Answer:
A pure solid is heated and turns into a pure liquid.
Explanation:
No colour change recorded, only change of state, hence this is a physical change - physical changes I.e. change of state and temperature are not chemical reactions.
how many dots would a dot diagram for selenium, one of the group 16 elements, have?
Answer:
Because selenium is in the 16th column on the periodic chart, it has 6 valence electrons. Thus, the Lewis structure (or electron dot structure) for selenium has 6 dots around it.
It will look similar to this without the underscores:
__.
. Se:
_. .
Explanation:
The Lewis structure (or electron dot structure) for selenium has 6 dots around it.
What is an electron dot structure?Electron dot diagrams are diagrams in which the valence electrons of an atom are shown as dots distributed around the element's symbol.
Selenium is in the 16th column on the periodic chart, it has 6 valence electrons. Thus, the Lewis structure (or electron dot structure) for selenium has 6 dots around it.
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What causes metal atoms to form metallic bonds?
Answer:
Metallic bond, force that holds atoms together in a metallic substance. ... The atoms that the electrons leave behind become positive ions, and the interaction between such ions and valence electrons gives rise to the cohesive or binding force that holds the metallic crystal together.
Explanation:
Density = 7 g/mL
Volume = 10mL
∙What is the Mass?
Answer:
Mass is 70
Explanation:
Density= Mass divided by Volume
To find the mass you do the opposite of the equation- Volume times the density. Therefore, the mass is 70 because 10 times 7 is 70.
Hope this helps :)
Matching: Which is involved in making energy for the cell?
A. cell membrane
B. nucleus
C. endoplasmic reticulum
D. mitochondria
E. cell wall
F. ribosomes
A.
B.
C.
D.
E.
F.
Answer:
D. Mitochondria
Explanation:
This is the one that makes the energy that powers the cell, aka, the powerhouse.
Which observations is the best evidence that unknown liquid X is a composed of only pure substance
Answer:
A substance that is composed only of atoms having the same atomic number is ... 36 grams of an unknown liquid at its boiling point,.
I need help please #4
Answer:
The first one??
Explanation:
Could a person at the South Pole see the North Star? Explain.
Answer:
Yes
Explanation:
Because yes
Answer:
Yes, North is a direction and the south pole is a place so yes you can see the north star from the south pole
Explanation:
Which element could provide one atom to make an ionic bond with fluorine
How does an organism express a dominant trait?
Answer:
An organism will always express a dominant trait in the offspring if the dominant allele is present, even if there is only one copy
Explanation:
Hope this helps u:)
If in the reaction below 32 grams of C2H6 produces 44 grams of CO2, what is the % yield? 2C2H6 + 7O2 = 4CO2 + 6H2O
imagine the = is an arrow
Answer: 46.875%
the moles of C2H6 is 32/(12.2+6) = 16/15 (mol)
the moles of CO2 is 44/(12 + 16.2) = 1 (mol)
have:
2C2H6 + 7O2 ⇒ 4CO2 + 6H2O
0,5 <= 1
=> C2H6 reacts 0.5 mol
=> H = [tex]\frac{0.5}{\frac{16}{15} }.100=46.875[/tex]%
Explanation:
What is depicted as the yellow arrows in the following image? (Using a scientific vocabulary word we learned in class and provide its definition) Which makes a bigger current- faster moving electrons or slower moving electrons?
Answer:
Electric Current
Explanation:
The yellow arrows in the following image depict electric current. Electric current is defined as the continuous flow of electrons in an electric circuit. Electrons present in the conducting material which move from one to another atom randomly from the negative terminal through the connecting wires and back to the positive terminal.
Faster moving electrons make a bigger current because faster moving electrons collide more with each other that generates more heat which results into a higher current.
Hence, The yellow arrows in the following image depict electric current and Faster moving electrons make a bigger current.
The yellow arrow in the diagram shows the flow of electrons.
Current is defined as the flow of electrons in a circuit. The yellow arrows represents the direction of the flow of electrons in the circuit. The battery provides the potential difference that drives the flow of electrons through the wire.
Since current has to do with the movement of electrons in a circuit, the faster the movement of the electrons, the bigger the current.
