Answer: Physical change
Explanation: Quite simple as the starfish opening a clam would mean the starfish is physically changing the clams look.
A starfish opening a clam is a chemical change because opening a clam will be done by the secretion of saliva from the starfish that will open the clam.
What are physical and chemical changes?The term “physical change” refers to a change in an object's appearance. When there is a change in the surroundings of the object, such as a rise in temperature or pressure, a physical change takes place.
When candles are burned, the wax melts, but as soon as the temperature drops, the wax hardens and solidifies once more.
A chemical change is a change that can be done by a reaction between two substances that can come in contact. A starfish is opening a clam to eat the clam, it can be done by the mouth which secretes an enzyme that will open the clam.
Thus, a starfish opening a clam is a chemical change.
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What is the mass number of an isotope that has two neutrons
Answer:
mass number = 3
Explanation:
Hydrogen is the only chemical species that has an isotope with 2 neutrons. Since all hydrogen atoms only have 1 proton, the mass number of hydrogen isotope with 2 nuetrons would be 3. The mass number is equal to number of protons + neutrons (+ electrons but they have virtually no mass so they can be excluded).
Please help ASAPPPPP
how many grams of oxygen are in 180 g of water
Answer:
The balanced equation tells you 1 mole of oxygen gives you 2 moles of water, so you will get 10 moles of water, which is 180 g. 5 moles oxygen *(2-mole water / 1-mole oxygen) * 18 g / mol water = 180 g water.
How do I convert 35 degrees Celsius into Fahrenheit?.
Answer:
Multiply the temperature in degrees Celsius by 2, and then add 30 to get the estimated bro.
Explanation:
Constellations pls they are easy but not many photos are the same pls thank you
Answer:
What I would do is search about Constellations and the name of them. And where they are located.
Explanation:
hope this helps
how the nervous system organs are interrelated (with the body as a whole)
The brain sends messages traveling the spinal cord to peripheral nerves through the body that serve to control the muscles and central organs. The relation to the body and large as differently recognized from the mind nervous system is made of specialized cells transmitting nerve impulses; a nerve cell. The Central nervous system with the parts of the body that interact within the outside world.
consider the two setups below. in setup 1, conducting bodies A and B have the same temperature, while in setup 2, conducting bodies C and D have different temperatures-C is hotter than D.All the bodies are made of the same material.
a. will heat transfer occur in both setups?why?
b. in the setup(s) where heat transfer can occur, draw an arrow in the diagram(s) to represent the direction of heat flow between the two bodies.
c. will heat perpetually flow between the two bodies in each setup?why?
The heat transfer will only occur in setup 2 and heat will only flow from C to D.
Heat energy
In a mixture between two substances of different temperatures, there is heat transfer, in which the one with a lower temperature receives this heat and the one with a higher temperature loses the heat.
In a system, the value of heat lost and received is equal.
So, heat will only flow in setup 2 since it is the only one that has two bodies with different temperatures, and it will flow from C to D because C has a higher temperature.
The representation of heat transfer can be done as follows:
C ⇒ D
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Covert 67cm to km write ur answer in scientific notation
Answer:
67 × 10⁻⁵ = 0.00067
A 1250.0 g piece of aluminum at -35.0°C receives 72.41 kJ of heat. If aluminum has a heat capacity of 0.90
calculate AT in °C. The melting point of Al is 660°C. Your answer must have the correct number of sig figs.
g.K
AT =
°C
This problem is providing the mass, specific heat and melting point of aluminum and the amount of heat it receives in a heating process so it asks for the change in its temperature, which results in 64.36 °C.
CalorimetryIn chemistry, one can perform calorimetry calculations with the widely-known heat equation relating mass, specific heat, temperature and heat:
[tex]Q=mC\Delta T[/tex]
Thus, when having 1250.0 g of aluminum at -35.0 °C and supplying 72.41 kJ (72,410 J) of heat, we will be able to solve for the change in temperature by solving for it in the previous formula:
[tex]\Delta T=\frac{Q}{mC} \\\\\Delta T=\frac{72,410J}{1250.0g*0.90\frac{J}{g\°C} } \\\\\Delta T=64.36\°C[/tex]
Which is not as high as for it to provoke a melting change, with the correct significant figures as 0.90 do not contribute to this for being a theoretical number.
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How can we separate a homogeneous mixture?
Methods:
evaporation
distillation
chromatography
Explanation:
There are three common methods to separate a homogeneous mixture, which are evaporation, distillation, chromatography.
Lets look more deeper into the best method:
Evaporation is typically considered to be the best method where we heat the mixture until no more liquid remains. The salts will be visible and left out, separated.
In one or two sentences, describe what would happen to the frequency of this wave if the wavelength is increased to 10m but the speed stays the same at 600 m/s
When the wavelength increases, wave frequency decreases so if the if the wavelength is increased to 10m then the frequency will be decrease at the same rate.
