answer:

c

Explanation:

that is my dads answer

A pure substance composed of two or more different elements is a chemical compound.

When two or more atoms are chemically combined, we refer to such a combination as a chemical compound.

Since a chemical compound contains only a given set of elements which are chemically combined together, a chemical compound is also a pure substance.

Hence, a pure substance composed of two or more different elements is a chemical compound.

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