The final temperature of a mixture of 100g of water at 20°C and 50g of water at 50°C is 30°C.
What is the principle of method of mixtures ?
The amount of heat lost by the hotter sample = The amount of heat gained by the cooler water sample
The amount of heat gained by the cooler water sample is: -
Q1₁= m₁c(T – T₁)
The amount of heat lost by the hotter water sample is: -
Q₂ = m₂c(T₂ - T)
Q₁ = Q₂
m₁c(T – T₁) = m₂c(T₂ - T)
T = (m₁T₁ + m₂T₂)/(m₁+ m₂)
Let the final temperature of the mixture of 100g of water at 20°C and 50g of water at 50°C be T.
m₁ = 100g
T₁ = 20°C
m₂ = 50g
T₂ = 50°C
The final temperature of water = (100*20+50*50)/(100+50)
= (2000+2500)/(150)
=4500/150
=30°C
Therefore , the final temperature of a mixture of 100g of water at 20°C and 50g of water at 50°C is 30°C.
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Classify the following as an element, compound, homogeneous mixture, or heterogeneous
Mixture :
Iron and rust
A. Element
B. Compound
C. Homogenous mixture
D. Heterogenous mixture
Answer:
It's an homogeneous Mixture
hehe
Most scientists recommend reducing carbon dioxide emissions. Less carbon dioxide in the atmosphere would be expected to?
Answer:
the air would be much cleaner and better for us to breath.
Explanation:
Define Acid dissociation constant constant
Answer:
An acid dissociation constant, K a, (also known as acidity constant, or acid-ionization constant) is a quantitative measure of the strength of an acid in solution. It is the equilibrium constant for a chemical reaction ↽ − − ⇀ − + + known as dissociation in the context of acid–base reactions.
Explanation:
ASAP plz I will give the brainliest
Which type of bond describes the coming
together and sharing of two unpaired outer
electrons, one from each atom?
a. Single covalent bond
b. Double covalent bond
С. Triple covalent bond
d. lonic bond
2nd question
What is the name of this molecule (CO2) that
forms by burning of fuels and is one of the
gases that contributes to global
warming/climate change?
A. Carbon oxygen
B. Carbon and two oxygen
C. Carbon dioxide
D. Carbon oxide
Answer:
Question 1
Which type of bond describes the coming together and sharing of two unpaired outer electrons, one from each atom?
A. Single covalent bond.
Definition of single covalent bond:
A single covalent bond is when only one pair of electrons is shared between atoms.
Question 2
What is the name of this molecule (CO2) that forms by burning of fuels and is one of the gases that contributes to global warming/climate change?
C. Carbon dioxide.
A compound contains 57.2 percent carbon, 6.1 percent hydrogen, 9.5 percent nitrogen, and 27.2 percent oxygen. What the empirical formula of the compound?
Answer:
So the empirical formula is C14H18N2O5
Explanation:
C = 57.2% = 12g/mol
H = 6.1% = 1g/mol
N = 9.5% = 14g/mol
O = 27.2% = 16g/mol
Empirical Formula for compound hmm
Assume
C = 57.2g
H = 6.1g
N = 9.5g
O = 27.2g
So we have
C = 57.2g/12g = 4.76 moles
H = 6.1g/1g = 6.10 moles
N = 9.5g/14g = 0.68 moles
O = 27.2g/16g = 1.70 moles
Divide each mole value by the smallest number of moles calculated. Round to the nearest whole number.
C = 4.76 moles / 0.68 moles = 7
H = 6.10 moles / 0.68 moles = 9
N = 0.68 moles / 0.68 moles = 1
O = 1.70 moles / 0.68 moles = 2.5
Ok so we now have the ratios but for O it's 2.5, have to be whole numbers so we will need to double all the numbers.
C = 14
H = 18
N = 2
O = 5
So the empirical formula is C14H18N2O5
what happens to the grass molecules when it is eaten by the zebra?
Answer:
read below
Explanation:
When the zebra eats grass, it gets energy from the sun that has been stored in the grass. Similarly, the lion obtains energy stored in the zebra. The zebra and lion both obtain the sun's energy indirectly from the energy that the grass obtained through photosynthesis.
Answer/Explanation:
It gets energy from the sun that was inside of the grass.
It happens like this:
Sun gives energy to grass, grass gives energy to zebra.
Sun ---> Grass ---> Zebra
If two electrically charged objects repel one another, which statement must be true? One object has more electrons, and the other has more protons. Electrons will flow from one object to the other when they touch each other. The two objects have the same electric charge. The objects do not have strong electrical fields.
Answer:
The two objects have the same electric charge.
Explanation:
Electrically charged objects repel if they are both of the same charge, ie plus plus or minus minus.
The statement, that describes two electrically charged objects repel one another is "the two objects have the same electric charge."
What is an electric charge?The feature of subatomic particles that causes them to experience a force when put in an electric and magnetic field is known as electric charge.
When one or more items are electrically charged, electrostatic interactions are widespread. Two items with opposing charges will attract each other.
Unlike the attractive force between two items with opposite charges, two objects with like charges repel each other. In other words, a positively charged object will repel another positively charged object. This repelling force will separate the two items.
Hence the correct answer is the two objects have the same electric charge.
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Please I need this answer quick I will give brainliest
A student decreases the temperature of a 417 cm³ balloon from 278 K to 231 K.
Assuming constant pressure, what should the new volume of the balloon be?
376 cm³
417 cm³
462 cm³
924 cm³
Answer:
The new volume of the balloon is [tex]346.5\ cm^3[/tex].
Explanation:
Initial volume of a balloon is 417 cm³
The temperature decreases from 278 K to 231 K.
It is required to find the new volume of the balloon if the pressure is constant pressure. At constant pressure, volume is directly proportional to the temperature. So,
[tex]V\propto T[/tex]
i.e.
[tex]\dfrac{V_1}{V_2}=\dfrac{T_1}{T_2}[/tex]
V₂ is final volume.
[tex]V_2=\dfrac{V_1T_2}{T_1}\\\\V_2=\dfrac{417\times 231}{278}\\\\V_2=346.5\ cm^3[/tex]
So, the new volume of the balloon is [tex]346.5\ cm^3[/tex].
4) A 4.00 L balloon is filled with 0.297 moles of helium gas with a pressure
of 0.910 atm. Calculate the temperature, in Kelvin, of the gas. (KEEP 3 SIG
FIGS; DO NOT TYPE ANY UNITS)*
Answer: 149
Explanation:
Using the ideal gas equation; PV = nRT
P= Pressure = 0.910 atm, T= Temperature = ?
V= Volume = 4.0L R = Gas constant = 0.08206 L.atm/mol/K
n = number of moles = 0.297
Making 'T' the subject of the formular, we have;
T = P V/ n R = 0.910 x 4 / 0.297 x 0.08206
= 149
PLEASE HELP ASAP!!!! 15PTS
How are 2,2-butanediol and 2,3,4-pentanetriol similar? Pick two.
EXPLANATION
2,2-butanediol is a four carbon chain with two hydroxyl groups both on the second carbon. 2,3,4-pentanetriol is a five carbon chain with three hydroxyl groups; one on carbon 2,3 and 4.
SELECT ALL THAT APPLY
Neither contain a hydroxyl group on an end chain carbon.
Neither contain four carbons in the parent chain.
Both contain a hydroxyl group on the second carbon.
Answer:
Both contain a hydroxyl group on the second carbon.
Neither contain a hydroxyl group on an end chain carbon.
Explanation:
2,2-butanediol Formula: C4H10O2
2,3,4-pentanetriol Formula: C5H12O3
Both contain a hydroxyl group on the second carbon.
Neither contain a hydroxyl group on an end chain carbon.
Which of the following is true for the theoretical yield of a reaction? (1 point) a It is always calculated as a ratio. b It is the yield from the excess reactant. c It is the yield from the limiting reactant. d It is always twice the value of the actual yield.
Answer:
It is calcualted based ion the yield from the limiting reactant
Explanation:
What types of substances are considered drugs?
Answer:
Marijuana
Opiates
Opioids
Explanation:
What are the units of measurement for atomic radius?
Answer:
Units used to measure atomic radius:
Angstroms (Å): This the most common unit used. Equivalent to 1.0 x 10-10 meters.
Nanometer (nm): Equivalent to 1.0 x 10-9 meters.
Picometer (pm): Equivalent to 1.0 x 10-12 meters.
Balance the following chemical
equation by providing the correct
coefficients.
_FeBr3 +_Na2S -> _Fe2S3 + _NaBr
Answer:
2FeBr3 + 3Na2S ➡️ Fe2S3 + 6NaBr
It is important for _______ to participate in conservation efforts. a. government b. business c. citizens d. all of the above Please select the best answer from the choices provided A B C D
Answer:
D
Explanation: government
business
citizens
The correct answer is option d all of the above.
What are the conservation efforts?Conservation refers to the preservation and care of these resources for future generations. It entails preserving species variety, DNA, and ecosystems, as well as environmental services like nitrogen cycling.Learn more about conservation efforts are:-
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which of the following is a basic salt solution?
A. NH3 (aq)
B. NH4I (aq)
C. KNO3 (aq)
D. Na2CO3 (aq)
Answer:
D. Na2CO3
Explanation:
I'm just guessing tbh
A skeleton chemical equation includes which of the following
Answer:
Explanation:
Skeleton equations are also known as unbalanced equations.
Eg I react Oxygen, Hydrogen and Chlorine and I get Water and Chlorine Gas
H2 + Cl2 = HCl
Left Side
H = 2
Cl = 2
Right Side
H = 1
Cl = 1
As you can see it's not balanced is skeleton equation.
Please help me out on this question!!
Answer:
Water H2O
Explanation:
A solvent is defined as being able to dissolve other substances, the fertilizer is being dissolved in the water prior to watering the plants, therefore the water is the solvent in this case.
In a reaction, 25 grams of reactant
AB breaks down into 10 grams of
product A and an unknown amount
of product B. Using the law of conservation of mass, how much does product B weigh?
a. 25 g
B. 10 g
С. It cannot be determined from the given
information.
d
D. 15g
Answer:
D. 15g
Explanation:
The law of conservation of mass states that, in a chemical reaction, mass can neither be created nor destroyed. This means that the amount of matter in the elements of the reactants must be equal to the amount in the resulting products.
In this question, 25 grams of a reactant AB, was broken down in a reaction to produce 10 grams of products A and X grams of product B. According to the law of conservation of mass, the mass of the reactant must be equal to the total mass of the products. This means that 25 grams must also be the total mass of both products in this reaction. Hence, if product A is 10 grams, product B will be 25 grams - 10 grams = 15 grams.
Therefore, product B must be 15 grams in order to form a total of 25 grams when added to the mass of product A. This will equate the mass of the reactant AB and fulfill the law of conservation of mass.
In The diagram which part is negatively charged?
• solid Cu
• wire
• salt bridge
• solid Zn
Answer:
Solid Zn
Explanation:
I took the test :-)
In the diagram solid Zn is negatively charged.
When is solid Zn is negatively charged?Zinc is known as a element that acts as a negative electrode based on the fact that it has more negative potential and acts as the anode.
Based on the fact that zinc is a metal, it is known to often forms metallic compounds with other kinds of metals and based on the fact that it also has an ion charge of +2, the zinc ions are referred to as a strong reducing agents and thus do form ionic bonds.
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At a party, you see someone on the floor with grayish skin, having
trouble breathing. This could be a sign of:
AN ALCOHOL OVERDOSE
AN OPIOID OR DEPRESSANT OVERDOSE
A STIMULANT OVERDOSE
ALL OF THE ABOVE
A person having trouble breathing could be a sign of
d. All of the above(alcohol overdose, depressant overdose, or stimulant overdose)
Causes of trouble breathing:Most instances of windedness are because of heart or lung conditions. These organs are engaged with shipping oxygen to your tissues and removing carbon dioxide, and issues with both of these cycles influence your relaxation.
At a party, if a person feels trouble breathing then it can be due to an alcohol overdose, depressant overdose, or stimulant overdose.
Thus, option D is correct.
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A chemist prepares a solution of iron(III) bromide (FeBr3) by measuring out 41.1 mg of FeBr3 into a 50. mL volumetric flask and filling to the mark with
distilled water.
Calculate the molarity of Br- anions in the chemist's solution
Be sure your answer is rounded to 2 significant digits.
Answer: The molarity of [tex]Br^-[/tex] anions in the chemist's solution is 0.0084 M
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.
[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]
where,
n = moles of solute
[tex]V_s[/tex] = volume of solution in ml
moles of [tex]FeBr_3[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{0.0411g}{295.6g/mol}=0.00014mol[/tex]
Now put all the given values in the formula of molality, we get
[tex]Molarity=\frac{0.00014\times 1000}{50}=0.0028[/tex]
As 1 mole of [tex]FeBr_3[/tex] gives = 3 moles of [tex]Br^-[/tex]
0.0028 moles of [tex]FeBr_3[/tex] gives = [tex]\frac{3}{1}\times 0.0028=0.0084 moles[/tex] of [tex]Br^-[/tex]
Thus the molarity of [tex]Br^-[/tex] anions in the chemist's solution is 0.0084 M
Find the Empirical formula for 0.765g Cr, 0.235g O
Answer:
CrO
Explanation:
0.765g Cr
0.235g O
O = 16g/mol
Cr = 52g/mol
O 2-
Cr 2+, 3+, 6+
0.765 + 0.235 = 1
so 76.5% Cr
23.5% O
76.5/52 = 1.47/1.47 = 1
23.5/16 = 1.47/1.47 = 1
CrO
Rice has a bulk density of 0.9 g/mL, but an individual grain of rice has a
density of 1.1 g/mL. Water has a density of 1.0 g/mL. What would happen to
a cup of rice when poured into a pot of water?
Answer:
Individual grain of rice will sink.
Explanation:
Given:
Rice bulk density = 0.9 g/ml,
Individual grain of rice density = 1.1 g/ml
Water density = 1.0 g/ml
Find:
What happens with a cup of rice when poured into water =?
Explanation:
Each piece of grains of rice will sink into the water because individual grains of rice has a higher density than water.
For the reaction NH4Cl (s)→NH3 (g) + HCl (g) at 25°C, ΔH = 176 kJ/moland ΔS = 0.285 kJ/(mol - K).
What is the ΔG, and will this reaction be spontaneous in the forward direction?
169 kJ/mol; no
-91 kJ/mol; yes
91 kJ/mol; no
91 kJ/mol; yes
Answer:
C: 91 kJ/mol; no
Explanation:
Just took the quiz! :)
The ΔG is 91kJ/mol and the reaction is not spontaneous in the forward direction and the correct option is option 3.
What is Gibbs free energy change?Gibbs free energy, also known as the Gibbs function, Gibbs energy, or free enthalpy, is a quantity that is used to measure the maximum amount of work done in a thermodynamic system when the temperature and pressure are kept constant.
The Gibbs free energy of the system is a state function because it is defined in terms of thermodynamic properties that are state functions.
The change in the Gibbs free energy of the system that occurs during a reaction is therefore equal to the change in the enthalpy of the system minus the change in the product of the temperature times the entropy of the system.
ΔG = ΔH - TΔS
Given,
ΔH = 176kJ/mol
ΔS = 0.285kJ/mol K
T = 25⁰C = 273 + 25 = 298K
ΔG = ΔH - TΔS
ΔG = 176000 - 298 × 285
= 91070 = 91 kJ/mol
Since ΔG is positive, the reaction is not spontaneous in the forward direction.
Therefore, the ΔG is 91kJ/mol and the reaction is not spontaneous in the forward direction and the correct option is option 3.
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An electron is in a region outside the nucleus. An electron
a) Is larger than a proton and has no charge
b) Has less mass than a proton and has a negative charge
c) Is smaller than a proton and has no charge
d) Has a positive charge
Answer:
b
Explanation:
electrons lie in the orbits of the atom. they are negatively charged and they are very small in size. they have very less mass than proton. ele tron has 1/1840 mass of proton.
A student decreases the temperature of a 417 cm³ balloon from 278 K to 231 K. Assuming constant pressure, what should the new volume of the balloon be?
376 cm³
417 cm³
462 cm³
924 cm³
Answer:
346.5 cm³ or 347cm³
Explanation:
v1/T1 = v2/T2
417/278 = v2/231
v2 = 346.5 cm³
When we move from the bottom to the top of the periodic table:
Electronegativity increases and ionisation energy decreases
Both electronegativity and ionisation energy decreases
Both electronegativity and ionisation energy increases
They remain the same
Answer:
When we move from the bottom to the top of the periodic table:
Both electronegativity and ionisation energy increases.
Explanation:
The ionization energy I is the energy needed to start an electron to a gaseous atom, isolated and in a fundamental state. The electrons are attracted to the nucleus, so it is necessary to provide energy to start them. You should keep in mind that the electrons of the last layer are always lost, because they are the weakest attracted to the nucleus.
In a group, the ionization energy increases upwards because when passing from one element to the bottom, it contains one more layer of electrons. Therefore, the valence layer electrons, being further away from the nucleus, will be less attracted to it and it will cost less energy to pluck them.
On the other hand, electonegativity is defined as the ability of an element to attract electrons that link it to another element.
When descending within the same group, the atomic radius increases and the ionization energy decreases, indicating that the electrons are less attracted to the nucleus and therefore the electronegativity decreases from top to bottom.
fill in the blank
_______ is a gaseous state of matter that contains appreciable numbers of electrically charged particles.
Diamond is harder than graphite. This is a _______ observation.
Chemistry is defined as the study of _______.
Answer:
1. plasma; 2. qualitative; 3. matter;
Explanation:
PLASMA is a gaseous state of matter that contains appreciable numbers of electrically charged particles.
Diamond is harder than graphite. This is a QUALITATIVE observation.
Chemistry is defined as the study of MATTER.
Plasma is a gaseous state of matter that contains appreciable numbers of electrically charged particles.Diamond is harder than graphite. This is a qualitative observation.Chemistry is defined as the study of matter.
What is matter?Matter in chemistry, is defined as any kind of substance that has mass and occupies space that means it has volume .Matter is composed up of atoms which may or not be of same type.
Atoms are further made up of sub atomic particles which are the protons ,neutrons and the electrons .The matter can exist in various states such as solids, liquids and gases depending on the conditions of temperature and pressure.
The states of matter are inter convertible into each other by changing the parameters of temperature and pressure.Matter is always conserved according to law of conservation of matter.
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20. Which of the following is NOT true for the atoms 13N, 14N, and 'N?
a. They all have the same mass number.
b. They are isotopes.
c. They all have the same atomic number.
d. They all have 7 protons.
e. They all have 7 electrons.
Answer:
a ,e
Explanation:
math
They all have the same mass number