PLZ HELP ME A girl throws a ball and her dog chases it. What characteristic of living things is this dog demonstrating as it chases the ball?
A. Cells
B. Reproduction
C. Growth
D. Response
Which statement best describes the destiny of an atoms nucleus?
Answer:
The answer would be: An atom’s nucleus occupies very little of the atom’s volume but contains most of its mass
Explanation:
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom.
Almost all of the mass of an atom is located in the nucleus, with a very small contribution from the electron cloud.
Refer to https://en.wikipedia.org/wiki/Atomic_nucleus for further understanding
describe how thin layer chromatography is used in the isolation and extraction of lipids
Thin layer chromatography(TLC) works with the principle of separation through adsorption.
It is used in the isolation and extraction of lipids through the following steps:
apply the lipid samples spots in the bottom of the plate.also apply sample solution to the marked spotpour the mobile phase into the TLC chamber and use a moist filter paper to cover it. this is done to maintain equal humidity.then place the plate in the TLC chamber and close it with a lid.the plate is immersed into the solvent (mobile phase) for its development. this is done, keeping in mind that the sample spot should be above the solvent.once the sample spots are developed, they are removed and dried.this is later viewed using the UV light chamber to see the isolation of the lipid sample.Learn more here:
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Identify what type of reaction is taking place:
CH3CH3 + Br2 -> CH3Br + HBr
A. Addition
B. Fermentation
C. Substitution
D. Elimination
Which of the following is the best definition of ethics?
A. The maintenance of a stable internal environment
B. Response to external stimuli
C. A set of guidelines for fair conduct during an experiment
D. A multistep process whose last step controls what happens in an
earlier step
Answer:
C
Explanation:
I believe the answer is C.
Does the following word describe a theory, law, or both
“Simple”
A) LAW
B) THEORY
C) BOTH THEORY AND LAW
Answer:
B
Explanation:
I would say theory since a law is already set and proven by evidence. Theories arent necessarily proven.
Hòa tan hoàn toàn 10 gam hỗn hợp hai oxit CuO và Fe2O3 cần 100ml dung dịch HCl 3,5M. Khối lượng CuO và Fe2O3 có trong hỗn hợp ban đầu lần lượt là
Answer:
CuO+2HCl>h2o+CuCl2
fe203+6hcl->2fecl3+3h2O
gọi CuO, fe2o3 lần lượt là x,y
80x+160y=10
2x+6y=0.35
giải phương trình ta dc hai số x,y(tính phương trình kia ra)
cuo ban đầu sẽ là :60*x=z
fe203 ban đầu sẽ là :10-z=
Explanation:
question 8 chemistry help
Answer:
Sorry,I can't do this because i don't know this questions answer.
The lattice energy for an ionic compound cannot be measured directly but can be calculated from the Born-_____ cycle, using a series of individual steps for which all enthalpies are known except for the lattice energy. This method is an application of Hess's law which, states that the overall energy change for a process is given by the _____ of the enthalpy changes for the individual steps.
Answer:
first is HABER
second is SUM
Explanation:
pls mark brainliest
A fixed mass of gas has a volume of 92 cm cube and 3 degrees Celsius. What will be its volume at 18 degrees celsius if the pressure remains constant?
Answer:
94.8454
Explanation:
Let volume be V
Let Temperature be T
V1= 92
T1= 3C but to kelvin 273+3= 300K
V2= ?
T2= 18 C but to kelvin 18+273= 291
[tex] \frac{v1}{t1} = \frac{v2}{t2} [/tex]
[tex] \frac{92}{300} = \frac{v2}{291} [/tex]
[tex]v2 \times 300 = 92 \times 291[/tex]
[tex]v2 = \frac{92 \times 291}{300} [/tex]
[tex]v2 = 94.8454[/tex]
A student in a lab holds an iron nail over an open flame, and no reaction occurs. The nail is then filed, creating small pieces of
iron shavings. These pieces burn brightly when placed over an open flame.
Which statement accurately identifies one of the changes that occurs as a physical or chemical change?
Formation of small pieces of iron shavings is a physical change whereas burning of pieces of iron shavings is chemical change.
Formation of small pieces of iron shavings is an example of physical change because it can be changed again into nail while on the other hand, burning of pieces of iron shavings on the flame is an example of chemical change because it can't change again into its original shape. Physical change is a change in matter which does not change the chemical properties of the matter whereas chemical change is a change in matter which change the chemical properties of the matter.
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During a lab experiment performed at STP conditions, you prepare HCl by reacting 100. ml of Cl2 gas with an excess of H2 gas.
How many ml of a solution of Ba(OH)2 0.230M do you need to neutralize all the HCl produced?
Answer: 19.4 mL Ba(OH)2
Explanation:
H2(g) + Cl2(g) --> 2HCl(aq) (make sure this equation is balanced first)
At STP, 1 mol gas = 22.4 L gas. Use this conversion factor to convert the 100. mL of Cl2 to moles.
0.100 L Cl2 • (1 mol / 22.4 L) = 0.00446 mol Cl2
Use the mole ratio of 2 mol HCl for every 1 mol Cl2 to find moles of HCl produced.
0.00446 mol Cl2 • (2 mol HCl / 1 mol Cl2) = 0.00892 mol HCl
HCl is a strong acid and Ba(OH)2 is a strong base so both will completely ionize to release H+ and OH- respectively. You need 0.00892 mol OH- to neutralize all of the HCl. Note that one mole of Ba(OH)2 contains 2 moles of OH-.
0.00892 mol OH- • (1 mol Ba(OH)2 / 2 mol OH-) • (1 L Ba(OH)2 / 0.230 M Ba(OH)2) = 0.0194 L = 19.4 mL Ba(OH)2
Technician A says that the freezing point of a substance is the temperature at which the substance changes state from a solid to a liquid. Technician B says that the freezing point of a substance is the temperature at which the substance changes state from a liquid to a solid. Who is correct
Answer: Technician B
Explanation:
Technician B is correct. The freezing point of a substance is the temperature at which the substance changes state from a liquid to a solid.
Technician A is incorrect. On the other hand, the melting point of a substance is the temperature at which the substance changes state from a solid to a liquid.
Classify Sr(OH)2 as a strong
base or a weak base.
Strong Base or Weak Base
this is a strong base and is one of the many bases that you're required to memorize.
What happens when acetylene reacts with silver powder?
In what form is radiation emitted from the earth's surface
back into the atmosphere?
Answer:
thermal radiation
Explanation:
Outgoing Long-wave Radiation (OLR) is electromagnetic radiation of wavelengths from 3–100 μm emitted from Earth and its atmosphere out to space in the form of thermal radiation. It is also referred to as up-welling long-wave radiation and terrestrial long-wave flux, among others.
what is a cubic unit cell ?
cubic unit cell is the smallest repeated unit which have all angles equal to 90 and all have edge lengths equal
It is the type of the Unit cell which is having all angles equal to 90 and all sides equal to each other
it's is a unit cell with cubic structure
A chemist determines by measurements that 0.0550 moles of nitrogen gas participate in a chemical reaction. Calculate the mass of nitrogen gas that participates.
Be sure your answer has the correct number of significant digits.
The mass of nitrogen gas that participated in the chemical reaction is 1.54g
HOW TO CALCULATE MASS OF AN ELEMENT:
Mass of a substance can be calculated by multiplying the number of moles in mol of the substance by its molecular mass in g/mol. That is;mass (M) = molar mass (MM) × number of moles (n)According to this question, a chemist determines by measurements that 0.0550 moles of nitrogen gas (N2) participate in a chemical reaction.
The molecular mass of nitrogen gas (N2) = 14.01(2)= 28.02g/mol
Hence, the mass of the nitrogen gas that participated in the chemical reaction is calculated as follows:
Mass (g) = 0.0550 mol × 28.02 g/molMass = 1.5411Therefore, the mass of nitrogen gas that participated in the chemical reaction is 1.54g
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The world is made up of
Answer:
Explanation:
The world is made up of living beings .
career in chemistry list ten
Answer:
Analytical Chemist
Forensics
Toxicologist
Biochemist
Chemical Engineer
Laboratory Technician
Pharmacologist
Chemical Technician
Materials Scientist
Environmental Chemist
Tìm hóa trị của Fe trong hợp chất : FESO4, FE2(SO4)3, FR(OH)2, FE(OH)3
Answer: Fe hóa trị II trong các hợp chất: FeSO4, Fe(OH)2
Fe hóa trị III trong các hợp chất: Fe2(SO4)3, Fe(OH)3
Explanation:
A small gap in skit in railway track why
Answer:
To reduce the bending of the railway
Explanation:
During summer(heat) metals tend to expand in size. The skits/gaps are present in the railway so that the metal could expand without causing bending of the railway track.
.) What happens when Carbon dioxide gas is Collected down ward of water ?
when carbon dioxide gas is collected down ward of water wet gas is collected by the downward displacement of water . This is used for gases that are not very soluble in water . ... In water , carbon dioxide produces a weakly acidic solution , carbonic acid .
explain the importance of measurement in our daily life
Convert 16.7 inches to yards (there are 3 feet in a yard)
Using the method of dimensional analysis
Answer:
Explanation:
16.7 inches [1 foot / 12 inches] [1 yard / 3 feet] Notice how the units cancel each other out. You do have numbers in the denominator. What you get, looks like this
16.7
------
(12 * 3)
16.7 / 36
0.4639 yrds
what charge does an atom that has lost electrons have?
Answer:
when an atom loses electrons, it will then contain more protons. Thus, the charge of the atom become positive.
lanthanides and actinides are kept separately in the periodic table. why?
full form of soil pH
Answer:
PH STANDS FOR POTENTIAL OF HYDROGEN .
It represents the ratio of Hydronium ions (H3O) to Hydroxide ions (OH). It is a measure of acidity and alkalinity of a solution.
FOLLOW MEnumber of moles from the formula is multiplied by the atomic mass of each _______, and then all those masses are added together.
A)
atom
B)
particle
C)
molecule
D)
electron
Answer:
D. electron
Explanation:
Use the periodic table to identify the element indicated by each electron configuration by typing in the chemical symbol for the element.
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