A student conducting a calorimetry investigation determines a negative ∆H. What does the negative value indicate about the reaction?
A. The reaction synthesized a single product.
B. The reaction was exothermic.
C. The reaction absorbed energy.
D. The reaction involved decomposition.
Answer:
a
Explanation:
correct
Which diagram represents a physical change,only?
Is the moons rate rotation that same as earths
Answer:
no
Explanation:
Answer:no
Explanation:The moon orbits the Earth once every 27.322 days. It also takes approximately 27 days for the moon to rotate once on its axis.
Briefly explain why the bulk temperature of the water remains low (at room temperature)
What is the density of aluminium? |
एल्यूमीतनयम का घनत्व कतना होता है?
A : 2.7 g/cm3 | 2.7 g/cm3
B : 3.7 g/cm3 | 3.7 g/cm3
C : 4.7 g/cm3 | 4.7 g/cm3
D : 5.7 g/cm3 | 5.7 g/cm3
Ans: A : 2.7 g/cm3 | 2.7 g/cm3
Answer:
answer 2.7
Explanation:
a.2.7g/cm3
What is the same on the left and right side of a balanced equation? Explain your answer.
Answer:
Number of atoms of elements are same on left and right side of balance equation.
Explanation:
Every chemical reaction must follow the law of conservation of mass. According to which mass can neither be created nor destroy but it change from one to another form. It means mass remain conserved. That is why we need to balance the chemical equation because mass remain same on both side of equation. Consider the example,
Chemical equation:
N₂ + H₂ → NH₃
We can see that nitrogen and hydrogen react with each other and from ammonia. We need to balance the equation to have equal amount on both side.
Balance chemical equation:
N₂ + 3H₂ → 2NH₃
It means mass remain same but change from one to another form.
A balanced equation is one that is having a chemical reaction where the numbers of atoms. Here the number of elements in each reaction and the total charges are the same. This includes both the reactant and the product.
However, the mass and charge are balanced on both sides of the reaction. Hence the left and the right side is always equal to the number of atoms. Thus the chemical reaction is a balance of atoms involved in the reaction.Learn more about the same on the left and right sides of a balanced equation.
brainly.ph/question/20750343.
As we will soon see in Section 4.5, gasoline is a complex mixture of alkanes and other hydrocarbons, and the term "octane rating" is used as a standard measure of the performance of engine fuel. In the petroleum industry, one area of interest is the use of catalysts to convert unbranched alkanes and branched alkanes with higher octane ratings (Journal of the Japan Petroleum Institute 2004, 47, 1–10). For example, heptane can undergo isomerization in the presence of suitable catalysts to give eight different constitutional isomers, all of which are branched alkanes with the molecular formula C7H16. Draw all eight constitutional isomers, making sure not to draw the same compound twice.
Answer:
Explanation:
C₇H₁₆ is heptane and it has nine isomers (n-heptane and the remaining 8 constitutional isomers). Constitutional isomers are compounds with the same molecular formula but different structural formula or atom connectivity.
The constitutional isomers of n-pentane are 2-methylhexane, 3-methylhexane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane, 3-ethylpentane and 2,2,3-trimethylbutane. There structures are in the picture attached
HEEELLLPPPP:(!!!!! im stuckkkk!!!
Answer:
LIGHT
AIR
SHELTER
FOOD
WATER
Answer:
light
air
shelter
food
water
What is the total pressure of a container in kpa if the partial pressures are 1.25 atm and 66.7 psi?
Answer:
586 kpa(kilopascal/1000 pascals)
Explanation:
given 1.24 atm(standard atmosphere), and 66.7 psi(pound force per square inch).
To find the total pressure we should use dalton's law of partial pressures which is the sum of the pressures of each individual gas.
then we convert them to pascals and divide by 1000 to get the measurement in kilopascal.
knowing that 1 atmosphere is proportional to around 14.696 psi. We can multiply our given measure of atm by that and sum it by psi like so. 1.24×14.6959 = 18.22298.
Then,
18.22298+ 66.7 = 84.92298
psi.
Since 1 psi is proportional to around 6894.76 pascals. 1 psi will be 68.9476 kilopascal. 84.92298 * 6.89476 = 585.523336 ≈ 586
A scientist plants two rows of corn for experimentation. She puts fertilizer on row 1 but does not put fertilizer on row 2. Both rows receive the same amount of sun and water. She checks the growth of the corn over the course of five months.
Q9) What is the independent variable in this experiment? Why is this variable independent?
Q10) What is the dependent variable in this experiment? Why is this a dependent variable?
Q11) What variables are controlled in this experiment? Why are/is these/this variable control variable(s)?
Answer:
Q9. The independent variable in this experiment is the fertilizer. It is independent because she manipulating the variable to compare the growth.
Q10. The dependent variable in this experiment is the amount of growth of the corn. It is this because the growth depends on what the scientist did on the corn.
Q11. The variable controlled in this experiment is the amount of sun and water. These two variables never change so this is why it is the control.
Explanation:
Answer:
Explanation:
independent - 5 months dependent - sun controlled - water and the fertilizer
One differentiating characteristic between vascular and nonvascular plants is the lack of active transport structures in the nonvascular plants. How does the lack of xylem or phloem contribute to the smaller size of the nonvascular plants?
Nonvascular plants are smaller because xylem and phloem help a plant stand up taller.
Nonvascular plants have other transport structures that are microscopic and therefore take up less room.
Nonvascular plants rely upon concentration gradients to move food and water, which only works over small distances.
Nonvascular plants are smaller because they don’t photosynthesize as much as vascular plants and don’t get enough food.
Answer:
One of the most important characteristics of non-vascular plants is the absence of vascular tissues. Non-vascular plants do not have the vascular tissues known as xylem and phloem. ... As they do not have any vascular tissue, they cannot retain water for long time or transport it to other parts of the plant.
Explanation:
Answer:
fern
Explanation:
A new element was discovered. It’s average atomic mass was found to be 245.6 amu. Isotope #1 has a mass of 243.2 amu; isotope #2 has a mass of 244.9 amu; isotope #3 has a mass of 247.2 amu. Which isotope is most likely to be the most abundant?
A
Isotope 1
B
Isotope 2
C
Isotope 3
D
They all contribute the same amount
Answer:
B. Isotope 2
Explanation:
Isotopes can be defined as the atom of an element that has the same number of protons but different number of neutrons. This ultimately implies that, the isotopes of an element have the same atomic number (number of protons) but different atomic mass (number of nucleons).
Basically, the atomic mass of any chemical element found in the periodic table is equal to the weighted average of all its isotopes. Therefore, the isotope with the closest mass to the weighted average would be the most abundant.
In this scenario, a new element was discovered with an average atomic mass of 245.6 amu.
Isotope #1 has a mass of 243.2 amu.Isotope #2 has a mass of 244.9 amu.Isotope #3 has a mass of 247.2 amu.Hence, the isotope which is most likely to be the most abundant is isotope #2 that has a mass of 244.9 amu because it is closest in mass to the relative atomic mass (weighted average) of 245.6 amu.
The water cycle would not be possible without ______ and ________.
a. evaporation; condensation
b. gravity; sun
c. precipitation; rain
d. gravity; precipitation
Describe what will eventually happen to the water level in the beaker.
Explain your reasoning.
Answer:
The water level in the beaker will eventually go down because some of the liquid water changes into ice (a solid) and the particles get closer together in the beaker. The water level in the beaker will eventually stay the same because some of the liquid water changes into water vapor (a gas) and leaves the beaker.
Lithium metal will react with aqueous aluminum sulfate. Write and balance the equation for this rxn, and then determine how many g of aluminum will result from 68.6 g lithium reacting with aluminum sulfate in excess.
Answer:
88.2 gram of aluminium .
Explanation:
6Li + Al₂ ( SO₄)₃ = 3Li₂SO₄ + 2Al
6 x 7 g 2 x 27 g
42 gram of lithium produces 54 gram of aluminium
68.6 gram of lithium will produce 88.2 gram of aluminium .
88.2 gram of aluminium will be produced.
What is the oxidation number of Oxygen?
-1
........... ..............
50 POINTS
Assume that the variables x and y are inversely related. If k = 18, what is the value of y for each of the following points?
Be sure and record your data to be used in the following problem.
х y k
1 18
A: 18,0.05,9
2 18
A: 0.11,36,9
3 18
A: 0.16,6,54
6 18
A: 0.33,108,3
9 18
A: 162,0.5,2
18 18
A: 324,0.75,1
Answer:
9/.05=180. I think it's 1
Explanation:
If x and y are inversely proportional then the product of xy =k or y=k/x
I WILL MARK YOU THE BRANLIEST!!!
Which property shows that electrons are quantized?
A. Electrons are attached to protons.
B. Each electron has its own "address."
C. Each electron carries a charge.
D. Electrons have very little mass.
Answer:
B. Each electron has its own "address."
Explanation:
This is the correct answer.
Good luck with the rest, and have a good day : )
Each electron has its own "address." Therefore, the correct option is option B among all the given options.
What is quantization?The elementary electric charge of the electron is a negative one, making it a subatomic particle. Due to their lack of components or substructure, electrons, which are part of the lepton particles family's first generation, are typically regarded to be elementary particles. The mass of an electron is roughly 1/1836 that of a proton.
The electron has a half-integer intrinsic rotational momentum that is represented in terms of the decreased Planck constant,, among its quantum mechanical features. The rule of exclusion developed by Pauli states that because electrons are fermions, no two of them may be in the same quantum state. Since they're capable of collide against other particles as well as can be bent like light, electrons, like all primary particles, display both wave and particle characteristics. Each electron has its own "address."
Therefore, the correct option is option B.
To know more about quantization, here:
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Planets that will sink in water ?
Answer:
Any planet that is made up of mostly rock.
. Which of these is an example of a scientific observation? *
AThe rock is smooth and gray."
BWhat is the best brand of soap?"
CMost people drive black cars."
DThe sun's light helps plants grow."
Answer:
D. The sun's light helps plants grow
Explanation:
This is a scientific observation, because it is describing the structure of a living thing.
Doing Calculations The metal thallium occurs naturally as 30 percent thallium-203 and 70
percent thallium-205. Calculate the atomic mass of thallium. Enter your numerical answer in
the blank provided please help
Answer:
Average atomic mass of thallium = 204.4 amu.
Explanation:
Given data:
Abundance of thallium-203 = 30%
Abundance of thallium-205 = 70%
Average atomic mass = ?
Solution:
Average atomic mass of thallium = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass of thallium = (30%×203)+(70%×205) /100
Average atomic mass of thallium = 6090 + 14350 / 100
Average atomic mass of thallium = 20440 / 100
Average atomic mass of thallium = 204.4 amu.
1)Fluorine-21 has a half life of approximately 5 seconds. If you start with 100g, how much
would remain after 10 seconds?
What’s the answr
Answer:
25 g
Explanation:
The following data were obtained from the question:
Half life (t½) = 5 s
Original amount (N₀) = 100 g
Time (t) = 10 s
Amount remaining (N) =..?
Next, we shall determine the decay constant for the disintegration. This can be obtained as follow:
Half life (t½) = 5 s
Decay constant (K) =.?
K = 0.693 / t½
K = 0.693 / 5
K = 0.1386 s¯¹
Finally, we shall determine the amount of the isotope that remained after 10 s as follow:
Original amount (N₀) = 100 g
Time (t) = 10 s
Decay (K) = 0.1386 s¯¹
Amount remaining (N) =..?
Log (N₀/N) = kt /2.303
Log (100/N) = (0.1386 × 10) / 2.303
Log (100/N) = 1.386 / 2.303
Log (100/N) = 0.6018
Take the anti log of 0.6018
100/N = antilog (0.6018)
100/N = 4
Cross multiply
100 = N × 4
Divide both side by 4
N = 100/4
N = 25 g
Therefore, the amount remaining after 10 s is 25 g
Which statement describes all chemical changes, but not all physical changes?
Answer:
A new substance forms.
Explanation:
Answer:
B
Explanation:
Releases sugar (glucose) into the blood stream to power cells A. Brain B. Heart C. Liver D. Stomach and intestines
Answer:
C Liver
Explanation:
The chemical formula for calcium chloride is
Answer: anhydrous CaCl 2 :0H 2 O
monohydrate CaCl 2 :1H 2 O
a di-hydrate CaCl 2 :2H 2 O
Explanation:
Electronic configuration PLZZZ GUYSS(sub shell distribution) for L shell will be .........................
Answer:
Shells
The maximum number of electrons that can be accommodated in a shell is based on the principal quantum number (n). It is represented by the formula 2n2, where ‘n’ is the shell number. The shells, values of n, and the total number of electrons that can be accommodated are tabulated below.
Shell and ‘n’ value Max. Electrons in the Electron Configuration
K shell, n=1 2*12 = 2
L shell, n=2 2*22 = 8
M shell, n=3 2*32 = 18
N shell, n=4 2*42 = 32
L shell: n =2
hence,
2n²
= 2(2)²
i.e. 8 electrons can fit in the l shell
hence max no. of electrons is 8
so configuration in L shell is,
2, 8...
How would you expect a positive particle approaching another positive particle to behave?
Answer:
They would produce a repulsive force to another
Explanation:
A positive particle approaching another positive particle will repulse it.
According to coulomb's law "like charges repel one another and unlike charges attract".
A charge is an intrinsic property of any matter.
When like charges e.g positive and positive or negative and negative charges are in the vicinity of one another, they repel each other.
When unlike charges; positive and negative are brought together, they simply attract one another.
Therefore, we expect that a positive particle approaching another positive particle will repel one another.
When a positive particle approaches another positive particle, the two particles repel or move away from each other.
In electrostatics we know that like charges repel while unlike charges attract. Therefore when we have two like charges, they simply move away from each other. This is known as repulsion of charges.
Hence, two positive charges approaching each other will simply move away and repel each other according to the laws of electrostatics.
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Is br a magnetic or non magnetic
Answer: Non-magnetic
Explanation:
Answer:
br is a non magnetic. hope this helps.
Im confused please help :(
1.) When kinetic energy is high, velocity is high.
true or false
2.) When potential energy is high, velocity is at its highest.
true or false
Answer: #1: true
#2: false
Explanation: I’m not 100% sure though!
Which statement describes an intensive property of matter?
Answer:
hope it helped you.
Explanation:
The properties of matter that do not depend on the size or quantity of matter in any way are referred to as an intensive property of matter. Temperatures, density, color, melting and boiling point, etc., all are intensive property as they will not change with a change in size or quantity of matter.