Answer:the branch of science which examines the material of the universe and changes that these materials undergo
Chemistry deals with composition,structure,properties of matter and changes that these materials undergo
A balloon containing helium gas expands from 230 mL to 860 mL as more helium is added. What was the initial quantity of helium present if the expanded balloon contains 3.8 × 10-4 mol, assuming constant temperature and pressure? Which of the variables are known?
Answer and Explanation:
For computing the initial quantity of helium we have to apply the law of ideal gas which is shown below:
[tex]pV=nRT\[/tex]
[tex]n=\dfrac{pV}{RT}[/tex]
Now we have to compute the ratio between the initial and the final numbers of moles which is
[tex]\dfrac{n_1}{n_2}=\dfrac{\dfrac{p_1V_1}{RT_1}}{\dfrac{p_2V_2}{RT_2}}[/tex]
The statement defines that
[tex]T_1=T_2,~p_1=p_2.[/tex]
Therefore
[tex]\dfrac{n_1}{n_2}=\dfrac{V_1}{V_2}[/tex]
[tex]\dfrac{n_1}{3.8\times10^{-4}}=\dfrac{230}{860}\iff\\\\ n_1=\dfrac{3.8\times10^{-4}\times230}{860}[/tex]
[tex]\boxed{n_1\approx1.0\times10^{-4}~mol}[/tex]
And, the variables are known is starting volume and ending gas quantity
Answer:
beginning volume and ending quantity of gas
Explanation:
before the digestive system X-rayed people are required to swallow suspensions of barium sulphate (BaSO4). calculate the mass of one mole of BaSO4
Answer:
Molar mass of BaSO4 = 137.3 + 32 + (16 ×4)
= 137.3 + 32 +64
= 233.3g/mol
Molar mass = mass/ number of moles
= 233.3 g/mol = mass/ 1 mol
mass = 233.3g
Hope this helps.
Why would we want to correct for water vapor?
Answer:
The vapor pressure due to water in a sample can be corrected for in order to get the true value for the pressure of the gas.
Explanation:
The concentration of 1130+ in a solution is found to be 1.75 X 10-8 M 250C. Find [OH].
Answer:
[OH] = 6.31 * 10^-7 M
Explanation:
Mathematically;
pH + pOH = 14
Mathematically;
pH = -log [H3O+]
also;
pOH = -log [OH]
From the question; [H3O+] = 1.75 * 10^-8 M
pH = -log [1.75 * 10^-8]
pH = 7.76
since pH is normally given to 1 decimal place
we can say pH = 7.8
Now;
pH + pOH = 14
pOH = 14-7.8
pOH = 6.2
now pOH = -log [OH]
[OH] = -antilog 6.2
[OH] = 6.31 * 10^-7 M
the force that keeps the nucleons bound inside the nucleus of an atom
Answer:
Strong Nuclear Force
Explanation:
Strong Nuclear Force; is the force that keeps the nucleons bound inside the nucleus of an atom. It is a short range attractive force that acts between all nucleons in the nucleus of the atom that is much stronger than electrical forces.
Answer:
nuclear force
Explanation:
The graph below shows how the temperature and volume of a gas vary when the number of moles and the pressure of the gas are held constant. How can the volume of the gas be increased if the pressure is constant?
Answer:
Option C. By increasing the temperature
Explanation:
From the graphical illustration above, we see clearly that the volume and temperature of the gas are directly proportional. This implies that as the temperature increases, the volume will also increase and as the temperature decreases, the volume will also decrease. This can further be explained by using the ideal gas equation as shown below:
PV = nRT
P is the pressure.
V is the volume.
n is the number of mole.
R is the gas constant.
T is the temperature.
PV = nRT
Divide both side by P
V = nRT/P
Since n and P are constant, the equation above becomes:
V & T
V = KT
K is the constant.
The above equation i.e V = KT implies that:
As T increases, V will also increase and as T decreases, V will also decrease.
Considering the question given above,
The volume of the gas can be increased if the temperature is increased.
1.Mitch weighs out 67 grams of potassium (K) to make a buffer. How many moles of potassium did Dr. Hellman weigh out?
2.Which statement is NOT true about a reaction rate?
Group of answer choices
Increases with increase in reactant concentration
Increases with increasing temperature
Is the speed at which product is formed
Is the rate at which reactant is used up
All of the answers are true
3.Which statement is NOT true about a catalyst?
Group of answer choices
Are not used up during a reaction
Increases the rate of the reaction
Lowers the energy of activation
Biological catalysts are called enzymes
Are used up during a reaction
Answer:
1. 1.72 moles of potassium.
2. All of the answers are true
3. Are used up during a reaction
Explanation:
Recall that the number of moles is obtained from;
Number of moles= Mass of potassium/ molar mass of potassium
Mass of potassium= 67 g
Molar mass of potassium= 39 gmol-1
Number of moles of K= 67 g/ 39 gmol-1
Number of moles = 1.72 moles of potassium.
2. When we look at all the options, we will realize that all the options are true. The rate of reaction doubles for each 10°C rise in temperature, increasing reactant concentration increases particle collision and ultimately increases the rate of reaction. Rate of reaction deals with rate of disappearance of reactants or rate of appearance of products.
3. Catalysts remain unchanged in a chemical reaction because they do not actually participate in the reaction. Hence they are not used up in any chemical reaction.
I NEED HELP PLEASE, THANKS! :)
Combustion reactions are a notable source of carbon dioxide in the environment. Using the following balanced equation, how many grams of carbon dioxide are formed when 100.00 g of propane (C3H8) is burned? Express your answer to the correct number of significant figures.
Answer:
[tex]\large \boxed{\text{299.4 g}}[/tex]
Explanation:
We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.
Mᵣ: 44.10 44.01
C₃H₈ + 5O₂ ⟶ 3CO₂ + 4H₂O
m/g: 100.00
To solve a stoichiometry problem, you must
Use the molar mass to convert mass of C₃H₈ to moles of C₃H₈ Use the molar ratio to convert moles of C₃H₈ to moles of CO₂ Use the molar mass to convert moles of CO₂ to mass of CO₂
1. Moles of C₃H₈
[tex]\text{Moles of C$_{3}$H}_{8} = \text{100.00 g C$_{3}$H}_{8} \times \dfrac{\text{1 mol C$_{3}$H}_{8}}{\text{44.10 g C$_{3}$H}_{8}} = \text{2.268 mol C$_{3}$H}_{8}[/tex]
2. Moles of CO₂
The molar ratio is 3 mol CO₂:1 mol C₃H₈
[tex]\text{Moles of CO}_{2} = \text{2.268 mol C$_{3}$H}_{8} \times \dfrac{\text{3 mol CO}_{2}}{\text{1 mol C$_{3}$H}_{8}} = \text{6.803 mol CO}_{2}[/tex]
3. Mass of CO₂
[tex]\text{Mass of CO}_{2} = \text{6.803 mol CO}_{2} \times \dfrac{\text{44.01 g CO}_{2}}{\text{1 mol CO}_{2}} = \textbf{299.4 g CO}_{2}\\\text{The mass of CO$_{2}$ required is $\large \boxed{\textbf{299.4 g}}$}[/tex]
Answer:
Number of moles of propane:
=Mass in grams ÷ Relative molecular Mass
= 100/((12*3) + (1*8))
= 100 ÷ 44
= 2.2727
Mole ratio propane:carbon (IV) oxide = 1:3(from the equation)
Number of moles of CO2 = 3*2.2727 = 6.8181
Mass in grams = Relative molecular Mass * Number of moles
= 44 * 6.8181
= 299.9964 grams
Explanation:
the general formula for the alkane series is:
Answer:
The alkanes comprise a series of compounds that are composed of carbon and hydrogen atoms with single covalent bonds. This group of compounds comprises a homologous series with a general molecular formula of C n H 2 n+2 , where equals any integer.
Explanation:
The general formula for the alkane series is CnH2n+2
General formula for the alkane series:In this formula:
"Cn" shows how many carbon atoms are in the alkane molecule.
"H2n+2" shows the amount of hydrogen atoms in the alkane compound, with "n" being the number of carbon atoms.
Alkanes are a group of hydrocarbons that only have single bonds between their carbon atoms. The formula says that each carbon atom is connected to two hydrogen atoms. And the total number of hydrogen atoms in an alkane molecule is two more than double the number of carbon atoms.
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How to find the final temperature
Answer:
The final temperature will be "12.37°".
Explanation:
The given values are:
mass,
m = 0.125 kg
Initial temperature,
c = 22.0°C
Time,
Δt = 4.5 min
As we know,
⇒ [tex]q=mc \Delta t[/tex]
On putting the estimated values, we get
⇒ [tex]=0.125\times 22.0\times 4.5[/tex]
⇒ [tex]=12.37^{\circ}[/tex]
Give some examples of how ultraviolet rays can be used
Answer:
One of the most common ways of producing UV light is passing an electric current through vaporized mercury or some other gas. This type of lamp is commonly used in tanning booths and for disinfecting surfaces. The lamps are also used in black lights that cause fluorescent paints and dyes to glow.Explanation:
What does the pH of a solution measure?
O A. Color
O B. Volume
O c. Temperature
O D. Acidity
Answer:
D is the correct answer acidity
Explanation:
pH is the logarithmic measurement of the H3O+-concentration in water solutions.
By definition: pH = -log[H3O+]
Example: [H3O+] = 1.0*10-7 mol/L in neutral, pure water (at 25oC), so
pH = -log(H3O+) = -log(1.0*10-7) = 7.0
Someone please help me!!
Answer:
the 3rd one (0.01 cm the one selected already)
Explanation:
copper wire isn't excessively big, and it wraps around the pencil because its malleable. I think that the most accurate would be 0.01 cm
What does the VSEPR theory predict?
A. The chemical formula of a molecule
B. The size of a molecule
C. The shape of a molecule
D. The charge of a molecule
Answer: C
Explanation:
A P E X
The VSEPR theory predicts the shape and molecular geometry of the molecule.
What is molecular geometry?Molecular geometry can be defined as a three -dimensional arrangement of atoms which constitute the molecule.It includes parameters like bond length,bond angle and torsional angles.
It influences many properties of molecules like reactivity,polarity color,magnetism .The molecular geometry can be determined by various spectroscopic methods and diffraction methods , some of which are infrared,microwave and Raman spectroscopy.
They provide information about geometry by taking into considerations the vibrational and rotational absorbance of a substance.Neutron and electron diffraction techniques provide information about the distance between nuclei and electron density.
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What is the answer to this ?
Answer:
12.78 or 12.80 mostly like 12.78
Explanation:
Level 3- How is tooth decay related to pH?How can it be prevented?
Answer:
A lower pH of the mouth creates bad bacteria that eventually lead to decay of the tooth.
It can be prevented by avoiding food that causes acidity.
Explanation:
Tooth decay is caused by the pH level in the mouth dropping below 5.5, meaning it is acidic. It can be prevented by brushing your teeth as toothpaste is an alkali which will neutralise the pH level in your mouth.
Hope this helps
The nickname __________ was given to people from southern states that supported reconstruction laws that helped African Americans.
A. "copperhead"
B. "scalawag"
C. "carpetbagger"
D. "Radical Republican"
what is the net iconic charge of an oxygen ion?
The picture compound has which bond?
Answer:
There are C - C bonds and C - H bonds.
trust me! I took a test with this question and got 100! :)
Explanation:
Which statement best describes how an ionic bond forms?
The transfer of electrons forms strong bonds between ions.
The sharing of electrons forms strong bonds between ions.
The transfer of electrons results in attractive forces between molecules.
The sharing of electons results in attractive forces between molecules.
Answer:
The answer is option A
Explanation:
The question states,'which statement best describes how an ionic bond forms. The correct option is A. Ionic bonds are formed as a result of complete transfer of electrovalence electrons from one atom to another. The atom that donate the electron become a positively charged ion while the atom that received the atom become a negatively charged ion.
Brainliest is greatly appreciated
Answered by: Skylar
6/8/2020
10:05 AM (Eastern Time)
Answer:
A!!!!
Explanation:
Who was the second person to organize the elements on the periodic table and what property did he use to re-organize them?
Answer:
Dmitri Mendeleev
Explanation:
He was a Russian Scientist who decided to reorganize the periodic table after other notable scientists such as Antoine-Laurent Lavoisier had also tried to organize it based on the states of matter of the elements.
Mendeleev reorganized the period in the order of increasing atomic mass although there were some other modifications by modern scientists.
When naming acids, the term “hydro” is used then there are or are not (pick the correct one) any oxygens.
Answer:
There are no oxygen
Explanation:
Hydro is used when naming hydrogen compound and oxo is used when naming oxygen compound
what is the mass of 3.01x1023 atoms of iron(atomic mass of fe=56)
Answer:
N = n× l
N = number of entities
n= moles
l = Avogadro's constant = 6.023 × 10^23
3.01 × 10^ 23 = n * 6.023 × 10^23
n = 3.01 × 10^23/6.023 × 10^23
n= 0.5moles
Molar mass = mass/ number of moles
Molar mass = 56
mass = 56 × 0.5
= 28g
Hope this helps.
What is one way to make stored water safe?
Even though you asked for ONE WAY, I found some other good ways.
1. Thoroughly wash plastic soda bottles or milk jugs with warm, soapy water.
2. Store sealed containers in a dark, dry, and cool place.
3. If after six months you have not used the stored water, empty it from the containers and repeat steps 1 through 3 above.
a. 24.5 g of ammonia NH3 = how many moles of ammonia?
.b How many molecules of ammonia is that from 22.a.?
We know from the relative amounts of 16O and 18O that global temperatures and global climate have changed over time. Why is it important for scientists to be able to explain how they know that climate has changed over time and that they are able to repeat experiments that support this information?
Answer:
In order to take steps by humans for controlling the change in climate.
Explanation:
It is important that scientist find out the change which occurs in the climate with the passage of time by performing experiments and also repeat the experiments in order to verify their findings. Due to these experiments, scientists also find out the reasons behind of climate change which enable us to take steps in preventing the change that occurs in the environment. it is also important for scientists to be able to explain how they know that climate has changed over time in order to explain that he is not assuming or making predictions, he has to provide evidence for his statement which is only be possible through experiments.
When KCl dissolves in water
Answer:
They form K₂O (Potassium oxide) and HCl (Hydrochloric acid). This is because K and H are positively charged and O and Cl are negatively charged and cations only bond with anions.
How many moles of gas are contained in 22.41 liters at 101.325 kPa and 0ᴼC? (Note: use Ideal Gas Law, PV = nRT) a 2.5 mole b 1.5 mole c 1.0 mole d 2.0 mole
Answer:
Therefore, 1.00 mole of the gas is present in the container.
Explanation:
The following data were obtained from the question:
Volume (V) = 22.41L
Temperature (T) = 273K
Pressure (P) = 101.325 kPa
Gas constant (R) = 8.31 L.kPa/mol.K.
Number of mole (n) =...?
The number of mole of the gas in the container can obtained by applying the ideal gas equation as illustrated below:
PV = nRT
Divide both side by RT
n = PV /RT
n =101.325 x 22.41 / 8.31 x 273
n = 1.00 mole.
Therefore, 1.00 mole of the gas is present in the container.
Answer:
1 mole of gas is contained in 22.41 liters at 101.325 kPa and 0ᴼC
Explanation:
Ideal gases are a simplification of real gases that is done to study them more easily. It is considered to be formed by point particles, do not interact with each other and move randomly. It is also considered that the molecules of an ideal gas, in themselves, do not occupy any volume.
The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:
P*V = n*R*T
where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas.
In this case:
P= 101.325 kPa= 1 atmV= 22.41 Ln=?R= 0.082 [tex]\frac{atm*L}{mol*K}[/tex]T= 0°C= 273 °KReplacing:
1 atm*22.41 L=n* 0.082 [tex]\frac{atm*L}{mol*K}[/tex]*273 K
Solving:
[tex]n=\frac{1 atm*22.41 L}{0.082\frac{atm*L}{mol*K} *273 K}[/tex]
n=1 mole
1 mole of gas is contained in 22.41 liters at 101.325 kPa and 0ᴼC
find reducing and oxidizing agents
Answer:
SO4^2- is the oxidizing agent.
l^- is the reducing agent.
Explanation:
SO4^2- + I^- + H^+ —> H2S + I2 + H2O
To know which is the oxiding agent or the reducing agent, let us calculate the change in oxidation number of each element. This is illustrated below:
Note: the oxidation number of Hydrogen (H) is always +1 except in hydride where it is -1.
The oxidation number of Oxygen (O) is always -2 except in peroxide where it -1
For S:
SO4 = -2
S + 4O = -2
O = - 2
S =.?
S + (4 x -2) = -2
S - 8 = -2
Collect like terms
S = -2 + 8
S = +6
H2S = 0
2H + S = 0
H = +1
S =..?
2(1) + S = 0
2 + S = 0
Collect like terms
S = 0 - 2
S = -2
The oxidation number of S changes from +6 to -2
For I:
I = - 1
I = 0
The oxidation of I changes from -1 to 0.
Since the oxidation number of S changes from +6 to -2 i.e reduce, therefore SO4^2- is the oxidizing agent.
The oxidation number of I changes from -1 to 0 ie increased. Therefore, l^- is the reducing agent.
If the temperature outside is 297 what is this temperature in degrees celsius
Answer:
147.222 degrees C
Explanation:
assuming its 297 F it should be correct
The temperature outside is 297°F then this temperature in celsius is equal to 147.22 °C.
How to convert from Fahrenheit to celsius?Temperature can be described as a physical quantity that expresses quantitatively the perceptions of hotness or coldness. The most general scales are the Celsius scale with (°C), the Fahrenheit scale (°F), and the Kelvin scale (K), the latter being used predominantly for scientific purposes.
Fahrenheit to Celsius formula can be used to change the temperature from the scale Fahrenheit to degrees Celsius.
The formula that can be used to convert Fahrenheit to Celsius is given below:
[tex]\dusplaystyle ^oC = (^oF - 32) \times \frac{5}{9}[/tex]
Here, F represents the temperature in Fahrenheit, and C represents the temperature in Celsius.
Given the temperature in Fahrenheit = 297 °F
[tex]\dusplaystyle T( ^oC) = (297 - 32) \times \frac{5}{9}[/tex]
T = 147.22 °C
Therefore, the given temperature in celsius is equal to 147.22 °C.
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