1. Which statement describes a compound?
A. It contains a solute.
B. Its composition can vary.
C. Its combination of atoms never changes.
D. Its components keep separate properties.
2. Which item is NOT a type of matter?
A. force
B. mixture
C. element
D. compound
3. Which combination can be used to classify all the matter on Earth?
A. forces and energy
B. atoms and elements
C. solvents and solutes
D. substances and mixtures
Why must you avoid touching the gas Spectrum tubes?
A hydrocarbon molecule contains carbon and hydrogen atoms in equal numbers. Its molar mass is 130.18 g/mol. What is the molecular formula for the hydrocarbon
Answer:
The molecular formula of the hydrocarbon is C10H10
Explanation:
Here, we are interested in finding the molecular formula for the hydrocarbon.
Since there are equal number of moles of carbon and hydrogen, then we have the molecular formula looking like;
CnHn
Kindly recall that the atomic mass of carbon is 12 a.m.u while that of hydrogen is 1 amu
so calculating the atomic mass of the compound, we have;
12(n) + 1(n) = 130.18
13n = 130.18
n = 130.18/13
n = 10.01
So the molecular formula will be C10H10
Answer:
C10H10
Explanation:
A hydrocarbon is a binary compound of carbon and hydrogen. Hence a hydrocarbon is a compound of the general formula (CH)n
Thus;
(12 + 1) n = 130.18
n= 130.18/13
n = 10
Hence the molecular formula of the compound is C10H10
What are graphs? Give an example of a graph that would be useful to you in your everyday life
Answer:
A graph can be very handy in collecting data and storing it in one place. A graph can be a very effective tool in presenting visual information rather swiftly. Hope this helps! I am learning about graphs in my course!
Explanation:
Answer:
graph) a diagram showing the relation between variable quantities, typically of two variables, each measured along one of a pair of axes at right angles.
Explanation:
Graphing is used daily. From stockbrokers to performance evaluation in companies. All use them to boost sales and meet deadlines. Even simple calculations can be assessed better by using a graph.
(let me know if this helps?)
1. What is the problem in this activity?
2. Formulate your hypothesis. (List down at least 3 hypotheses)
3. What is the dependent variable?
4. What is the independent variable?
5. Analyze your results. Which type of liquid will prevent the apple from
turning brown?
a. lemon
b. milk
Hello. You forgot to say that this question is about the possibility of using some type of product that prevents cut apples from becoming darker.
Answer and Explanation:
1. The problem with this activity is "What can you put on an apple slice to keep it from turning brown?" The problem in a scientific experiment is the element that provides a question about what is being observed.
2. Hypotheses are assumptions made about what was observed, in addition, hypotheses can answer the question shown in the problem. In the case of apples, the hypotheses can be: "Lemon juice is the most efficient product in delaying the blackening of cut apples." "Water is inefficient in preventing blackened cut apples." "Milk accelerates the blackness of cut apples."
3. The dependent viable is one that needs to be influenced by another element to bring about a result. In the case of the experiment with apples, the dependent variable is the blackening rate of the apple slices.
4. The independent variable, on the other hand, refers to the element that does not need any influence to cause a result, on the contrary, this variable acts on the dependent variable, influencing it. In the case of this experiment, the independent variable is the types of liquid tested to delay the blackening of cut apples.
5. Lemon was the most efficient liquid. Probably this efficiency is related to the lemon's ability to decrease the strength of antioxidants, due to its very low pH.
what are the strengths in the bonds of potassium bromide
Answer: Potassium Bromide (KBr) The Ionic bond formed between Potassium and Bromine is created through the transfer of electrons from Potassium (metal) to Bromine (nonmetal).
Explanation: this type of structure departs strongly from that expected for ionic bonding and ... whose roots go back to Max Planck's explanation in 1900 of the properties of ... types of interactions between elementary particles (the strong force, the weak force, ...
atmospheric pressure at elevations of 8000 feet averages about 0.72 atmospheres. Would a cabin pressurized at 500 mm hg meet federal standards
Answer:
Yes, but it must be kept at that value and do not let it to decrease more.
Explanation:
Hello.
In this case, in order to substantiate whether the cabin meet the federal standards, we need to convert the 500 mmHg to atm and compare the result with 0.72 atm by knowing that 1 atm equals 760 mmHg:
[tex]500mmHg*\frac{1atm}{760mmHg} \\\\=0.66atm[/tex]
Thus, since 0.66 atm is 0.06 atm away from the federal standard we can infer that it may meet the federal standard, however, it would not be recommended to let the pressure decrease more than that.