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The identity of the element shown in the model above is determined by the number of -
Answer:
The number of protons or electrons in its atomic structure
Explanation:
Elements are substances which constitute the building block of matter. The smallest particles of elements that can ever exist are known as atoms. Atoms of different elements are different in their structure properties. This difference is due to to the number of sub-atomic particles present in the atom of each element.
The three sub-atomicparticles are protons, neutrons and electrons. Protons and neutrons are present in the nucleus of an atom, while the electrons revolve around the nucleus in orbits. The identity of each element is determined by the number of protons present in the atomic nucleus of that element. This is known as the atomic number of that element. For neutral atoms, the proton number is equal to electron number.
For the given element, the electron and proton number are respectively 4, therefore, the atomic number of the element is 4. The element with atomic number 4 is Beryllium.
Help me please do in 20 mins Do you think the pulse measurements you made are completely accurate? Why or why not?explain
Answer:
Gently place 2 fingers of your other hand on the left side of your chest. · Do not use your thumb because it has its own pulse that you may feel. · Count the beats for 30 seconds
Explanation:
Heart rate can be measured using electrocardiography, pulse ... Heart rate is generally expressed as the number of beats per minute (bpm). ... Because perfect accuracy is not always required in pulse-counting,
true or false: Some fungi are unicellular and some fungi are multicellular
Answer:
True
Explanation:
Which of these statements is TRUE about a nonrenewable energy resource? A. Its supply will never run out. B. It is used up faster than it is made. C. It cannot be burned as fuel. D. It can be replaced faster than it is used.
A population of snails lives in a large field. As the size of the population grows, individual organisms on one side of the field stop mating with individuals from the opposite side. Which of the following statements is true?
Over time, genetic differences between individual snails will increase.
Over time, genetic differences between individual snails will decrease.
The snail population will eventually split in two and evolve side by side in cospeciation.
This is an example of an increase in gene flow.
Answer:
I believe that the answer is c
Explanation:
The snails will split hope this helps! <3
Answer:
A. Over time, genetic differences between individual snails will increase.
Explanation:
A Lewis structure is a two-dimensional representation of a molecule that does not necessarily show what shape that molecule would take in three dimensions. From the given Lewis structure and what you know about VSEPR theory, identify the shape of the molecule. A molecule with atom Y single bonded with 2 X substituents. The Y atom has two lone pairs.
Answer:
Orbital geometry is Tetrahedral
Molecular geometry is Bent/V shape
Explanation:
Using the VSEPR theory which states that
The shape of a molecule depends upon the number of valence shell electron pairs (bonded or nonbonded) around the central atom. Pairs of electrons in the valence shell repel one another since their electron clouds are negatively charged. These pairs of electrons tend to occupy such positions in space that minimize repulsion and thus maximize distance between them. The valence shell is taken as a sphere with the electron pairs localizing on the spherical surface at maximum distance from one another. A multiple bond is treated as if it is a single electron pair and the two or three electron pairs of a multiple bond are treated as a single super pair. Where two or more resonance structures can represent a molecule, the VSEPR model is applicable to any such structureso we have Y as the central atom and it has 2X substituents on its either sides with two lone pairs on Y. This is a case of Y which has
2 bonds with X on either sides
2 lone pairs on Y
The orbital geometry will be Tetrahedral but its Molecular geometry will be Bent/V shaped
The formula of the compound will be YX2
Water with chemical Formula of H2O bears the same features.
The shape of the given molecule according to the VSEPR theory has been Bent/V shape.
VSEPR theory has been the Valence Shell Electron Pair Repulsion theory. It helps in the determination of the molecular and geometrical shape based on the presence of the atoms attached.
The given molecule has the presence of 2 single-bonded X atoms.
The atoms repel each other, while the presence of loan pairs results in the force for the molecule to occupy the tetrahedral orbital geometry. The repulsion from the loan pair to the X atoms acquires the Bent V shape as molecular geometry.
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I would really appreciated if someone can help !!
A student calculated that 15 grams of his product were supposed to be produced. After completing the experiment, he actually
collected 11 grams of product. What is his percent yield?
a 73%
b 7.3%
c 14%
d 140%
which of these is a characteristic
of index fossils
Answer: A index fossil is any animal or plant preserved in the rock record of the earth that is characteristic of a particular span of geologic time or environment. A useful index fossil must be distinctive or easily recognizable, abundant, and have a wide geographic distribution and a short range through time.
Explanation:
Which element is depicted from this orbital diagram? A NA N 3p 35 Increasing Energy A NA A 2p 2s 11 1s O Fluorine O Chlorine O Neon Argon
Answer:
Explanation:
neon
The elements on the Periodic Table of the Elements are arranged in order of increasing
Answer: The Atomic Number increases. Hope this helps!!!
Explanation:
Elements are arranged from left to right and top to bottom in order of increasing atomic number. Order generally coincides with increasing atomic mass.
Answer:
The Atomic number increases....
Explanation:
Duh
Homeostasis is
A.) a way to describe an organism's name
B.) the ability to maintain stable internal conditions
C.) the way an organism moves
O Other:
You have a shiny metal disc that weighs 1.31 kg that you want to find out what its made of. When you put the disc into a graduated cylinder with 5L in it, you see that the water level rose by about 125 mL. You have a list of densities for various shiny metals: silver= 10.5 g/ mL, nickel= 8.9 g/mL, titanium = 4.5 g/mL, and rhodium = 10.7 g/ mL. What is the disc made of?
Answer:
The disc is made of silver.
Explanation:
To solve this question we need to calculate the metal's density. To do so we need its mass (already given by the problem, 1.31 kg) and its volume.
Following Archimedes' principle, the volume of water displaced by the disk is equal to the disk's volume. This means the metal's volume is 125 mL.
Now we convert 1.31 kg into g, to better compare with the given options:
1.31 kg * 1000 = 1310 gFinally we calculate the metal's density:
Density = Mass / VolumeDensity = 1310 g / 125 mL = 10.48 g/mLLooking at the densities given by the problem, the closest one is silver.
Which of the following is a property of metals?
1. Olow melting point
2. O good electrical conductor
3. O good thermal insulator
4. O cannot bend without breaking
Criminalist Julie Sandel is investigating a series of threatening notes written in pencil and sent to a local politician. A suspect is arrested and Julie directs the suspect to prepare writing samples to compare to the writing on the notes. She has the suspect sit at a desk in an empty office and gives him a pen and a piece of paper. She begins to read one of the notes and asks the suspect to write the words she dictates. After reading about half a page, she stops, then dictates the same part of the note a second time for the suspect. At one point, the suspect indicates that he does not know how to spell one of the words, so Julie spells it for him. After completing the task, Julie takes the origi- nal notes and the dictated writing from the suspect to a document examiner. What mistakes, if any, did Julie make?
Answer:
See explanation
Explanation:
Julie Sandel, the Criminalist made several mistakes in handling this investigation. They include;
It is true that handwriting can be deduced by comparing a suspects's handwriting to the questioned document, however Julie made a mistake by not making the suspect to write many pages. The suspect may intentionally decide to change his/her hand writing. This trick can be neutralized by asking the suspect to write several pages.
Secondly, the suspect ought to have been given a pencil and paper similar to the one used to write the threatening document. Rather, Julie gave the suspect a pen.
Thirdly, the suspect only wrote half a page instead of a full page. Secondly, Julie took only two exemplars when she should have taken more.
She should not have dictated the spelling of any word to the suspect. The examiner is not supposed to do that.
The threatening documents should have first been shown to the document examiner before taking the exemplars.
The process of making proteins is called protein
Answer:
protein sysnthesis
Explanation:
Which of the following does NOT agree with the Law of Conservation of Mass?
A. Mass can be destroyed.
B. Matter cannot be created.
C. Mass prior to chemical change is the same as mass after chemical change.
mass prior to chemival change is. thesame as mass after chemical change
1. 2KCIO3, -- 2KCI + 302
How many moles of O2 will be produced from 2.25 moles of KCIO3?
Answer:
3.375moles of O₂
Explanation:
The reaction expression is given as;
2KClO₃ → 2KCl + 3O₂
Number of moles of KClO₃ = 2.25moles
Now;
To find the number of moles of O₂ produced we use known number of moles.
So;
2 mole of KClO₃ will produce 3 moles of O₂
2.25moles of KClO₃ will produce [tex]\frac{2.25 x 3}{2}[/tex] = 3.375moles of O₂
Yes its flocab but...HELPPPPPP(science)
Answer:
dense
Explanation:
Answer: dense
Explanation:
what is formula for Bromine?
Br2
I looked it up and it said that Bromine's formula is Br2
Answer:Br2
Explanation: