Answer:
Chemical changes cause a substance to change into an entire substance with a new chemical formula. Chemical changes are also known as chemical reactions. The “ingredients” of a reaction are called reactants, and the results are called products.
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1. Calculate the average atomic mass of iron if its abundance in nature is 15%-iron-55 and
85% iron-56
The average atomic mass of iron : 55.85 amu
Further explanationThe elements in nature have several types of isotopes
Isotopes are atoms whose no-atom has the same number of protons while still having a different number of neutrons.
An atomic mass unit = amu is a relative atomic mass of 1/12 the mass of an atom of carbon-12.
The 'amu' unit has now been replaced with a unit of 'u' only
Atomic mass is the average atomic mass of all its isotopes
atomic mass X = mass isotope 1 . % + mass isotope 2.% ...
The average atomic mass of iron
[tex]\tt =0.15\times 55+0.85\times 56\\\\=\boxed{\bold{55.85~amu}}[/tex]
The average atomic mass of iron : 55.85 amu
Calculation for average atomic mass:Isotopes are atoms whose atoms have the same number of protons while still having a different number of neutrons.
An atomic mass unit = amu is a relative atomic mass of 1/12 the mass of an atom of carbon-12.
The 'amu' unit has now been replaced with a unit of 'u' only
Atomic mass is the average atomic mass of all its isotopes.
Atomic mass X = mass isotope 1 * Mas % + mass isotope 2* Mass %
The average atomic mass of iron:
=0.15 * 55 + 0.85 * 56
=55.85 amu
Thus, the average atomic mass of iron : 55.85 amu
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Which description applies to a physical property? Choose the correct answer
O depends directly on the amount of the substance present
O examines changes in the composition and structure of matter
O measured or observed without changing the identity and composition of matter
O determined by changing the identity of a substance and observing how it reacts
Answer:
the third one, measured or observed without changing the identity and composition of matter. because physical property does not under go any change but can be put back.
Silver is a white metal that is an excellent conductor. Silver tarnishes when exposed to air and light. The density of silver is 10.49 g/cm3. The melting point is 962oC and the boiling point is 2000oC. A chemical property of silver is A) density. B) melting point. C) tarnishes in air. D) that it is a conductor.
Answer:
c tarnishes in air
Explanation:
After silver has been exposed to air that contains sulphur gases, discoloration would occur. there would be darkening that is caused by the reaction with gases.When any silver object tarnishes, it brings about a disfiguring of that object. Hydrogen sulphide would be needed for this to happen. silver sulphide is black and a if a thin layer should form on any surface, it ill darken it. This is what we refer to as tarnishing.
Answer:
c
Explanation:
it tarnishes in air
Describe the main differences beA human cell has 46 chromosomes. At the end of mitosis, there are two cells, each with 46 chromosomes, for a total of 92 chromosomes split between both cells.
Which statement describes meiosis in a human cell?
At the end of meiosis, there are two cells, each with 46 chromosomes, for a total of 92 chromosomes split between both cells.
At the end of meiosis, there are four cells, each with 23 chromosomes, for a total of 92 chromosomes split between the four cells.
At the end of meiosis, there are four cells, each with 46 chromosomes, for a total of 184 chromosomes split between the four cells.
At the end of meiosis, there are two cells, each with 23 chromosomes, for a total of 184 chromosomes split between both cells. tween meiosis and mitosis.
Answer:
At the end of meiosis, there are four cells, each with 23 chromosomes, for a total of 92 chromosomes split between the four cells.
Explanation:
During meiosis, a diploid cell (46 chromosomes) replicates its DNA (making 92 chromosomes) then undergoes two cell divisions to generate four haploid cells (23 chromosomes).
These haploid cells are the gametes which, during fertilization, fuse to become a zygote with 46 chromosomes.
Answer:
the person above me is correct.
Explanation:
A lump of chromium (Cr) has a specific heat of 0.448J/g℃. It is heated to a temperature of 89.5℃ and placed into a calorimeter with 75.2 mL of water at 20.5℃. After stirring, the final temperature of the water, Cr metal, and calorimeter is 27.4℃. What is the mass of Cr metal?
Answer:
Mass of Cr= 78 g
Explanation:
Given data:
Specific heat of Cr = 0.448 j/g.°C
Initial temperature of Cr lump = 89.5°C
Mass of water = 75.2 mL or 75.2 g
Initial temperature of water = 20.5°C
Final temperature of water = 27.4°C
Mass of Cr = ?
Solution:
when we placed the lump of Cr metal into water heat lost by limp is equal to the heat gain by water.
Specific heat capacity of water is 4.184 j/g.°C
Q = mcΔT
Q = 75.2 g× 4.184 j/g.°C × (27.4°C - 20.5°C)
Q = 2171 J
Heat lost by Cr lump is -2171 J. Now we will calculate the mass of Cr.
Q = mcΔT
-2171 J = m ×0.448 j/g.°C × ( 27.4°C- 89.5°C)
-2171 J = m × -27.821 j/g
m = -2171 J/-27.821 j/g
m = 78 g
What is the mass of 4.39 mol Na?
Answer:
101 g Na
Explanation:
To convert between moles and grams, you have to use the molar mass of the substance. The molar mass of sodium is 22.99 g/mol. You use this as the unit converter.
[tex]4.39molNa*\frac{22.99gNa}{1molNa} = 100.9261gNa[/tex]
Round the number to the lowest number of significant figures; 101 g Na.
The mass of 4.39 moles of sodium (Na) is 100.97grams.
HOW TO CALCULATE MASS:The mass of a substance can be calculated by multiplying the number of moles in the substance by its molar mass. That is;Mass = no. of moles × molar mass
According to this question, there are 4.39 moles of Na. The molar mass of Na is 23g/mol.Mass of Na = 4.39 × 23
Mass of Na = 100.97grams.
Therefore, mass of 4.39 moles of sodium (Na) is 100.97grams.
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Joy mixed baking soda and vinegar for her volcano model. She saw lots of bubbling and fizzing. What can she infer happened
A chemical change
A change in state liquid to solid
Matter was created
A physical change
Answer:
a chemical change
Explanation:
bubbles formed
Answer:
Explanation:
✔︎A chemical change
✖︎wich is D
would be ur answer
Explanation:
❐A chemical change happens when one chemical substance is transformed into one or more different substances, such as when iron becomes rust. Chemical changes occur through the process of chemical reactions, and the resulting substances have different properties because their atoms and molecules are arranged differently.
CAN I PLZ GET MARK AS THE BRAINLIEST? ")
8. Which word best describes the element in box number 2?
a а Brittle
b Gas
С Semiconductor
d. Shiny
Answer:
gas
Explanation:
i think it might be gas
The compound, BeCl2, would be formed by
a. The sharing of all electrons
b. The transfer of all electrons
c.
The transfer of valence electrons
d. The sharing of valence electrons
Answer:
The sharing of valence electrons
Explanation:
A covalent bond is formed when two or more atoms share valence electrons.
In BeCl2, electrons are shared between the beryllium atom and two chlorine atoms.
Owing to the large difference in electronegativity between the two elements, the bond is polar covalent.
Name the laws for 1,2, and 3
Answer:
1. Boyle's law
2. Charle's law
3. Ideal Gas law
Explanation:
When comparing bromine to chlorine, bromine has
A. Fewer protons in its nucleus.
B. A weaker effective nuclear charge
C. More valence electrons
D. More electron shielding
Explanation:
I'm pretty sure the answer is D
apples cost $1.75 per pound
What conversion factor could be used to determine how many pounds of apples could be bought for $10.00 ?
Answer: my opinion is about 5 pounds of apples that you can get with $10
Explanation:
srry if im wrong
Aquanauts explore the area called?
Answer:
Inner space
Explanation:
I hope this helps
Chloe is training for her first half-marathon, which requires her to run 21.1 km. Before she runs, she carefully chooses the foods that will give her the energy her body requires for the race. She stands still at the starting line, then she starts running, her body warming up as she runs. Which three energy transformations take place in this example? Potential energy to kinetic energy Chemical energy to thermal energy Chemical energy to kinetic energy Mechanical energy to chemical energy
Answer:
The transformation is of chemical energy (use the ATP molecule as a resource) which is then transformed into mechanical energy (muscle contraction) and finally transformed into thermal energy (increase in body temperature, or sweating)
Explanation:
Energy is never lost, it is always transformed, that is why energy is yielding electronic movement and expressing itself in different ways, first as chemical energy, then as mechanical energy, and lastly as thermal energy.
It is important to clarify that the energy source of all this transformation is food and energy reserves.
Each of the four liquids had the same volume, why don’t
they each have the same density?
Key concepts
Physics
Chemistry
Density
Liquids
Introduction
You probably know that when solid objects are placed in liquid, they can sink or float. But did you know that liquids can also sink or float? In fact, it is possible to stack different layers of liquids on top of one another. The key is that all the different layers must have different densities. You can stack them by picking several liquids with a range of densities or by varying the density of one liquid by adding chemicals such as sugar or salt to it. If you choose colored liquids or add food coloring to each layer, you can even create a whole rainbow of colors in one single glass! Want to see for yourself? In this science activity you will stack several liquids—one by one—and create a colorful density column!
Background
Whether an object sinks or floats depends on its density compared with the density of the liquid into which it is dropped. All types of matter—solids as well as liquids—are made up of many different atoms. Depending on the mass of these atoms, their size and the way they are arranged, different substances will have different densities. The density is characteristic for each individual compound and defined as the mass of a compound divided by its volume. In other words, the more matter there is in a certain amount of volume, the denser a substance is. One cubic centimeter of rock, for example, is much heavier than a cubic centimeter of wood. This is because there is much more matter in the same volume of rock compared with the wood.
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Liquids can also have different densities. Freshwater, for example, has a density of about one gram per cubic centimeter at room temperature. Any compound—liquid or solid—that has a higher density than water will sink whereas substances with a lower density than that will float. You can test that for yourself by gathering several liquids that you have in your kitchen such as vegetable oil, corn syrup, dishwashing soap, water, rubbing alcohol and more. Which one of these do you think will sink or float in water? Find out in this activity!
Materials
Glass or cup
Water
Food coloring
Scissors
Rubber band (wide)
Small piece of wax
Popsicle stick
At least two small, clear jars or transparent mini cups (two ounces) with lids
Permanent marker
Masking tape
Three tablespoons
Dark corn syrup
Vegetable oil
Penny
Paper towels
Rubbing alcohol, dishwashing soap and other liquids (optional)
Sugar (optional)
Preparation
Gather all your materials at a workspace that can tolerate spills of all the liquids.
Fill a cup with tap water and add a couple of drops of food coloring to the water.
Ask an adult to help you cut and prepare small pieces (about 0.5 by 0.5 centimeter) of the rubber band, the popsicle stick and the wax.
Place the two empty jars in front of you (without the lids) and label them “1” and “2” with a piece of tape and the permanent marker.
Procedure
Take a clean tablespoon and pour two tablespoons of corn syrup in jar 1.
With the second tablespoon, carefully pour two tablespoons of colored water into jar 1 on top of the corn syrup. What happens to the water on top of the corn syrup? Does it mix or stay separate?
Use the third clean tablespoon to pour two tablespoons of vegetable oil in jar “1” on top of the colored water. Do you see mixing of the liquids? What happens to the oil? Does it float on top or sink to the bottom?
Now take empty jar 2 and add the same liquids—but in reverse order. Start by pouring in two tablespoons of vegetable oil.
A student observes that instant tea dissolves more rapidly in a cup of 250 mL of stirred hot water than in a cup of 250 mL of stirred cold water. Which is the most relevant hypothesis that the student could develop based on this observation?
A.
Volume affects the rate that instant tea dissolves in a solvent.
B.
Temperature affects the rate that instant tea dissolves in water.
C.
Stirring affects the rate that instant tea dissolves in water.
D.
Pressure affects the rate that instant tea dissolves in water.
Please answer my question!
Answer:
B
Explanation:
In this question, there is no mention of pressure, so we can eliminate answer D. In both cups, it mentions they contain 250 mL of water and both are stirred, so these would be constants. The only difference between the cups is temperature, so temperature must affect the rate that instant tea dissolves in water. Therefore the answer is B.
An object has 15 grams of atoms and displaces 2.5 mL of water when dropped into a cylinder. What is the objects density... HELP IM IN CLASS RN AND I NEED ANSWERS ASAP, grades are due in couple hours
Answer:
6g/mL
Explanation:
The density, which is the mass per unit volume of an object, can be calculated using the formula;
D= m/v
Where; D = density (g/mL)
M = mass of substance (g)
V = volume (mL)
In this question, the object's mass = 15g, volume of water= 2.5 mL, d =?
Therefore,
Density = 15/2.5
Density = 6 g/mL
The object's density is 6g/mL
In this chemical formula: 3NH4 (ammonium) This chemical formula means there are 3 _____________ ___________, and 4 __________ ________ in each molecule.
Answer:
hope it helped you
Explanation:
3 atoms of nitrogen and 4 atoms of hydrogen in each molecule
The chemical formula 3NH4 means there are 3 atoms of nitrogen and 4 atoms of hydrogen in each molecule.
What are chemical reaction?Chemical reaction is defined as a process in which one or more substances, the reactants, are converted into one or more different substances, the products.
A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.
There are five main types of reactions.
Combination reaction - A combination reaction is a reaction in which two or more substance combine to form a single new substance also known as synthesis reaction.Decomposition reaction - A decomposition reaction is a reaction in which a compounds break down into two or more simpler substance.Single replacement reaction - A single replacement reaction is a reaction in which one element replaces a similar element in a compound.Double replacement reaction - A double replacement reaction is a reaction in which the positive or negative ions of to ionic compounds exchange places from two new compound.Combustion reaction - A combustion reaction is a reaction in which a substance reacts with oxygen gas, releasing energy in the form of heat and light.Thus, the chemical formula 3NH4 means there are 3 atoms of nitrogen and 4 atoms of hydrogen in each molecule.
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what is the identity of the element that produced the unknown emission spectrum
Answer:
The emitted light can be observed as a series of colored lines with dark spaces in between; this series of colored lines is called a line or atomic spectra.
Explanation:
Which food molecules are outside of the tube
Answer:
Absorption
Explanation:
I think from Quizlet
By what process do small molecules move into cells?
Answer:
small molecules move into the cell, Then it is by diffusion or facilliated diffusion.
Which of these statements describes a chemical property?
Answer:
it rusts when exposed to air
Answer:
A
Explanation:
he descriptions below explain two ways that water is used by plants on a sunny day.
I. In a process called transpiration, some liquid water in leaves changes to water vapor. The water vapor is released into the air through tiny pores in the leaves. This allows more liquid water from the soil to be pulled up the roots and stem to replace water lost from the leaves.
II. Plants use some of this water in leaves in a process called photosynthesis. During photosynthesis, water and carbon dioxide break apart and recombine to form two new substances, oxygen and glucose.
Based on the above description of transpiration and photosynthesis, which type of change happens to water during each process?
In transpiration, because some of its properties change, water undergoes a physical change but keeps its identity. In photosynthesis, because its identity changes, water undergoes a chemical change.
In transpiration, because some of its properties change, water undergoes a chemical change but keeps its identity. In photosynthesis, because its identity changes, water undergoes a physical change.
In transpiration, because its physical properties change, water undergoes a physical change and loses its identity. In photosynthesis, because it keeps its identity, water undergoes a chemical change.
In transpiration, because its chemical properties change, water undergoes a chemical change and loses its identity. In photosynthesis, because it keeps its identity, water undergoes a physical change.
Mark this and return
Answer:number 2
Explanation: because thats how it works
Explanation:
The diagram shows a model of an animal cell. Explain how you'd modify the model to show the structures in a plant cell.
Answer:to show the structures of a plant cell,add a cell wall around the membrane and increase the size of the vaculoe insidethe cell, draw green ovals to represent chloroplasts.
Explanation:
How are mineral characteristics different from mineral properties?
Answer:
The physical properties of minerals are related to their chemical composition and bonding. Some characteristics, such as a mineral's hardness, are more useful for mineral identification.
Explanation:
Answer:
Explanation:
mineral properties are what it is made if the characteristics are what it looks like. Like is it shiny, hard, smooth. those are characteristics.
How will you increase the solubility of a gases in a liquid solvent?
A. Decrease the Temperature
B. Decrease the Pressure
C. Increase the Temperature
D. Increase the Pressure
Answer:
increase the temperature
Explanation:
The solubility of a gas in a liquid will increase if: Lower the temperature of the solution , and therefore, lower the kinetic energy of the gaseous particles so they can escape the liquid phase less often.
7. Which liquid caused the egg to shrink? *
(1 Point)
a. Vinegar
b.Water
c.Corn Syrup
Answer:
c.corn syrup
the egg shrinks due to osmosi.
Using triangulation which point is the earthquakes epicenter?
Answer:
free points aye
Explanation:
Answer: 3
Three is where the earthquakes epicenter is.
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Why are small quantities of chlorofluorocarbons so harmful to the ozone layer? a. The chlorofluorocarbons act like ultraviolet radiation causing large amount of ozone to be produced. b. The chlorine from the chlorofluorocarbons reacts with free molecules of oxygen causing a stop in ozone production. c. Free oxygen atoms can replace the chlorine in chlorine monoxide, releasing a free atom of chlorine which can then recombine with an oxygen atom in ozone, destroying more ozone. d. Chlorofluorocarbons absorb ultraviolet radiation, preventing the formation of ozone.
Answer:
Why are small quantities of chlorofluorocarbons so harmful to the ozone layer? Free oxygen atoms can replace the chlorine in chlorine monoxide, releasing a free atom of chlorine which can then recombine with an oxygen atom in ozone, destroying more ozone.
Explanation:
The statement for small quantities of chlorofluorocarbons so harmful to the ozone layer is "Free oxygen atoms can replace the chlorine in chlorine monoxide, releasing a free atom of chlorine which can then recombine with an oxygen atom in ozone, destroying more ozone."
What is ozone layer?The ozone layer is a thin layer of air in the Earth's atmosphere that absorbs nearly all of the sun's damaging UV radiation.
What is CFCs?CFCs (chlorofluorocarbons) are harmless and nonflammable compounds made up of carbon, chlorine, and fluorine atoms.
The earth's protective ozone layer is destroyed by chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and halons, which shield the earth from damaging ultraviolet (UV-B) rays released by the sun. CFCs and HCFCs also warm the earth's lower atmosphere, causing global climate change.
When some substances are exposed to high UV radiation in the stratosphere, they emit chlorine or bromine. Ozone-depleting chemicals are compounds that contribute to ozone depletion (ODS). Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), carbon tetrachloride, and methyl chloroform are examples of ODS that produce chlorine. Halons and methyl bromide are two ODS that emit bromine.
Because there isn't much ozone in the atmosphere, what little there is is critical for protecting the Earth's surface from excessive UV light from the Sun. It turns out that it reacts with chlorine, which means that chlorine effectively eliminates ozone.
When the chlorine in CFCs combines with ultraviolet light, it releases chlorine, which then reacts with ozone, reducing the protection humans get from ultraviolet light, allowing more CFCs to release chlorine, and so on. Multiple ozone molecules will interact with one free chlorine atom, which is free because UV light has hit the CFC molecule. As a result, the damage it can cause is likely to be significantly more than you might imagine.
Hence the correct option is c.
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Reggie suddenly decided to drive to the Grand Canyon, because he had never seen it. He didn't even have a map showing him how to get there! Reggie made a(n) _____. a. routine decision b. impulse decision c. daily decision d. regular decision Please select the best answer from the choices provided A B C D
Answer:
b. impulse decision
Explanation:
In this scenario, Reggie suddenly decided to drive to the Grand Canyon, because he had never seen it. He didn't even have a map showing him how to get there! Reggie made an impulse decision.
An impulse decision can be defined as a type of decision an individual makes without having a clear thought about the decision. Thus, an impulsive decision is strictly based on an individual's inclination, instinct, whim or sudden desire to do something.
This ultimately implies that, decisions that are made spontaneously without due diligence and considerations refer to an impulse decision.
Hence, Reginald's decision is an impulse decision because he suddenly decided to drive to go see a place (Grand Canyon) he hasn't seen before, even though he had no map to use as a guide or direction.
Answer: b
Explanation: