An unknown substance is obtained by police. The forensics laboratory has
determined it is made of nitrogen and oxygen. If 74.66 grams are nitrogen
and the police obtained a 250 gram sample, what is the percent
composition of oxygen in the sample?

Answers

Answer 1

Answer:

70.0 %

Explanation:

Step 1: Given data

Mass of nitrogen (mN): 74.66 gMass of the compound (mNxOy): 250 g

Step 2: Calculate the mass of oxygen (mO) in the compound

The mass of the compound is equal to the sum of the masses of the elements that form it.

mNxOy = mN + mO

mO = mNxOy - mN

mO = 250 g - 74.66 g = 175 g

Step 3: Determine the percent composition of oxygen in the sample

We will use the following expression.

%O = mO / mNxOy × 100%

%O = 175 g / 250 g × 100% = 70.0 %


Related Questions

a gas occupies a volume of 95 mL when the pressure is 400 mmHg .what volume does the gas occupy at 1200 mmhg if the temperature

Answers

Answer:31.7ml

Explanation:

Q1. Describe the term "Displacement reaction"

Answers

The reaction in which more reactive metal displaces the less reactive metal from its compound, is called as displacement reaction.
e.g., Fe+CuSO 4 →FeSO 4+Cu

How to solve this problem? I am stuck

Answers

The functional group of molecules as follows :

Molecule 1. is aldehyde and ketone, Molecule 2 is acid and thio, Molecule 3 is acid and amide, Molecule 4 is alcohol and ether, Molecule 5 is Alcohol and acid. The image attached below show the functional group and molecules are labeled.

What is polar compound ?

The polar compounds are those compound having different positive and negative charge, therefore the bonding with atoms such as nitrogen, oxygen, or sulfur.

A buffer is a solution the can control the pH change along with the addition of an acidic or basic substance. It is able to neutralize small amounts of added acid or base, So it maintains the pH of the solution. This is important to maintain pH ranges.

Thus, Molecule 1. is aldehyde and ketone, Molecule 2 is acid and thio, Molecule 3 is acid and amide, Molecule 4 is alcohol and ether, Molecule 5 is Alcohol and acid.

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Manganese is a transition metal. Consider the isotope: Mn-53. How many protons are in an atom of Mn-53 if the atom has a charge of 5?

Answers

Answer:

25

Explanation:

Isotopes of an element are the same element with different mass numbers but the same atomic number or the number of protons.

we know that in a balanced atom

Number of electrons = Number of protons = Atomic number

Atomic number (z) of manganese = 25

For Mn+5, the number of protons remains the same = 25

However, the number of electrons on Mn+5 = 21

Answer: 25

Explanation:

What is the best way to avoid bacterial contaminantion?

Answers

Answer:

Wash hands and surfaces often. Harmful bacteria can spread throughout the kitchen and get onto cutting boards, utensils, and counter tops. To prevent this: Wash hands with soap and hot water before and after handling food, and after using the bathroom, changing diapers; or handling pets.

Wash hands with soap and hot water before and after handling food, and after using the bathroom, changing diapers; or handling pets.

4.
Ethanol has a specific heat of 2.44 (J/g.°C). The temperature of 34.4 g of ethanol increases
from 25 °C to 78.8 °C. How much Heat was absorbed?

Answers

3.4C amount was absorbed

A 27 kg iron block initially at 375 C is quenched in an insulated tank that contains 130kg of water at 26 C. Assume the water that vaporizes during the process condenses back in the tank and the surroundings are at 12 C and 125 kPa. The specific heats of iron and water are 0.45 kJ/kgK and 4.18 kJ/kgK, respectively. a: Determine the final equilibrium temperature. b: Determine the entropy change of the combined system at the initial state. c: Determine the exergy of the combined system at the initial state. d: Determine the waste work potential during this process.

Answers

Solution :

a). Applying the energy balance,

[tex]$\Delta E_{sys}=E_{in}-E_{out}$[/tex]

[tex]$0=\Delta U$[/tex]

[tex]$0=(\Delta U)_{iron} + (\Delta U)_{water}$[/tex]

[tex]$0=[mc(T_f-T_i)_{iron}] + [mc(T_f-T_i)_{water}]$[/tex]

[tex]$0 = 27 \times 0.45 \times (T_f - 375) + 130 \times 4.18 \times (T_f-26)$[/tex]

[tex]$t_f=33.63^\circ C$[/tex]

b). The entropy change of iron.