Relationship of wavelength and frequencyFrequency and wavelength have inverse relationship to each other. The wave with the greatest frequency has the shortest wavelength. If the frequency increases twice it means one-half the wavelength so we can conclude that if the wavelength is increased to 10m then the frequency will be decrease at the same rate.
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If water is added to 50 ml of a 0. 04 M solution so that it fills a 200 ml beaker, what is the final concentration? M.
Which of these is an example of the conversion of elastic potential energy into kinetic energy?
Answer:
a rubber band
Explanation:
5.00 g of solid silver nitrate AgNO3 is added to 100ml of deionized H2O to make a substance that can test the presence of chlorine in water. Identify in the word problem each of the following: (1pt each).
What is the solvent?
What is the solute?
What is the solution?
The solvent will be the deionized water, the solute will be the AgNO3, and the solution is the substance that can test the presence of chlorine water.
Solvent, solute, and solutionA solvent is a liquid that can dissolve other substances
A solute is a solid capable of dissolving in relevant solvents
A solution is a mixture of solvent and dissolved solutes
In this case, the solvent that is capable of dissolving the solute is deionized water. The solute is the silver nitrate, while the solution would be a solution of silver nitrate.
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in general, nonmetals are:
Guys i need your advice i got D+ in chemistry should i tell my parents?
Answer:
yes
Explanation:
its the correct thing to do
Answer keeps getting marked wrong! need some guidance..
what is the mass in grams of 8000. mL of alcohol is the density of 0.79 g/mL? Use sig figs please
Answer:
Explanation:
The volume of ethanol is V =8000 ml
The density if the ethanol is ρ=0.79g/mL
density = mass/volume which can be rewritten as
mass = density x volume
Using given volume and density, the mass of ethanol is computed
mass = (8000 mL) x (0.79 g/mL)
mass = 6320 g
Thus, the mass of ethanol is 6320 grams.
What is the product(s) in the reaction below?
CH4(g)202(g)→ CO2(g) + 2H20(g)
Answer:
It is an example of Exothermic reaction.
Explanation:
It leads to release of HEAT as can be seen water is given in gaseous form.
What is the limiting reactant if 12 moles of p4 react with 15 moles of o2?.
Answer:
see explanation
Explanation:
To determine limiting reactant divide mole quantities of reactants by the respective coefficient in the balanced equation. The smaller value is the limiting reactant.
P₄ + 5O₂ => 2P₂O₅
12/1 = 12 15/5 = 3
O₂ is the limiting reactant. P₄ will be in excess when rxn stops.
You recrystallize 2.1 g of an impure sample and recover 0.98 g. What is your percent recovery rounded to the tenths place
Answer:
c
Explanation:
The percent yield or percent recovery after recrystallization of the sample is 46.67%
What is percent yield?Percent yield is defined as the ratio of actual yield to the theoretical yield multiplied by 100. If the actual and theoretical yield are same then the percent yield is 100%.If actual yield is less than the theoretical yield then the percent yield is less than 100%.Reason of this condition arising is the incompletion of reaction or loss of sample during recovery process.
In cases where percent yield is over 100% it indicates that more sample is recovered than the predicted amount.This condition arises when there are other simultaneous reactions taking place leading to the formation of product. It can also arise if there is incomplete removal of impurities from the sample .
In the given example,percent yield or percent recovery is calculated as,
percent yield=recovered yield/recrystallized yield×100
=0.98/2.1×100=46.67%
Hence, the percent yield or recovery is 46.67%.
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Which of these are examples of negative tropism? (Select all that apply.)
a plant’s roots growing down into the soil due to gravitropism
a plant’s stem growing upward out of the ground due to gravitropism
a plant’s leaves growing toward the direction of the sun due to phototropism
a plant’s roots growing toward a water source due to hydrotropism
a plant’s leaves growing away from the sunlight due to phototropism
a plant’s roots growing away from a water source due to hydrotropism
Answer:a plant’s stem growing upward out of the ground due to gravitropism
a plant’s leaves growing away from the sunlight due to phototropism
a plant’s roots growing away from a water source due to hydrotropism
Explanation:
5.00 g of solid silver nitrate AgNO3 is added to 100ml of deionized H2O to make a substance that can test the presence of chlorine in water. Identify in the word problem each of the following: (1pt each).
What is the solvent?
What is the solute?
What is the solution?
Answer:
The solvent is deionised water
The solute is AgNO3
The solution is [Ag(aq) + NO3(aq)-]
Explanation:
This is because it contains no ions which would otherwise react with AgNO3 thus AgNO3 just disolves releasing free Ag+ and NO3- . The resiltant solution can test for Cl presenceAgNO3 is a soluble salt in water thus disolves in waterAgNO3 disolves releasing free ions which can be called ionisationAs astronomers have learned more about the structure of the sun, they have found that it
As astronomers have learned more about the structure of the sun, they have found that sun has six layers.
Structure of sun
The structure of the sun consist of six layers. The corona, chromosphere, and photosphere are the three layers present in the outer layer of the sun whereas the other three layers i.e. convective zone, radiative zone, and core, comprise the inner layers.
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How many moles of nitrogen are needed to inflate a 58 L airbag? How much sodium azide is needed to decompose this amount of nitrogen. I will give brainliest.
Answer:
A handful (130 grams) of sodium azide will produce 67 liters of nitrogen gas--which is enough to inflate a normal air bag. 0.03 SECOND is all it takes to inflate an air bag.
Based on the balanced equation reactants to product ratio are 2:3 for Azide: Nitrogen gas. This means for every 3 moles of Nitrogen gas produces, 2 moles of Sodium Azide are needed
Explanation:
Help!!! Two students measure and record the volume of the same sample of water in the graduated cylinder shown below. The first student recorded the volume as 16.0 mL and the second student recorded the volume as 16 mL.
Which statement best identifies and explains the correct measurement?
According to accuracy concept,statement A best identifies and explains the correct measurement.
What is accuracy?
Accuracy in terms of chemistry can be defined as to how close a measurement is to the true value.There are three types of accuracy:
1) Point accuracy-It means accuracy is present at that point of scale only.It does not give any information about the accuracy of the instrument.
2)Percentage of true value--It is the accuracy which is determined by identifying accuracy of the instrument and comparing it with the measured true value.
3)Percentage of scale range- It is the accuracy which determines accuracy of the measurement.
In the given example,it is the accuracy of percentage of scale range type as the measurements are to be made within a range where the sample has to be measured.
Accuracy in case of instruments is neglected up to ±0.5 percent.
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Describe the difference between physical and
chemical changes in terms of what happens to the matter involved in each
kind of change.
Answer:
Chemical changes cannot be reversed, their molecules are bonded together. Most Physical changes can be reversed, and their molecules are not bonded
Explanation:
balance this eqaution:
Answer:
H₂ + CuO → Cu + H₂O
Explanation:
We want to balance the given equation;
H₂ + CuO → Cu(OH)₂ + H₂O
To balance this we have to make sure the number of each element on the left is equal to the number of each element on the right.
Thus, the correct balanced equation is;
H₂ + CuO → Cu + H₂O
C₂H60
Which is the correct empirical formula
1. A spiderweb and a Kevlar jacket have some obvious differences. Which property is similar between the web and the jacket?
- surface area
- thickness, expressed as a number of atoms
- overall strength
- arrangement of atoms in molecules
2. Assuming silk from spiderwebs could be made just as strong as Kevlar, why would a company still choose to use Kevlar in producing bulletproof fabrics?
- A much larger amount of silk might be needed to produce the same effect.
- Spiderweb silk would likely be rejected by the body.
- The cost might be higher for producing spiderweb silk.
- Spiderweb silk likely involves more chemicals.
3. Which microscopic detail affects the strength of different forms of silk?
- Different silk strands are made with different types of atoms.
- Different types of silk are in long strands or in other very different arrangements.
- Different silk strands have different combinations of amino acids.
- Different types of silk do not have the same strength if they come from different sources.
4. Which type silk is the strongest?
- nonbiodegradable
- minor ampullate
- major ampullate
- biodegradable
5. Which natural source has been bioengineered to make silk proteins?
- mulberry leaves
- goat milk
- goat hair
- mulberry bark
help me. I will give brainliest.
There are different sources of fibres which can be genetically engineered for living organisms like the spider.
The fibre silk gotten from spiders are known to be the strongest, toughest materials on the Earth. But recently, engineers has designed amyloid silk hybrid proteins and produced them in engineered bacteria.
Even though these synthetically produced fibres are stronger than Kevlar, they prefer to use Kevlar because a much larger amount of silk might be needed to produce the same effect.
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Answer:
1.Arrangement of atoms in molecules
2.The cost might be higher for producing spiderweb silk
3.Different silk strands have different combinations of amino acids
4.Major ampullate
5.Goat milk
Some hypothetical alloy is composed of 12. 5 wt% of metal a and 87. 5 wt% of metal b. If the densities of metals a and b are 4. 27 and 6. 35 g/cm3, respectively, whereas their respective atomic weights are 61. 4 and 125. 7 g/mol, determine whether the crystal structure for this alloy is simple cubic, face-centered cubic, or body-centered cubic. Assume a unit cell edge length of 0. 395 nm.
Answer:
The number of
atoms in the unit cell is 2
Explanation:
