Can somebody help me please! Help would be much appreciated :))

Answer:

121.5g

Explanation:

from the equation:

2mol of Al react to give 3 mol of Zn

i.e 81g of Al will give 3×81/2 = 243/2 = 121.5g

Answer:

See explanation

Explanation:

All physical quantities are broadly classified into scalar quantities and vector quantities.

Scalar quantities have magnitude but do not have direction. Vector quantities have both magnitude and direction. Hence the main difference between a scalar quantity and a vector quantity is that a vector has direction while a scalar quantity does not.

Speed is a scalar quantity while velocity is a vector quantity. You have just specified a magnitude of 200 mph without mentioning its direction. This implies that you are referring to speed of the cars in the race and not velocity because velocity of the cars must indicate the direction!

Answer:

uhh its 497 miles

Explanation:

The boiling point of water increases as the amount of impurities dissolved in it increases. For our purposes, we will consider the non-electrolyte to be the dissolved impurity. The change in the boiling point can be calculated using the equation:

[tex]\Delta T_b = i \times K_b \times m[/tex]

where [tex]\Delta T_b[/tex] is the change in boiling point, [tex]i[/tex] is the van ‘t Hoff factor (whose value denotes the number of particles each formula unit of the dissolved substance dissociates into in water), [tex]K_b[/tex] is the boiling point elevation constant, and [tex]m[/tex] is the molality (moles of solute/kilogram of solvent) of the solution.

Right off the bat, since we're dealing with a non-electrolyte, the dissolved substance can be assumed not to dissociate in water. So, our van ‘t Hoff factor, [tex]i[/tex], would be 1 (by contrast, the [tex]i[/tex] for an ionic compound like NaCl would be 2 since, in water, NaCl would dissociate into two particles: one Na⁺ ion and one Cl⁻ ion). We're also given our [tex]K_b[/tex], which is 0.51 °C/m.

Assuming the normal boiling point of pure water to be 100 °C (a defined value for sig fig purposes), the change in boiling point from having dissolved 35.0 g of the non-electrolyte can be obtained by subtracting 100 °C from the final—elevated—boiling point of 101.25 °C:

[tex]\Delta T_b = 101.25\text{ }^o\text{C} - 100\text{ }^o\text{C} = 1.25\text{ }^o\text{C}[/tex]

Now, recall what we're asked to determine: the molecular mass of the dissolved substance. There is one unknown left in the equation: the molality of the solution. Let's first solve for that:

[tex]m = \frac{\Delta T_b}{K_b} = \frac{1.25^\text{ o}\text{C}}{0.51^\text{ o}\text{C}/m} \\ m = 2.45 \text{ mol solute/kg water}.[/tex]

Notice that we didn't include the i since its value is 1.

Now, what would happen if we multiplied our molality by the mass of water we've been given? We would be left with the moles of solute. And what are we asked to find? The molecular mass, or the mass per mole. We can accomplish this in two steps. Remember to convert your mass of water to kilograms:

[tex]2.45 \text{ mol solute/kg water} \times 0.045 \text{ kg water} = 0.110 \text{ mol solute.}[/tex]

And, finally, we divide the mass of our solute by the number of moles of solute:

[tex]\frac{35.0 \text{ g solute}}{0.110 \text{ mol solute}} = 317.5 \text{ g/mol}[/tex]

Our answer to two significant figures (which is the number of sig figs to which our [tex]K_b[/tex] is given) would be 320 g/mol.

Answer:

In a physical change, the substances involved retain their original properties. A new substance is not formed. A physical change can be reversed. Chemical changes happen on a molecular level when two or more substances chemically bond together.

Mending a broken bone  is a chemical change as to heal the bone enzymes are released which are chemicals.

Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.

There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.

There are three types of chemical changes:

1) inorganic changes

2)organic changes

3) biochemical changes

During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.

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Answer:

the answer to this question here is A

Explanation:

trust me

Answer:

Acid and Salt

Explanation:

Common hydrogen compounds

Hydrogen combines with other elements, forming a number of compounds, including common ones such as water (H2O), ammonia (NH3), methane (CH4), table sugar (C12H22O11), hydrogen peroxide (H2O2) and hydrochloric acid (HCl), according to Jefferson Lab.

Answer:

19.32 = moles of carbon

57.54 = moles of hydrogen

9.69 = moles of oxygen

Explanation:

232 g carbon × 1 mol C / 12.011 g C= 19.32 mol C

58 g hydrogen × 1 mol H / 1.008 g H = 57.54 mol H

155 g oxygen × 1 mol O / 15.999 g O = 9.69 mol O

Answer:

C2H2 + 5 O2 = 4 CO2 + 2 H2O

Add / Edited: 27.09.2014 / 25.01.2015

Evaluation of information: 5.0 out of 5 / number of votes: 2

Source: https://chemiday.com/en/reaction/3-1-0-339

Explanation:

Answer:

The energy change in a chemical reaction is due to the difference in the amounts of stored chemical energy between the products and the reactants. This stored chemical energy, or heat content, of the system is known as its enthalpy.

Explanation:

if u want to u can give me the crown btw have a good day

Answer:

here is what i put for this project:

The reaction in this project is exothermic. The energy change in a chemical reaction is due to the difference in the amounts of stored chemical energy between the products and the reactants. This stored chemical energy, or heat content, of the system is known as its enthalpy. The potential energy in reactants is higher than the potential energy of products in an exothermic reaction. Since energy is given off, the products are lower in energy than the reactants. The energy that is given off is a result of the formation of new bonds.

The change of the enthalpy happening in the chemical reaction is different from the pathway in between the initial and the final states. The addition of the equation gives the net change of the enthalpy. Enthalpy change is the amount of heat evolved or absorbed in the reaction under constant pressure. This can be calculated by checking the amount of heat evolved during the reaction. This reaction occurs at a constant pressure.

Answer:

1.584e10 = 15,840,000,000,000

Explanation:

250,000 miles

multiply the length value by 63360

25e4 x 63360

= 1.584e10

Answer: 110000000 inches

Explanation: Since the moon is 1,320,000,000ft away from the earth you divide 1,320,000,000ft  with 12 to get your final answer 110000000      

Answer:

purifying copper to produce copper wiring for homes

Explanation:

Answer:

b.purifying copper to produce copper wiring for homes

Explanation:

Answer:

Answer:

2,200 mL I believe it is.

Answer:

2,200 is the answer of your question

Answer:

D: fussion

Explanation:

The process called nuclear fussion.

for example, four hydrogen atoms combine in a nuclear fussion reaction to form one helium atom.

Answer:

Explanation:

The process is photosynthesis as plants need carbon dioxide and humans need oxygen so plants release oxygen which humans breath/take in and plant/trees take in carbon dioxide which humans release.

The natural process which removes  carbon dioxide from the atmosphere is photosynthesis.

It is defined as a process by which plants and other photosynthetic organisms convert the light energy in to chemical energy  through the process of cellular respiration.

Some of the energy which is converted  is stored in molecules of carbohydrates like sugar and starches  which are made up of from carbon dioxide and water . Photosynthetic organisms which can perform photosynthesis  are algae and cyanobacteria. Photosynthesis is largely responsible for producing and maintaining the content of oxygen in earth's atmosphere.

The process begins with proteins absorbing light energy  which are called reaction centers and contain a green pigment which is called chlorophyll . In plants ,these pigments are present inside organelles called chloroplasts while in bacteria they are present in plasma membrane.

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Answer:

hi

Explanation:

Answer:

Fleshy Fruits: All of most of the ovary wall (pericarp) is soft or fleshy at maturity. ... partitions, juicy seed vesicles, and a leathery exocarp similar to a hesperidium. ... This is a very common dry fruit found in many different plant families.

Explanation:

The special cases of gas laws and its description includes:

A. Boyle's law: P1 V1 = P2 V2

B. Charles's law: V/T = k or V1 / T1 = V2 / T2

C. Avogadro's law: V = kn

D. Dalton's law: Ptotal = P1 + P2 + P3 + .

Gas laws are laws that relate a gas's pressure, volume, and temperature. Boyle's law, named after Robert Boyle, states that the pressure P of a gas varies inversely with its volume V at constant temperature, or PV = k, where k is a constant. Charles' law is named after J. -A. -C.

They also include; Gay-Lussac's Law, Avogadro's Law and Dalton's law of partial pressures.

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Answer: The bold staircase in the periodic table allows us to classify which elements are metalloids.

Explanation: Additionally, it acts like a "divider" that allows us to properly distinguish the metals from the non-metals in the periodic table.

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Answer:

4

Explanation:

There are 4 different elements in the compound (N, H, P, O) but if you want to count the number of each element then the answer is different.

In NH4, theres 1 N and 4 H, but since there are 3 NH4s then u have 3 N and 12 H. There's 1 P and 4 Os as well.

Added together u have 3 + 12 + 1 + 4 = 20 elements in total.

hope this helps!

The car is not accelerating, because the car is driving at a constant speed of 20 miles per hour.

Answer:

I believe it's D. I searched up a lethal table chart and it states Aspirin is even more toxic than chlorine. As for the other two, it didn't specifically state it was toxic with one dose - meaning you have to take more than one dose for toxicity to take effect.

Explanation:

Answer:

Chemical change.

Explanation:

When it is heated it decomposes into mercury and oxygen gas. The mercury oxide reactant becomes the silver color of mercury. Hence, a color change can be noticed throughout the reaction.

Answer:

chemical change

Explanation:

Answer:

It increases.

Explanation:

I hope this helps.

Answer:

Increases

Explanation:

Hope this helps :)

Answer:

letter A.

Explanation:

the rate of a chemical reaction can be raised by increasing the surface area of a solid reactant. this is done by cutting the substance into small pieces, or by grinding it into a powder.if the surface area of a reactant is inceased: more particles are exposed to the other reactant.

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