[tex]$\Delta s_{iron} = mc \ln\left(\frac{T_f}{T_i} \right)$[/tex]

           [tex]$ = 27 \times 0.45\ \ln\left(\frac{33.63 + 273}{375 + 273} \right)$[/tex]

           = -9.09 kJ-K

Entropy change of water :

[tex]$\Delta s_{water} = mc \ \ln\left(\frac{T_f}{T_i} \right)$[/tex]

           [tex]$ = 130 \times 4.18\ \ln\left(\frac{33.63 + 273}{26 + 273} \right)$[/tex]

           = 10.76 kJ-K

So, the total entropy change during the process is :

[tex]$\Delta s_{tot} = \Delta s_{iron} + \Delta s_{water} $[/tex]

        = -9.09 + 10.76

         = 1.67 kJ-K

c). Exergy of the combined system at initial state,

[tex]$X=(U-U_{0}) - T_0(S-S_0)+P_0(V-V_0)$[/tex]

[tex]$X=mc (T-T_0) - T_0 \ mc \ \ln \left(\frac{T}{T_0} \right)+0$[/tex]

[tex]$X=mc\left((T-T_0)-T_0 \ ln \left(\frac{T}{T_0} \right)\right)$[/tex]

[tex]$X_{iron, i} = 27 \times 0.45\left(((375+273)-(12+273))-(12+273) \ln \frac{375+273}{12+273}\right)$[/tex]

[tex]$X_{iron, i} =63.94 \ kJ$[/tex]

[tex]$X_{water, i} = 130 \times 4.18\left(((26+273)-(12+273))-(12+273) \ln \frac{26+273}{12+273}\right)$[/tex]

[tex]$X_{water, i} =-13.22 \ kJ$[/tex]

Therefore, energy of the combined system at the initial state is

[tex]$X_{initial}=X_{iron,i} +X_{water, i}$[/tex]

            = 63.94 -13.22

            = 50.72 kJ

Similarly, Exergy of the combined system at initial state,

[tex]$X=(U_f-U_{0}) - T_0(S_f-S_0)+P_0(V_f-V_0)$[/tex]

[tex]$X=mc\left((T_f-T_0)-T_0 \ ln \left(\frac{T_f}{T_0} \right)\right)$[/tex]

[tex]$X_{iron, f} = 27 \times 0.45\left(((33.63+273)-(12+273))-(12+273) \ln \frac{33.63+273}{12+273}\right)$[/tex]

[tex]$X_{iron, f} = 216.39 \ kJ$[/tex]

[tex]$X_{water, f} = 130 \times 4.18\left(((33.63+273)-(12+273))-(12+273) \ln \frac{33.63+273}{12+273}\right)$[/tex]

[tex]$X_{water, f} =-9677.95\ kJ$[/tex]

Thus, energy or the combined system at the final state is :

[tex]$X_{final}=X_{iron,f} +X_{water, f$[/tex]

            = 216.39 - 9677.95

            = -9461.56 kJ

d). The wasted work

[tex]$X_{in} - X_{out}-X_{destroyed} = \Delta X_{sys}$[/tex]

[tex]$0-X_{destroyed} = $[/tex]

[tex]$X_{destroyed} = X_{initial} - X_{final}$[/tex]

                = 50.72 + 9461.56

                = 9512.22 kJ

matching will give brainliest. if you can answer any it help
1. element with atomic number greater than 92.
2. helium nucleus with and atomic number or 2 and a mass of 4.
3. unit for measuring exposure to radiation.
4. changing of one element to another due to alpha or beta decay.
5. caused by the decay of an electron.
6. atoms of the same element with different numbers of neutron.
7. the initial isotope before decay.

a. rem
b. alpha particle
c. beta particle
d. trans uranium element
e. transmutation
f. isotope
g. parent nuclide

Answers

Explanation:

In natural radioactive decay, three common emissions occur. When these emissions were originally observed, scientists were unable to identify them as some already known particles and so named them:

alpha particles ( α )

beta particles (β)

gamma rays (γ)

These particles were named using the first three letters of the Greek alphabet. Some later time, alpha particles were identified as helium-4 nuclei, beta particles were identified as electrons, and gamma rays as a form of electromagnetic radiation like x-rays, except much higher in energy and even more dangerous to living systems.

HELP PLEASEUse the molar volume of a gas at SATP to determine the
following values at SATP:
(a) the amount of nitrogen in 44.8 L of pure gas
(b) the volume (in litres) of 4.8 mol of propane gas, C3H,(g)
(c) the mass of carbon dioxide in 34.6 L of carbon dioxide
gas, CO₂(g)
(d) the volume (in mL) of 1250 g of methane, CH₂(g)
(e) the amount of oxygen in 36.5 L of 02 gas

Answers

The most common example is the molar volume of a gas at standard temperature and pressure (STP), which is equal to 22.4 L for 1 mole of any ideal gas at 273.15 K and 1 atm of pressure.

What are the applications of the Ideal Gas Law- Molar Volume?

Stoichiometry refers to the quantitative relationship between reactants and products. Calculating the quantities of reactants needed to make a given quantity of products, or the quantities of products resulting from a given quantity of reactants, is required in stoichiometric problems. Gas laws must be taken into account for the calculation if one or more reactants or products in a chemical reaction are gases. The findings of ideal gas law applications are often accurate to within 5%. We go over a few key ideas that are crucial for solving Stoichiometry Problems involving Gases in the sections below.

Stoichiometry and gas laws both rely on the mole notion as their foundation. A mole is an exact measurement of a substance. Based on the quantity of identities, a mole is a unit (i.e. atoms, molecules, ions, or particles). The number of identities in a mole of anything is equal to the number of atoms in exactly 12 grams of carbon-12, the most common isotope of carbon.

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Atoms bond by ______ electrons.
O gaining
O sharing
O losing
O all of the above

Answers

The answer is all of the above. Hope this helps.

Students performed an investigation on how aluminum cans taken to a recyle center were able to be reused. They found out an aluminum can undergoes which type of change?

a physical change because the can is heated
a chemical change because new metal is formed
a physical change because the material remains the same
a chemical change because an old can is changed into a new can

Answers

Answer:

The correct answer is - a physical change because the material remains the same.

Explanation:

A chemical change is the change that results in the formation of the new element or the substance whereas the physical change remains the same material or substance even after the change.

The physical change can be a change in density, size, shape, or volume, and other properties. In the recycling of the aluminum can the material remain the same only shape or size of the aluminum change order to reuse.

Answer:

its D i promise

Explanation:

the bond between br atoms in a br2 molecule is

Answers

Answer:

COVALENT

Explanation:

covalent and is formed by the sharing of two valence electrons.

Calculate the molecular weight of chalk.Step by step​

Answers

Answer:

100 g/mol

Explanation:

The chemical formula of chalk is CaCO3

So

1x Ca =40

1x C = 12

Ox 3 = 16

Meaning it has a molar mass of 100

I need help with this​

Answers

Answer:

the answer is the last one , sorry if im wrong.

Explanation:


The graph represents the amount of energy in the
reactants and products of a chemical reaction.
If total energy is conserved, which statement
explains why the energy of the reactants does not
equal the energy of the products?
Energy
Energy of Energy of
Reactants Products
A.
The reaction is exothermic
B. The reaction is endothermic.
C. The reaction requires a catalyst.
D
The reaction has a low activation energy.

Answers

Answer: The correct answer is in an exothermic reaction the energy of the product is less than the energy of the reactants.

Explanation: got it

The energy of reactants is not equal to that of products as the reaction is an exothermic reaction.

What is an exothermic reaction?

An exothermic reaction is defined as a chemical reaction which involves release of energy in the form of light,heat .In these reactions, energy is transferred from system to surroundings rather than taking energy from surroundings into system as in endothermic reactions.

In an exothermic reaction,change in enthalpy is negative.Therefore, it can be inferred that net amount of energy which is required to start the exothermic reaction is less than the net amount which is released by the reaction.