Yes, the cabin pressurized at 500 mm hg meets federal standards.
1 atm is approximately equal to 760 mm Hg. Therefore, the pressure is:
500 mm Hg / 760 mm Hg/atm ≈ 0.65789 atm
So, the cabin pressure of 500 mm Hg is approximately 0.65789 atmospheres. If the atmospheric pressure at an elevation of 8000 feet averages about 0.72 atmospheres, then the cabin pressure of 0.65789 atmospheres would be lower than the ambient atmospheric pressure.
To meet federal standards, cabin pressure should be maintained at an equivalent pressure that allows occupants to breathe comfortably.
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can someone pweaseee help me on this ??
Answer:
Be
Explanation:
The atomic radius decreases as you go from left to right in a period. Be has the largest radius out of those given elements.
Please help me ! Thank you
Answer:
10
Explanation:
Which of these is the term for the rate of flow of energy in a circuit?
velocity
electricity
resistance
current
Helpppp!!!!! Please help me
Answer:
10.)Weight and mass are different because only weight describes the force of gravity on an object.
11.)On a planet with more mass than earth your weight would be higher because greater gravitational pull.
On a planet with less mass than earth your weight would be less because of the lower gravitational pull.
Explanation:
Pls help, and fast plsssssssss
Answer:
The cell on the left is animal, The cell on the right is a plant cell.
Explanation:
1: cell membrane
2: chloroplast
3: cell wall
4: vacuole
5: mitochondria
6:nucleus
7: lysosome
8: cytoplasm
Things to remember, only plant cells have cell walls. Plant cells are the only ones that have chloroplast.
4.5 tons → lbs
4.5 tons equals how many pounds
Answer:
9000 pounds
Explanation:
9000 pounds
Answer: 9000 lbs.
Explanation: 4.5 tons = 9000 pounds.
Calculate the pH of a solution containing a caffeine concentration of 455 mg/L . Express your answer to one decimal place.
Answer:
Explanation:
Caffeine is a weak base with pKb = 10.4
Kb = 10⁻¹⁰°⁴ = 3.98 x 10⁻¹¹
molecular weight of caffeine = 194.2
455 x 10⁻³ g / L = 455 x 10⁻³ / 194.2 moles / L
concentration of given solution a = 2.343 x 10⁻³ M
Let the caffeine be represented by B .
B + H₂O = BH + OH⁻
a - x x x
x² / ( a - x ) = Kb
x² / ( a - x ) = 3.98 x 10⁻¹¹
x is far less than a so a -x is almost equal to a
x² = 3.98 x 10⁻¹¹ x 2.343 x 10⁻³ = 9.32 x 10⁻¹⁴
x = 3.05 x 10⁻⁷
[ OH⁻ ] = 3.05 x 10⁻⁷
pOH = - log ( 3.05 x 10⁻⁷ )
= 7 - log 3.05
= 7 - 0.484 = 6.5
pH = 14 - 6.5 = 7.5
The pH of 455 mg/L of caffeine is 7.5
Using the formula;
Mass concentration = molar concentration × molar mass
Molar mass of caffeine = 194 g/mol
Mass concentration of caffeine = 455 mg/L
Molar concentration = Mass concentration/molar mass
Molar concentration = 455 × 10^-3g/L/194 g/mol
= 0.00235 M
Let Caffeine by depicted by the general formula BH
We can now set up the ICE table as follows;
:B + H2O ⇄ BH + OH^-
I 0.00235 0 0
C - x +x +x
E 0.00235 - x x x
Note that water is present in large excess
Again; pKb of caffeine =10.4
Kb = Antilog[-pKb]
Kb = Antilog [-10.4]
Kb = 3.98 × 10^-11
Kb = [BH] [OH^-]/[:B]
3.98 × 10^-11 = [x] [x]/[ 0.00235 - x ]
3.98 × 10^-11 [ 0.00235 - x ] = [x] [x]
9.4 × 10^-14 - 3.98 × 10^-11x = x^2
x^2 + 3.98 × 10^-11x - 9.4 × 10^-14 = 0
x = 3.1 × 10^-7 M
Recall [BH] = [OH^-] = 3.1 × 10^-7 M
Now;
pOH = - log [OH^-]
pOH = log [3.1 × 10^-7 M]
pOH = 6.5
But;
pH + pOH = 14
pH = 14 - pOH
pH = 14 - 6.5
pH = 7.5
The pH of 455 mg/L of caffeine is 7.5
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Missing parts
Caffeine (C8H10N4O2) is a weak base with a pKb of 10.4. Calculate the pH of a solution containing a caffeine concentration of 455 mg/L.
Which of these is the best definition of biotechnology??
A) The study of chemical processes in living things
B) the use and application of living things and science
C) the application of engineering principles to solve medical problems
D) the study of forces
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Rank the following elements in order from least to most number of moles of atoms in a 10.0 g sample: Sn, Si, Se, S
Answer:
[tex]\rm Sn[/tex], [tex]\rm Se[/tex], [tex]\rm S[/tex], [tex]\rm Si[/tex].
Explanation:
The relative atomic mass of an element is numerically equal to the mass (in grams) of one mole of its atoms. This quantity can help estimate the number of moles of atoms in each of these four [tex]10.0\; \rm g[/tex] samples.
Look up the relative atomic mass for each of these four elements (on a modern periodic table.)
[tex]\rm Si[/tex]: [tex]28.085[/tex].[tex]\rm S[/tex]: [tex]32.06[/tex].[tex]\rm Se[/tex]: [tex]78.971[/tex].[tex]\rm Sn[/tex]: [tex]118.710[/tex].The relative atomic mass of [tex]\rm Si[/tex] is (approximately) [tex]28.085[/tex]. Therefore, the each mole of silicon atoms would have a mass of approximately [tex]28.085\; \rm g[/tex]. How many moles of silicon atoms would there be in a [tex]10.0\; \rm g[/tex] sample?
Given:
[tex]m(\rm Si) = 10.0\; \rm g[/tex]. [tex]M(\mathrm{Si}) = 28.085\; \rm g \cdot mol^{-1}[/tex].Number of mole of silicon atoms in the sample: [tex]\displaystyle n(\mathrm{Si}) = \frac{m(\mathrm{Si})}{M(\mathrm{Si})} = \frac{10.0\; \rm g}{28.085\; \rm g \cdot mol^{-1}}\approx 0.356\; \rm mol[/tex].
Similarly:
[tex]\displaystyle n(\mathrm{S}) = \frac{m(\mathrm{S})}{M(\mathrm{S})} = \frac{10.0\; \rm g}{32.06\; \rm g \cdot mol^{-1}}\approx 0.312\; \rm mol[/tex].
[tex]\displaystyle n(\mathrm{Se}) = \frac{m(\mathrm{Se})}{M(\mathrm{Se})} = \frac{10.0\; \rm g}{78.971\; \rm g \cdot mol^{-1}}\approx 0.127\; \rm mol[/tex].
[tex]\displaystyle n(\mathrm{Sn}) = \frac{m(\mathrm{Sn})}{M(\mathrm{Sn})} = \frac{10.0\; \rm g}{118.710\; \rm g \cdot mol^{-1}}\approx 0.0842\; \rm mol[/tex].
Therefore, among these [tex]10.0\; \rm g[/tex] samples:
[tex]n(\mathrm{Sn}) < n(\mathrm{Se}) < n(\mathrm{S}) < n(\mathrm{Si})[/tex].
It is not a coincidence that among these four samples, the one with the fewest number of atoms corresponds to the element with the largest relative atomic mass.
Consider two elements, with molar mass [tex]M_1[/tex] and [tex]M_2[/tex] each. Assume that [tex]n_1[/tex] moles and [tex]n_2[/tex] moles of atoms of each element were selected, such that the mass of both samples is [tex]m[/tex]. That is:
[tex]m = n_1\cdot M_1[/tex].
[tex]m = n_2\cdot M_2[/tex].
Equate the right-hand side of these two equations:
[tex]n_1 \cdot M_1 = n_2\cdot M_2[/tex].
[tex]\displaystyle \frac{n_1}{n_2} = \frac{M_2}{M_1} = \frac{1/M_1}{1/M_2}[/tex].
In other words, the number of moles atoms in two equal-mass samples of two elements is inversely proportional to the molar mass of the two elements (and hence inversely proportional to the formula mass of the two elements.) That explains why in this question, the sample containing the smallest number of atoms corresponds to element with the largest relative atomic mass among those four elements.
Concentration data is commonly monitored during a reaction to determine the order with respect to a reactant. Consider the types of observations listed, and determine which order is likely for that reactant. Assume all other factors are held constant.
1. An increase in the concentration of the reactant in solution causes the reaction rate to increase exponentially.
a. first order
b. second order
c. zero order
2. The reaction rate increases in direct proportion to the concentration of the reactant in solution.
a. first order
b. second order
c. zero order
3. The reaction rate is constant regardless of the amount of reactant in solution.
a. first order
b. second order
c. zero order
Answer:
1) first order
2) second order
3) zero order
Explanation:
The curve of a first order reaction shows it to be exponential. In fact for a first order reaction, the concentration at a time t is an exponential function;
[A]t= [Ao] e^-kt
Where
[A]t = concentration at time =t
[Ao]= initial concentration
k= rate constant
t= time
For a second order reaction, the rate of reaction is directly proportional to the concentration of reactants.
For zero order reactions, rate of reaction is independent of concentration hence rate = k(rate constant)
The concentration data has been required for the determination of the rate of reaction. Based on the concentration of reactant and product, the rate has been determined.
1. For the first-order reaction, there has been an exponential increase in the rate of the reaction with the increase in the reactant concentration. The rate has been dependent on the concentration of the reactant.
Thus the correct option is A.
2. Irrespective of the first-order kinetic, in the second-order reaction, the rate of reaction has been directly proportional to the concentration of the reactant in the solution.
Thus option B is correct.
3. The zero-order reaction has been independent of the concentration of the reactant. The rate of reaction has been constant with an increase in the reactant concentration.
Thus option C is correct.
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calculate the mass of N2 gas which has a volume 0.227 at STP
Please tell me the answers to A, B, and C
Answer:
A=element
B=compond
C=solution
match the number of negative charges to the number of positive charges to make each combination balanced (see image for answer) just say like thanks, or a fun fact or something for ten points in the answers lol
Answer : The correct match is:
1 positive charge = 1 negative charge
2 positive charges = 2 negative charges
3 positive charges = 3 negative charges
Explanation :
As we now that there are three subatomic particles which are protons, electrons and neutrons.
The protons and neutrons are located inside the nucleus and electrons are located around the nucleus.
The protons are positively charged, the electrons are negatively charged and neutrons are neutral.
As we know that all the things are made up of charges and opposite charges attract to each other.
In a neutral atom, the positive charges and negative charges are balanced in an object. That means, in neutral atom the number of positive charges are equal to the negative charges.
So we can say that:
1 positive charge = 1 negative charge
2 positive charges = 2 negative charges
3 positive charges = 3 negative charges
Answer:
1 positive---- 1 negative
2 positive---- 2 negative
3 positive---- 3 negative
Explanation:
edge 2023
What is the Kc equilibrium-constant expression for the following equilibrium? S8(s) + 24F2(g) 8SF6(g)
Answer:
[tex]Kc=\frac{[SF_6]^8}{[F_2]^2^4}[/tex]
Explanation:
Hello.
In this case, for the undergoing chemical reaction:
[tex]S_8(s) + 24F_2(g) \rightleftharpoons 8SF_6(g)[/tex]
We consider the law of mass action in order to write the equilibrium expression yet we do not include S8 as it is solid and make sure we power each gaseous species to its corresponding stoichiometric coeffient (24 for F2 and 8 for SF6), thus we obtain:
[tex]Kc=\frac{[SF_6]^8}{[F_2]^2^4}[/tex]
Best regards!
An ion formed from an atom has a 1- charge. The number of electrons present in the ion is 36 and the number of neutrons is 46. Identify the element by typing the name. For example: Hydrogen or Sodium.
Answer:
Bromine can become an ion when it gains an electron. Br- is a negative ion. Its known as an anion. Bromine has 35 protons=35 electrons. one added electron gives it 36 electrons and it becomes an anion.
Explanation:
Bromine can have isotopes having 44 and 46 neutrons.
Pb12 (s) = Pb+2 (aq)
+
2 ]- (aq)
Answer:
this
Explanation:
What is the unit rate of the better deal? (Number answers only.)
LaTeX: \frac{160\:miles}{5\:gallons}\:or\:\frac{315\:miles}{9\:gallons}160 m i l e s 5 g a l l o n s o r 315 m i l e s 9 g a l l o n s
The better deal has a unit rate of [m] miles per gallon.
what is functional group of ethers?
Answer:
Explanation:The ether functional group consists of an oxygen atom that forms single bonds with two carbon atoms
Is air a homogeneous heterogeneous mixture or substance
Answer:
look at the explanation
Explanation:
The air that you breathe is a homogeneous mixture of oxygen, nitrogen, argon, and carbon dioxide, along with other elements in smaller amounts. Because each layer of the Earth's atmosphere has a different density, each layer of air is its own homogeneous mixture.
Hope this helps. :)
Facilitated diffusion is a form of passive transport and involves the movement of molecules (like glucose) that are too large to just go through the cell membrane without help. These larger molecules move through the cell membrane from High concentration to Low concentration with the help of _____________________________.
Answer: Membrane Protiens
Explanation:
In facilitated diffusion, molecules diffuse across the plasma membrane with assistance from membrane proteins, such as channels and carriers. A concentration gradient exists for these molecules, so they have the potential to diffuse into (or out of) the cell by moving down it.
Balance the equations by inserting coefficients as needed.
equation 1:
PCl_{3} + Cl_{2} -> PCl_{5}
PCl3+Cl2⟶PCl5
equation 2:
Mg_{3}N_{2} + HCl -> MgCl_{2} + NH_{3}
Mg3N2+HCl⟶MgCl2+NH3
Answer:
first one is already balanced
2. MgN2+6HCl->3MgCl2+2NH3
Explanation:
To balance the equations, we need to ensure that the same number of each type of atom is present on both sides of the equation. Here's how we can balance the given equations:
Equation 1: PCl₃ + Cl₂ -> PCl₅
In this equation, there are 1 phosphorus (P) atom, 3 chlorine (Cl) atoms, and 5 chlorine (Cl) atoms. To balance the equation, we can put a coefficient of 2 in front of PCl₃ to have 2 phosphorus atoms, and a coefficient of 5 in front of Cl₂ to have 10 chlorine atoms:
2PCl₃ + 5Cl₂ -> PCl₅
Now the equation is balanced with 2 phosphorus atoms and 10 chlorine atoms on both sides.
Equation 2: Mg₃N₂ + HCl -> MgCl₂ + NH₃
In this equation, there are 3 magnesium (Mg) atoms, 2 nitrogen (N) atoms, 2 hydrogen (H) atoms, and 1 chlorine (Cl) atom.
To balance the equation, we can put a coefficient of 3 in front of HCl to have 3 hydrogen atoms, and a coefficient of 2 in front of NH3 to have 2 nitrogen atoms:
Mg₃N₂ + 3HCl -> MgCl₂ + 2NH₃
Now the equation is balanced with 3 magnesium atoms, 2 nitrogen atoms, 6 hydrogen atoms, and 2 chlorine atoms on both sides.
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All living things are made of one or more cells. Which is true of all cells?
If your hypothesis is incorrect you should...
I need help on this. It’s kinda confusing...
Answer: here u go
Explanation:
A. 3.7 x 10^4
B. 4.56 × 10^-8
C. 8.01 × 10^6
Work for A:
Step 1
To find a, take the number and move a decimal place to the right one position.
Original Number: 37,000
New Number: 3.7000
Step 2
Now, to find b, count how many places to the right of the decimal.
New Number: 3 . 7 0 0 0
Decimal Count: 1 2 3 4
There are 4 places to the right of the decimal place.
Step 3
Building upon what we know above, we can now reconstruct the number into scientific notation.
Remember, the notation is: a x 10b
a = 3.7 (Please notice any zeroes on the end have been removed)
b = 4
Now the whole thing:
3.7 x 104
Step 4
Check your work:
104 = 10,000 x 3.7 = 37,000
Work for B:
Step 1
To find a, take the number and move a decimal place to the right one position.
Original Number: 456
New Number: 0.0000000456
Step 2
Now, to find b, count how many places to the right of the decimal.
New Number: 0 . 0 0 0 0 0 0 0 4 5 6
Decimal Count: 1 2 3 4 5 6 7 8 9 10
There are 2 places to the right of the decimal place.
Step 3
Building upon what we know above, we can now reconstruct the number into scientific notation.
Remember, the notation is: a x 10b
a = 4.56
b = 2
Now the whole thing:
4.56 x 102
Step 4
Check your work:
102 = 100 x 4.56 = 456
Work for C:
Step 1
To find a, take the number and move a decimal place to the right one position.
Original Number: 8,010,000
New Number: 8.010000
Step 2
Now, to find b, count how many places to the right of the decimal.
New Number: 8 . 0 1 0 0 0 0
Decimal Count: 1 2 3 4 5 6
There are 6 places to the right of the decimal place.
Step 3
Building upon what we know above, we can now reconstruct the number into scientific notation.
Remember, the notation is: a x 10b
a = 8.01 (Please notice any zeroes on the end have been removed)
b = 6
Now the whole thing:
8.01 x 106
Step 4
Check your work:
106 = 1,000,000 x 8.01 = 8,010,000
Hope this helps!