how many hydrogen atoms are in one mole of caffeine

Answer:

A 1.0 g sample of propane, C3H8, was burned in the calorimeter.

The temperature rose from 28.5 0C to 32.0 0C and the heat of combustion 10.5 kJ/g.

Calculate the heat capacity of the calorimeter apparatus in kJ/0C

Explanation:

[tex]Heat of combustion = heat capacity of calorimeter * deltaT\\[/tex]

Given,

The heat of combustion = 10.5kJ/g.

[tex]deltaT = (32.0-28.5)^oC\\deltaT = 3.5^oC[/tex]

Substitute these values in the above formula to get the value of heat capacity of the calorimeter.

[tex]deltaT =heat capacity of calorimeter * (change in temperature)\\10.5kJ/g = heat capacity of calorimeter * (3.5^oC)\\\\=>heat capacity of calorimeter = \frac{10.5kJ/g}{3.5^oC} \\=>heat capacity of calorimeter = 3.0 kJ/g.^oC[/tex]

Answer:

The heat capacity of the calorimeter is [tex]3.0kJ/g.^oC.[/tex]

Answer:

1. 306,000: three significant figures because the last three zeros are not preceded by a decimal point.

2. 0.0073: two significant figures because the the leftmost zeros are not significant.

3. 39.9999: six significant figures because all these numbers are nonzero digits.

4. 25.00: four significant figures because right-handed zeros, after a decimal point, are significant.

5. 40,000,021: eight significant figures because intermediate zeros are significant.

6. 45,250.0: six significant figures because al the zeros are to the right of the nonzero digits.

7. 0.00011: two significant figures as well as #2.

8. 420.030700: nine significant figures because all the zeros are to the right of the first nonzero digits and after the decimal point.

Explanation:

Hello there!

In this case, by considering the given numbers, we can proceed as follows, by keeping in mind the rules for assigning significant figures:

1. 306,000: three significant figures because the last three zeros are not preceded by a decimal point.

2. 0.0073: two significant figures because the the leftmost zeros are not significant.

3. 39.9999: six significant figures because all these numbers are nonzero digits.

4. 25.00: four significant figures because right-handed zeros, after a decimal point, are significant.

5. 40,000,021: eight significant figures because intermediate zeros are significant.

6. 45,250.0: six significant figures because al the zeros are to the right of the nonzero digits.

7. 0.00011: two significant figures as well as #2.

8. 420.030700: nine significant figures because all the zeros are to the right of the first nonzero digits and after the decimal point.

Regards!

Answer: The value of i is 1.4 and 40% dissociation of 100 particles of zinc sulfate will yield 60 undissociated particles.

Explanation:

The equation used to calculate the Vant' Hoff factor in dissociation follows:

[tex]\alpha =\frac{i-1}{n-1}[/tex]

where,

[tex]\alpha [/tex] = degree of dissociation = 40% = 0.40

i = Vant' Hoff factor

n = number of ions dissociated = 2

Putting values in above equation, we get:

[tex]0.40=\frac{i-1}{2-1}\\\\0.40=i-1\\\\i=1.4[/tex]

The equation used to calculate the degee of dissociation follows:

[tex]\alpha =\frac{\text{Number of particles dissociated}}{\text{Total number of particles taken}}[/tex]

Total number of particles taken = 100

Degree of dissociation = 40% = 0.40

Putting values in above equation, we get:

[tex]0.40=\frac{\text{Number of particles dissociated}}{100}\\\\\text{Number of particles dissociated}=(0.40\times 100)=40[/tex]

This means that 40 particles are dissociated and 60 particles remain undissociated in the solution.

Hence, 40% dissociation of 100 particles of zinc sulfate will yield 60 undissociated particles.

Answer:

Identify each of the following as endothermic or exothermic.

a. Water in a pond evaporates.

b. Methane gas burns on a stovetop.

c. Water freezes to form ice.

d. Energy flows from the system to the surroundings.

e. Energy flows from the surroundings to the system.

Explanation:

An exothermic reaction is the one in which heat energy is released.

An endothermic reaction is one in which heat energy is absorbed.

a. Water in a pond evaporates.

This process absorbs heat energy.

Hence, this is an example of an endothermic process.

b. Methane gas burns on a stovetop and release heat energy and hence this is an example of an exothermic reaction.

c. Water freezes to form ice.

In this process heat energy is released.So this is an example of exothermic reaction.

d. Energy flows from the system to the surroundings.

That means heat energy is released into the surroundings.

So, this is an example of exothermic process.

e. Energy flows from the surroundings to the system.

That means energy is absorbed by the system.

So, it is an endothermic process.

Answer:

1) B

2) D

3) A

4) Ga

5) K

6)Po

7) Atomic size increases down the group

8) B<Al<Ga<In<Tl

9)Se<C<Ga

10) ionization energy is the energy required to remove electrons from the outermost shell of an atom.

Explanation:

In the periodic table, the properties of elements reoccur ''periodically'' throughout the table, hence the name 'periodic table'.

Ionization energy increases across the period hence the noble gas He has the highest ionization energy.

Since ionization energy increases across the period, group 1 elements possess the lowest ionization energy.

Since atomic size increases down the group and decreases across the period, gallium is smaller than indium, potassium is smaller than caesium, polonium is smaller than titanium and iodine is larger than bromine.

This explanation above justifies the order of increasing atomic radius of group 13 elements shown in answer number 8 above.

Since atomic size decreases across the period, the order of increasing atomic size shown in answer number 9 above is correct.

Ionization energy is the energy required to remove electrons from the outermost shell of an atom.

Answer:

1. B

2. A

3. C

4. C

5. D

Explanation:

Soil is regarded as the solid unconsolidated material of the earth crust. Soil is of three different types namely: Sandy soil, clay soil and loamy soil. These three different soil types possess different properties that distinguish them. Some of them are:

- CLAY soil is characterized as having the finest particles and can hold greater amount of water i.e. have a high water holding capacity.

- LOAMY SOIL is the best soil type for planting agricultural crops because it has the highest concentration of nutrients that suited for plant growth.

- loamy, Sandy and clay differ in how we feel when touched i.e. texture, and colour.

- SANDY soils are the kind of soils that are found in Sea shores and beaches.

- Soil is important to living things as it forms part of the earth where animals live, provides the necessary nutrients needed by plants, serves as a place where people live.

Explanation:

[tex]q = 350 \times0.897 \times (70 - 25) \\ q = 14127.75[/tex]

Answer:

Explanation:

As the measurements are given to us in centimeters, let's start by calculating the surface area in square centimeters:

Now we convert 100.75 cm² to m², as follows:

Finally we convert 0.010075 m² to nm², as follows:

Answer:

false

Explanation:

energy does not return to the sun, it returns to the plants or producers. if energy were to return to the sun, it would have to travel though space.

Answer:

2.5 × 10² ppm

Explanation:

Step 1: Given data

Step 2: Convert 0.050 g to μg

We will use the conversion factor 1 g = 10⁶ μg.

0.050 g × 10⁶ μg/1 g = 5.0 × 10⁴ μg

Step 3: Calculate the concentration of NaCl in ppm

The concentration of NaCl in ppm is equal to the micrograms of NaCl per gram of the sample.

5.0 × 10⁴ μg NaCl/200. g = 2.5 × 10² ppm

Answer:250 ppm

Explanation:

Explanation:

Aromatic nitrogen bonded to hydrogen, as found in pyrrole must be represented as [nH] ; thus imidazole is written in SMILES notation as n1c[nH]cc1 . When aromatic atoms are singly bonded to each other, such as in biphenyl, a single bond must be shown explicitly: c1ccccc1-c2ccccc2 .

Answer:

5.34275*10²³

Explanation:

Molar mass of O2 is 32g/mol

mass of the sample is 28.4g

number of moles = (mass of the sample) / (molar mass of O2)

=28.5g / 32g/mol

=0.8875mol

number of molecules = number of moles * Avogadro's Constant

= 0.8875 * (6.02*10²³)

= 5.34275 molecules

Answer:

A) Electrons orbit the nucleus in shells at fixed distances

Answer:

the answer is A

Explanation:

Answer:

Methanol and butanol are alcohols. Alcohols have the same_______________ as alkanes and the __________ identifies the compound as an alcohol.

Explanation:

Alcohols belong to a group of organic compounds which contain -OH group as the functional group.

So alcohols have the same carbon -hydrogen bonds as alkanes and the        -OH functional group identifies the compound as an alcohol.

Answer:

AgNO3 + KI → Agl + KNO3. Double-replacement reaction

Explanation:

Based on solubility rules, Silver, Ag produce an insoluble salt in presence of halides (Fluorides F-, Chlorides Cl-, Iodides, I-, and bromides Br-). That means the mixture of AgNO3 (Ag⁺ ions) with KI (I- ions) produce AgI as insoluble salt.

The reaction is:

And this is a double-replacement reaction where the cations exchange of anion to produce 2 new compounds.

Answer:

AgI + KNO3

Explanation:

double replacement

Answer:

Compound X has the formula C8H14.

X reacts with one molar equivalent of hydrogen in the presence of a palladium catalyst to form a mixture of cis- and trans-1,2-dimethyl cyclohexane. Treatment of X with ozone followed by zinc in aqueous acid gives a ketone plus formaldehyde (CH2=O). What is the structure of X?

Explanation:

The degree of unsaturation in the given molecule C8H14 is:

DU=(Cn+1)-Hn/2-Xn/2+Nn/2

where,

Cn=number of carbon atoms

Hn=number of hydrogen atoms

Xn=number of halogen atoms

Nn=number of nitrogen atoms

C8H14:

DU=(8+1)-14/2

=>DU=9-7 =2

Hence, the given molecule will have either two double bonds or one double bond and one ring or two rings.

X reacts with one molar equivalent of hydrogen in the presence of a palladium catalyst to form a mixture of cis- and trans-1,2-dimethylcyclohexane.

This indicates that the molecule X has one double bond and one ring that is cyclohexane ring.

Treatment of X with ozone follwed by zinc in aqueous acid gives a ketone plus formaldehyde (CH2=O).

So, the molecule has a ring and double bond CH2.

Based on the given data the structure of compound X is shown below:

The reaction sequence is shown below:

Answer:

37.85 L

Explanation:

3.785 x 10.00 = 37.85 L

it would take 37.85 L  to fill a 10.00 tank

(sorry if im wrong pls dont report)

(hope this helps can i plz have brainlist :D hehe)

Answer:

i didnt understand

Explanation:

Answer:

x = 2 (C₂H₆)

Explanation:

The general formula for alkanes is CₓH₂ₓ₊₂

2x + 2 = 6

Simply solve for n:

2x = 4

x = 2

Answer:

false all producers are at the top of food web

Answer:

[Ar] 4s²3d³

Explanation:

Vanadium has atomic number of 23. The electronic configuration of vanadium can be written as:

V (23) => 1s² 2s²2p⁶ 3s²3p⁶ 4s²3d³

NOTE: After the 18th electron, 4s will be filled before 3d.

We can also write the electronic configuration of an element in its condensed form by writing the symbol of the noble before the desired element in a squared bracket followed by the remaining electrons to complete the electronic configuration of the element.

The electronic configuration of vanadium in its condensed form is given below:

The noble gas before vanadium is Argon (Ar) with atomic number of 18. Thus, the electronic configuration of vanadium becomes:

V (23) => [Ar] 4s²3d³

Answer:

0.01684 s⁻¹

Explanation:

In a first-order reaction, the rate is proportional to the concentration of only one reactant (raised by 1). In this case, the reactant is H₂O₂. Thus, the rate law is the following:

rate = k [H₂O₂]

We have the following data for the initial rate:

rate = 0.00842 mol/(L·s)

[H₂O₂] = 0.500 mol/L

So, we introduce the data in the expression for the rate law to calculate k:

k = rate/[H₂O₂] = (0.00842 mol/L·s)/0.500 mol/L = 0.01684 s⁻¹

The correct answer is mixture

Answer:

25.46 mL

Explanation:

In a titration we use the volume and concentration of a solution to determine the previously unknown concentration of other solution. Let's consider the titration of an acid of unknown concentration with a standardized base (a base whose concentration we know). The generic neutralization reaction is:

HA + BOH ⇒ BA + H₂O

The base is in the buret and we will add it to the acid until the equivalence point is reached. The volume of base used is equal to the difference between the final reading of the buret and the initial reading of the buret.

V = 27.30 mL - 1.84 mL = 25.46 mL

Answer:

See explanation and image attached

Explanation:

The reaction between benzophenone and phenylmagnesium bromide is a Grignard reaction.

A Grignard reagent is any alkyl magnesium halide compound. In this case, the Grignard reagent is phenylmagnesium bromide.

Reaction of Grignard reagent with a ketone yields all alcohol. Thus, the reaction of benzophenone with phenylmagnesium bromide yields triphenyl methanol.

The mechanism of the reaction and all electron movements are shown in the image attached to this answer.

Answer:

See explanation

Explanation:

The electrophilic substitution of aromatic compounds occurs faster in substituted aromatic compounds due to the fact that the ring becomes more or less susceptible to electrophilic attack depending on the nature of the substituent in the ring.

Electron pushing substituents such as alkyl groups stabilize the positive charge developed during electrophilic substitution hence they activate the ring towards electrophilic substitution.

The methyl group is an ortho - para directing substituent hence the product obtained by nitration of toluene is o-nitrotoluene and p-nitrotoluene.

The stepwise mechanism for obtaining these products is shown in the image attached to this answer.

Answer:

Density = 19.3 g/cm³

Explanation:

In order to answer this question we need to keep in mind the following definition of density:

As both the mass and the volume are given by the problem, we can proceed to calculate the density of gold:

Answer:

25%

Explanation:

Cystic fibrosis is a recessive allele, meaning that the child must be aa to suffer the symptoms. Only 1/4 of the paired alleles is aa, so the probability of getting cystic fibrosis would be 25%.

Answer:

57.2 g

Explanation:

First we convert 66.4 grams of Ba(ClO₄)₂·3H₂O into moles, using its molar mass:

0.170 moles of Ba(ClO₄)₂·3H₂O would produce 0.170 moles of 0.170 moles of Ba(ClO₄)₂. Meaning we now convert 0.170 moles of Ba(ClO₄)₂ into grams, using the molar mass of Ba(ClO₄)₂:

Answer:

compound light microscope