Answer:
When light is shone on to the surface of a metal, its electrons absorb small amounts of energy and become excited into one of its many empty orbitals. The electrons immediately fall back down to lower energy levels and emit light. This process is responsible for the high luster of metals.
Explanation:
Your well-wisher :-)
Which of the following chemical formulas represents a molecule?
H2 CO2 SiO2 NH3
Answer:
H2
Explanation:
H (or hydrogen), being a halogen, as an atom, has 7 valence electrons. This means that it naturally bonds with another atom of the same isotope in order to reach the desired total of valence electrons: 8.
So... H+H = H2. EZ
Answer:
its all of them
Explanation:
i just did it lol but just incase, "Molecules are made of two or more atoms that are chemically bonded together. The atoms can be of the same element or of different elements. Therefore, H2, CO2, SiO2, and NH3 are all molecules."
which statement best explains why so many fossils look different from the millions of species currently living on Earth?
A. The rock that makes up the fossils has broken down over time
B. Most species that have lived on Earth are now extinct
C. The fossil record is filled with inaccuracies
D. Organisms are becoming simpler over time through evolution
Answer:
B.
Explanation:
Most species that have lived on Earth are now extinct
<><><><><><><><><><><><><><><><><><><><><><><><>
A P E X
The statement that best explains why so many fossils look different from the millions of species currently living on Earth is: B. Most species that have lived on earth are now extinct.
What are fossils ?
The fossil record is evidence that life on Earth has changed over time, with new species evolving and old ones going extinct. It shows the wide range of life that existed throughout Earth's history, including many species that no longer exist today.
The diversity of fossils is primarily due to the extensive range of species that have lived and gone extinct throughout the history of life on Earth.
Although some fossils may have changed over time or contain inaccuracies, they are still crucial for understanding the evolutionary relationships among different species.
Hence, option B is correct.
Find more on fossils:
https://brainly.com/question/6867325
#SPJ3
Can someone help me with this chem question?
Answer:
Malleable
Explanation:
Why is chemistry important? i need 5 paragraph please
Answer:
Chemistry has a reputation for being a complicated and boring science, but for the most part, that reputation is undeserved. Fireworks and explosions are based on chemistry, so it's definitely not a boring science. If you take classes in chemistry, you'll apply math and logic, which can make studying chemistry a challenge if you are weak in those areas. However, anyone can understand the basics of how things work, and that's the study of chemistry. In a nutshell, the importance of chemistry is that it explains the world around you.
Chemistry Explained
Cooking: Chemistry explains how food changes as you cook it, how it rots, how to preserve food, how your body uses the food you eat, and how ingredients interact to make food.
Cleaning: Part of the importance of chemistry is it explains how cleaning works. You use chemistry to help decide what cleaner is best for dishes, laundry, yourself, and your home. You use chemistry when you use bleaches and disinfectants, even ordinary soap and water. How do they work? That's chemistry.
Medicine: You need to understand basic chemistry so you can understand how vitamins, supplements, and drugs can help or harm you. Part of the importance of chemistry lies in developing and testing new medical treatments and medicines.
Environmental Issues: Chemistry is at the heart of environmental issues. What makes one chemical a nutrient and another chemical a pollutant? How can you clean up the environment? What processes can produce the things you need without harming the environment?
We humans are all chemists. We use chemicals every day and perform chemical reactions without thinking much about them. Chemistry is important because everything you do is chemistry! Even your body is made of chemicals. Chemical reactions occur when you breathe, eat, or just sit there reading. All matter is made of chemicals, so the importance of chemistry is that it's the study of everything.
Importance of Taking Chemistry
Everyone can and should understand basic chemistry, but it may be important for you to take a course in chemistry or even make a career out of it. It's important to understand chemistry if you are studying any of the sciences because all of the sciences involve matter and the interactions between types of matter.
Students wanting to become doctors, nurses, physicists, nutritionists, geologists, pharmacists, and (of course) chemists all study chemistry. You might want to make a career out of chemistry because chemistry-related jobs are plentiful and high-paying. The importance of chemistry won't be diminished over time, so it will remain a promising career path.
Paragraph 1:
Chemistry is important Because it is so fundamental to our world, chemistry plays a role in everyone's lives and touches almost every aspect of our existence in some way.
Paragraph 2:
Chemistry is essential for meeting our basic needs of food, clothing, shelter, health, energy, and clean air, water, and soil.
Paragraph 3:
Even your body is made of chemicals. Chemical reactions occur when you breathe, eat, or just sit there reading. All matter is made of chemicals, so the importance of chemistry is that it's the study of everything.
Paragraph 4:
Chemistry has a reputation for being a complicated and boring science, but for the most part, that reputation is undeserved.
Paragraph 5:
Fireworks and explosions are based on chemistry, so it's definitely not a boring science. If you take classes in chemistry, you'll apply math and logic, which can make studying chemistry a challenge if you are weak in those areas.
Hope it helps :))
How many milliliters of 0.25M H2SO4 can be prepared from 57 mL of a 3.0M solution of H2SO4?
Answer:
Why ? Because 1 molecule of H2SO4 gives 2 H+ ions per molecule while only one H+ ion is required to neutralize 1 molecule of KOH. So, 1 molecule of H2SO4 can neutralize 2 molecules of KOH. Hence, we would require 525 ml of 0.03 M H2SO4 to neutralize 525 ml of 0.06 M KOH. How will we prepare 525 ml of 0.03 M H2SO4 ?
Explanation:
Now, we have 0.025 M H2SO4 and we do not know how much volume we have.
We will use the standard N1 X V1 = N2 X V2 for this calculation.
N1=0.025 M; V1=unknown; N2=0.03 M and V2=525 ml.
So V1= (0.03 X 525)/(0.025) = 630 ml.
According to the molar concentration, 684 ml of 0.25 M H₂SO₄ can be prepared from 57 mL of a 3.0 M solution of H₂SO₄.
What is molar concentration?Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.
The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.
In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.In case of 2 solutions,it is calculated as, M₁V₁=M₂V₂ substitution gives V₁=3×57/0.25=684 ml.
Thus, 684 ml of 0.25 M H₂SO₄ can be prepared from 57 mL of a 3.0 M solution of H₂SO₄.
Learn more about molar concentration,here:
https://brainly.com/question/15532279
#SPJ3
Which of the following statement is wrong?
A)Leaves can make food when there is sunlight
B)Stamen will develop into a fruit
C)Stem helps in the conduction of water
D)Plants need air, water and sunlight to grow
Answer:
C) Stem helps in the conduction of water
Explanation:
It's the xylem and phloem present in the vascular bundles of stems that conduct water and minerals across the plant. Stems bear flowers and fruits in a position that facilitates the processes of pollination, fertilization, and dispersion of seeds. So, stem doesn't help in the conduction of water.
Answer:
the person above is correct
Explanation:
jjecjjeccejec hello good day?
Need help with the balancing one
For a theoretical yield of 5.52 g and percent
yield of 51.7877%, calculate the actual vield
for a chemical reaction.
Answer in units of g.
Answer:
2.85868104g
Explanation:
Actual yield
Theoretical yield x 100 = 51.7877%
So, do the inverse and you get 2.85868104g
5
Increasing the amount of current flowing through a wire strengthens
what? *
O magnetic field
O polarity
O electromagnetism
solenoid
Answer:
Increasing the current would strengthen the
electromagnetisn
What is the charge of cobalt in CoCl2?
Answer:
The oxidation number of cobalt is +2.
Which blocks will move under these conditions and explain
Answer:
Correct: B
Explanation:
The first block wont move because:
Σf=3-3=0N.
The second block will move because:
Σf:5-3=2N (direction to the right).
The third block will move because:
Σf=3N (direction to the right).
What effect does the concentration of reactants have on the rate of a
reaction?
A. Changing the concentration has no effect on the reaction rate.
B. Increasing the concentration decreases the rate of the reaction.
O C. Increasing the concentration increases the rate of the reaction.
O D. The effect of concentration on rate varies within the reaction.
Answer:
C
Explanation:
The answer is C as concentration is a major factor affecting the rate of reaction and it has a direct relationship with the rate of reaction.
The effect that the concentration of reactants has on the rate of a reaction is increasing the concentration increases the rate of the reaction. The correct option is C.
What is a reactant?A reactant is a part of a reaction that is the first part of the reaction. Reactant can be more than one in the reaction. The different reactant reacts, and form a totally different product.
H2 + O2 = H2O
The hydrogen and oxygen are the reactants of the reaction.
Thus, the correct option is C. Increasing the concentration increases the rate of the reaction, as concentration plays a significant role in determining the rate of reaction and is directly related to it.
Learn more about reactants, here:
https://brainly.com/question/14449229
#SPJ5
Calculate:for each object, substitute the values you know into the gravitational potential energy equation to solve for weight. Record each object's weight in the fourth column.
Answere:No sé esto jeje lo siento no soy tonta pero simplemente no sé esto
Explanation:
How does the strength of the forces that hold the basic particles of a substance together relate to the temperature at which the substance changes state? A. Stronger forces between particles means the substance boils at a higher temperature. B. Stronger forces between particles means the substance boils at a lower temperature. C. Weaker forces between particles means the substance boils at a higher temperature. D. Stronger forces between particles means the substance melts at a lower temperature.
Answer:
A. Stronger forces between particles means the substance boils at a higher temperature
Explanation:
Certain forces hold the atoms of different matter together. These forces of attraction between the atoms (basic particle of a substance), however, play a role in how difficult it is to break the substance. The stronger the force, the difficult it is to break the substance and vice versa.
In relation to temperature, a substance with stronger force will require more heat i.e higher temperature to break the atoms. Hence, Stronger forces between particles means the substance boils at a higher temperature. In other words, the stronger the force, the higher the boiling point of that substance and vice versa.
why is atomic radi measured using the nuclues from 2 of the same atoms
Explanation:
Atomic radii is measured using the distance between nucleus of 2 atoms rather than the distance between the nucleus and outermost shell because:
- There is no clear/sharp boundary of the orbital. This is why it is called an electron cloud.
- Also, the exact location of the electron is not known. What is known is the probability of finding the electron there.
Due to this, it is not possible to measure the atomic radii precisely. That's why the distance between the nucleus of two atoms is used.
1CaC2 + 2O2 ---> 1Ca+2CO2
I need the mole to mole ratio.
Can someone help please I will give Brainlyiest
Answer:
See Explanation
Explanation:
moles of NH₃ = 11.9g/17.03 g/mol = 0.699 mole
moles of CN₂OH₄ = 1/2(0.699) mole =0.349 mole
Theoretical yield of CN₂OH₄ = (0.349 mole)(60 g/mole) = 20.963 grams
%Yield = Actual Yield/Theoretical Yield x 100%
= 18.5g/20.963g x 100% = 88.25%
Answer:
same process as last solution I did for you except the mole ratio isn't 1:1 here it is 2:1 so you diveide the moles of NH3 by 2 to get the urea moles
here I got 88.16% yield
Explanation:
What is the pH of a solution with a (H+] = 0.80 M? *Please round your answer to the appropriate number of significant figures. Your answer can be in standard notatic "e" in place of x10.*
Answer:
The pH of a solution with a (H+] = 0.80 M is [tex]9.6 e^{-2}[/tex]
Explanation:
As we know
pH = -[log H+]
Substituting the value of H+ ion concentration in the above equation, we get -
pH = -log [0.80]
pH [tex]= -[-0.096] = 0.096 = 9.6 e^{-2}[/tex]
If it takes 38.70 cm^3 of 1.90M NaOH to neutralize 10.30cm^3 of H2SO4 in a battery. What is the concentration of the H2SO4?
Answer:
3.57 M
Explanation:
The reaction that takes place is:
2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂OFirst we calculate how many NaOH moles reacted, using the given concentration and volume:
38.70 cm³ = 38.70 mL1.90 M * 38.70 mL = 73.53 mmol NaOHThen we convert NaOH moles into H₂SO₄ moles, using the stoichiometric coefficients:
73.53 mmol NaOH * [tex]\frac{1mmolH_2SO_4}{2mmolNaOH}[/tex] = 36.765 mmol H₂SO₄Finally we calculate the concentration of H₂SO₄:
36.765 mmol H₂SO₄ / 10.30 mL = 3.57 MWhat is the molar mass of H3PO4? (atomic mass: H = 1.01, P = 30.97, O = 15.99)
Answer:
98
Explanation:
molar mass of H3PO4=(3×1)+(31)+(4×16)=3+31+64=98
Select the statements that are true about electronegativity between elements,
and their type of bond.
A. If the difference is over 1.7, an ionic bond will form.
B. If the difference in electronegativity is from 0.6 to 1.7, the bond
will be nonpolar and covalent.
C. If the difference in electronegativity is 2 to 2.5, the bond will be
nonpolar covalent.
Answer:
a
Explanation:
if the difference is over 1.7, an ionic bond will form
What happens to particles of a substance as its temperature increases?
A the average kinetic energy increases
B the average kinetic energy decreases
C the average kinetic energy stays the same
D nothing happens
Answer:
A. the average kinetic energy increases
Explanation:
temperature is a measure of the average kinetic energy of the particles in a sample of matter
2. Name each of the following ionic compounds A. K2O B. Cacl2. C. Mg3N2 D. NaCIO E. KNO3
Ionic compound K₂O is potassium superoxide. CaCl₂ is calcium chloride. The compound Mg₃N₂ is magnesium nitride and NaClO is sodium hypochlorite and KNO₃ is potassium nitrate.
What are ionic compounds?Ionic compounds are formed between metals and non-metals. They are bonded by lose of electrons from the metal to the non-metals. An ionic compound is named starting with the cation and then the anionic part is named second with the suffix "ide" , "ate" , "ite" etc.
The compounds with the general formula M₂O are called super oxides. K₂O is called potassium superoxide or dipotassium oxide.
The compound, CaCl₂ is named as calcium chloride. The subscripts in formula are the number of each atoms in the compounds.
Similarly Mg₃N₂ is named as magnesium nitride and KNO₃ is called potassium nitrate. The compound NaClO is named as sodium hypochlorite.
To find more on ionic compounds, refer here:
https://brainly.com/question/9167977
#SPJ5
Practice
Write an equation for each of the described reactions. Include subscripts, and state of matter notation as needed.
Don't forget about the diatomic elements!
*Complete this on a separate sheet of lined paper and attach this to the GCR assignment.
1. Solid lithium reacts with water to produce hydrogen gas and a solution of lithium hydroxide.
2. Solid sodium reacts with gaseous chlorine to produce sodium chloride.
3. Solid calcium carbonate breaks down into carbon dioxide gas, oxygen gas, and solid calcium.
4. Solid iron(II) sulfate and a solution of barium chloride react to form solid barium sulfate and a solution of
iron (II) chloride.
5. Solutions of hydrochloric acid and sodium hydroxide react to produce liquid water with sodium chloride
dissolved in it.
Answer and Explanation:
For each reaction, it is useful to detail which are the reactants (left side of the equation) and which are the products (right side of the equation), to deduce the chemical formulas.
1. Solid lithium reacts with water to produce hydrogen gas and a solution of lithium hydroxide.
Reactants: lithium element in solid-state (Li(s)) and water (H₂O) in the liquid-state. Products: hydrogen gas which is a diatomic molecule (H₂) and lithium hydroxide, which is a base formed by lithium cation Li⁺ and OH⁻ anion (LiOH).
Li(s) + H₂O(l) → H₂(g) + LiOH(aq)
2. Solid sodium reacts with gaseous chlorine to produce sodium chloride.
Reactants: sodium metal in solid-state (Na(s)) and chlorine which is a diatomic gas (Cl₂). Products: sodium chloride, which is a salt formed by sodium and chloride together (NaCl).
Na(s) + Cl₂(g) → NaCl(s)
3. Solid calcium carbonate breaks down into carbon dioxide gas, oxygen gas, and solid calcium.
It is a decomposition reaction, so we have only one reactant: calcium carbonate, which is a salt composed of carbonate anion (CO₃⁻²) and calcium ion (Ca²⁺). Products: carbon dioxide (CO₂), oxygen gas which is diatomic (O₂), and solid calcium (Ca(s)).
CaCO₃(s) → CO₂(g) + O₂(g) + Ca(s)
4. Solid iron(II) sulfate and a solution of barium chloride react to form solid barium sulfate and a solution of iron (II) chloride.
Reactants: iron(II) sulfate which is an ionic compound formed by the sulfate ion (SO₄²⁻) and iron ion (with two positive charges: Fe²⁺), and barium chloride which is a salt of barium ion (Ba²⁺) and two chloride ions (Cl⁻). Products: the salts formed by ion exchange, barium sulfate (BaSO₄), and iron (II) chloride (FeCl₂).
FeSO₄(s) + BaCl₂(aq) → BaSO₄(s) + FeCl₂(aq)
5. Solutions of hydrochloric acid and sodium hydroxide react to produce liquid water with sodium chloride dissolved in it.
It is the classical neutralization reaction. Reactants: hydrochloric acid (HCl) and the strong base sodium hydroxide (NaOH). Products: water (H₂O) and the salt formed by the anion provided by the acid (Cl⁻) and the cation provided by the base (Na⁺): NaCl.
HCl(aq) + NaOH(aq) → H₂O(l) + NaCl(aq)
Two students pull a box with force of 100 N to the left and 200 N to the right.
What is the net force and direction in which the box moved?
Answer:
net force is 100 N and direction is right
Explanation:
After Dalton's proposed atomic theory, several atomic models were developed. Which model was the first propose the existence of
small, dense nucleus?
Answer: Rutherford's model was the first propose of the existence of small, dense nucleus's.
Explanation: The atom, as described by Ernest Rutherford, has a tiny, massive core called the nucleus. The nucleus has a positive charge. Electrons are particles with a negative charge. Electrons orbit the nucleus. The empty space between the nucleus and the electrons takes up most of the volume of the atom.
Answer: Here is the correct image of the first atomic model it's in the picture!
Explanation: I did it on USA Test Prep to see which one is right
What is the definition of an alternative acid?
alternative acids are more cost-effective and allow for flavor expression through nontraditional methods and ingredients, making for increased versatility.
I will mark somebody brainliest
OMG PLEASEEEE HELPPPPPPPPPPP!!!!!!!!!!!
Answer:
the second one
Explanation:
THE answers is b
Please help!!! What is electrolysis?
Explanation:
plzz tell me the ans even i also want to know plzzzz someone say ans
Answer:
electrolysis is a procedure that uses direct electric current to achieve an otherwise non-spontaneous chemical reaction and is important in the separation of elements from naturally occurring