Examples of exothermic reactions are combustion reactions, detonation of nitroglycerin , neutralization reactions and nuclear fission.

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А
A and B are forces acting on a falling object. Which
force, A or B, represents gravity in the diagram?
Force 1
is gravity because it attracts the ball
to the ground.
B
Ground

Answers

Answer:

Force B

Explanation:

Gravity pulls "down"  :D

Hoped this helped!

Have a nice day!

At 25.0° C, a 10.00 L vessel is filled with 5.25 moles of Gas A and 7.75 moles of Gas B. What is the total pressure in atm?

Answers

Answer:

23.12 atm

Explanation:

First, add together the moles of the two samples:

5.25 moles + 4.20 moles = 9.45 moles

273 + 25 = 298 K for the temperature

volume is 10.0 L

Since we have moles now, we have to rearrange our ideal law equation to solve for pressure:

[tex]P = \frac{nRT}{V}[/tex]

[tex]\frac{(9.45 moles) X (0.08206) X (298 K)}{10.0 L}[/tex]

9.45 X .08206 X 298 all divided by 10.0 = 23.09202 atm (or 23.12)


The following statements are either true or false. Read each sentences carefully, then write TRUE faLSE
1. A force cannot be seen
2. A force cannot be felt.
3. A force always causes things to move
When an object is at rest, no gravitational force is acting on it
5 Gravitational force pulls all things downward
5. Mass and weight are the same quantities
7. All objects on Earth have weight
8 Some forces are useful to people
9. Gravity makes it easy for a person to ride a bicycle up
10. Weight is measured in grams (R) and kilograms​

Answers

1) T

2) F

3) F

4) F

5) T

6) F

7) T

8) T

9) F

10) ...T... grams are usually in lowercase g

why does water wet glass and not mercury​

Answers

Mercury probably isn’t as adhesive as water

0.0075mole of calcium trioxocrabonate IV is added to 0.015mole of a solution of hydrochloric acid .the volume of gas evolved at stp is​

Answers

Answer:

1mole of gas at STP = 22.4dm3

0.0075 mole of CaCO3 = xdm3

cross multiply;

where 22.4dm3 = 22400cm3

x * 1 = 0.0075 * 22400 → 168cm3

the gas CO2 which evolved was gotten from CaCO3 so we use the number of moles of CaCO3 only

Explain how abiotic factors change within a community as a result of the
succession of vegetation.

Answers

Couldn’t figure out the answer hope you get it soon

Q)A certain mass of gas occupies a volume 2.5 L at 90atm. What pressure would the gas exert if it were placed in a 10 L container at the same temperatur?​

Answers

Answer:

23 atm

Explanation:

Step 1: Given data

Initial volume (V₁): 2.5 LInitial pressure (P₁): 90 atmFinal volume (V₂): 10 LFinal pressure (P₂): ?

Step 2: Calculate the final pressure of the gas

If we assume constant temperature and ideal behavior, we can calculate the final pressure of the gas using Boyle's law.

P₁ × V₁ = P₂ × V₂

P₂ = P₁ × V₁ / V₂

P₂ = 90 atm × 2.5 L / 10 L = 23 atm

As expected, since the volume increased, the pressure decreased.

Why Zinc is not really considered as member of the transition metals?

Answers

The definition of a transition metal is that it must have an incompleted sub-level in one or more of its oxidation states. As zinc has a completed sub-level at all oxidative states, so it can't be considered a transition metal.

What is the [H+] if [OH-] = 1 x 10-5 M?

Answers

Its b
Because kw= (H+ )x (oH-)

Le Châtelier’s principle is applied in the bottling of carbonated soft drinks. You are probably familiar with the “hissing” or “popping” sound of opening of either an aluminum soda can or plastic bottle. This occurs by adding carbon dioxide to water to produce carbonic acid in a reversible reaction, which is shown below: H2O(l) + CO2(g) <-------------------> H2CO3(aq) As you may have known, these beverages are bottled under increased pressure, placing stress on the equilibrium. Following Le Châtelier’s principle, the system shifts to the right to reduce the stress, in response to the increase in pressure. When the bottle or can is opened, the pressure is reduced. This reaction favors the reactants, thus shifting the system to the left, and CO2 gas forms and comes out of the solution. Question # 8 :You open a can of Coca-Cola and you pour it into a glass with ice. You notice that the soda is very fizzy and quite effervescent. What do you think is responsible for this? Group of answer choices A. H2O formation under pressure. D. Release of H2O as a result of opening the can. B. H2CO3 formation under pressure. C. Release of CO2 as a result of opening the can.

Answers

Answer:

C. Release CO2 due to can opening

Explanation:

Le Châtelier’s principle states that when a reaction is at equillibrium and it is disturbed it will respond to return to equilibrium.

SO

H2O(l) + CO2(g) <-------------------> H2CO3(aq)

When you open a bottle of coke it is under pressure and not at equillibrium so it reacts by releasing the gas to reach equilibrium it can be seen in the equation above just that this is for club soda not coke, the idea applies though

Neera and Tom dissolved different masses of salt in 500 cm³ of water.
They measured the temperature at which each salt solution boiled.
salt
solution
(They wrote down the variables that might affect the investigation.
temperature of the
mass of salt
laboratory
dissolved in water
boiling point of
salt solution
thermometer
volume of water
starting temperature
of the water
type of salt used

Answers

The variables that might affect the investigation while dissolving different masses of salt are temperature and mass of the salt.

In the provided investigation, what are the independent and dependent variables?

A variable that changed during the inquiry is regarded as an independent variable and is called "mass of salt dissolved in water." While the investigation's dependent variable, "boiling point of salt solution," is a variable that was monitored.

What are variables in a laboratory?

There are numerous things that can be changed to see how they affect other things. Variables are the changeable quantities. Any element, character trait, or condition that can exist in a variety of forms or concentrations is a variable. Independent, dependent, and controlled variables are the three types of variables that often make up an experiment.

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Neera and Tom dissolved different masses of salt in 500 cm3 of water.

They measured the temperature at which each salt solution boiled.

(a) They wrote down the variables that might affect the investigation.

temperature of the laboratorymass of salt dissolved in waterstarting temperature of the waterboiling point of salt solutionvolume of watertype of salt used

(i) What is the independent variable (the variable they changed) in

their investigation?

(ii) What is the dependent variable (the variable they measured) in

their investigation?

(iii) Which variable above would affect the experiment the least?

Pls help with question a and b.

Answers

a) 1 - Trigonal planar 2 - Trigonal planar

b) 1- Linear  2 - Tetrahedral  3 - Tetrahedral

c) 1 - Trigonal planar 2 - Tetrahedral

What are the shapes?

We have to know that the shapes at the various carbon atoms and other atoms would depend on the number of the electron pairs and the hybridization of the atom.

We must have to note that the shape of the atom can be found on the basis of the valence shell electron pair repulsion theory which deals with the arrangement of that electrons around the outermost shell of the central atom.

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1. What is the modern view of electrons in the quantum mechanical model?

Answers

Answer: An electron con only exist in a limited number of quantized energy levels.

Explanation:

A gas occupies 12.5 ft at - 173 °C. At what Celsius temperature will its volume be 16.0
it? Assume that pressure remains constant

Answers

Answer:

T₂ = 128.19 K

Explanation:

Given that,

The initial volume, V₁ = 12.5 ft³

Initial temperature, T₁ = -173 °C = 100.15 K

Final volume, V₂ = 16 ft³

We need to find the new temperature. The relation between temperature and volume is given by :

[tex]V\propto T\\\\\dfrac{V_1}{V_2}=\dfrac{T_1}{T_2}[/tex]

Put all the values,

[tex]T_2=\dfrac{T_1V_2}{V_1}\\\\T_2=\dfrac{100.15\times 16}{12.5}\\\\T_2=128.19\ K[/tex]

So, the new temperature is 128.19 K.

A 6.8 L sample of gas is collected at a pressure of 0.91 atm. What will the Volume of the gas occupy at 1.0 atm if the temperature remains constant?

Answers

Answer:

Explanation:

V1*P1= V2*P2

6.8L*0.91atm=1.0atm*x

x=6.188 L

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