How many miles will a person run a 400 km race?

Answer:

tru

Explanation:

Answer:

mole=mass/molarmass

Explanation:

molar mass of h2o=18

Answer: The enthalpy change for this reaction is, -803 kJ

Explanation:

The balanced chemical reaction is,

[tex]CH_4(g)+2O_2(g)\rightarrow CO_2(g)+2H_2O(g)[/tex]

The expression for enthalpy change is,

[tex]\Delta H=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)][/tex]

[tex]\Delta H=[(n_{CO_2}\times \Delta H_{CO_2})+(n_{H_2O}\times \Delta H_{H_2O})]-[(n_{O_2}\times \Delta H_{O_2})+(n_{CH_4}\times \Delta H_{CH_4})][/tex]

where,

n = number of moles  

Now put all the given values in this expression, we get

[tex]\Delta H=[(1\times -394)+(2\times -242]-[(2\times 0)+(1\times -75)][/tex]

[tex]\Delta H=-803kJ[/tex]

Therefore, the enthalpy change for combustion of methane is, -803 kJ

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:

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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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:

it's the third one

Explanation:

matter can't change, but mass can differ

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:

A. Na

Explanation:

Sodium is a good conductor of electricity and heat because it has only one electron in its valence shell.

i hope this helps :)

Answer:

C.) P

Explanation:

I believe this is correct, lmk if it's not.

Answer:

uhh its 497 miles

Explanation:

Answer:

Light bulb gives light energy which is usefull

Answer:

(c) light energy

Explanation:

As bulb is used for giving light and hence the energy that it gives is light energy.

Answer:

hshzjndbejkxn. znkskakannamzm msk

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!

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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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.

Explanation:

Mg + 2HNO2 → Mg(NO2)2 + H2

Answer:

Mg + 2HNO2 → Mg(NO2)2 + H2

Explanation:

Answer:

Answer:

It increases.

Explanation:

I hope this helps.

Answer:

Increases

Explanation:

Hope this helps :)

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:

4.54 * 10^-14 m

Explanation:

From Heisenberg's uncertainty principle, we can write;

Δp.Δx ≥ h/4π

Given that;

Δp =Δmv

So;

Δmv.Δx ≥h/4π

Δmv =2/100(3.5×10^7 m/s * 1.66 * 10^-27)

Δmv =1.162 * 10^-21 Kgms-1

Δx ≥6.63 * 10^-34 /4 * 3.142 * 1.162 * 10^-21

Δx ≥4.54 * 10^-14 m

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:

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:

2,200 mL I believe it is.

Answer:

2,200 is the answer of your question

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:

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:

what i need more details

Explanation:

Answer:

Ionic

Explanation:

AgNO3 is also highly soluble in water. Ionic means that the compound is composed of ions.