Answer:
发你如果热客人看看如果
Explanation:
Answer:
result = 310
significant figures = 2
Explanation:
How to round significant figures:
look the first non-zero digit if rounding to one significant figure, look the digit after the first non-zero digit if rounding to two significant figures. draw a vertical line after the place value digit that is required.look at the next digit.
result = 310
significant figures = 2
In a compound, chemical energy is _______________ when bonds break.
a
absorbed
b
released
c
both A and B
d
neither A or B
In the formation of an ionic compound a metal atom is most likely to __________ valence electrons
Answer:
To lose valence electrons.
Explanation:
Which one of the following is an example of extensive
property?
a Hardiness
be Density
a Meliting point
d. Electrical resistance
Clear my choice
Answer:c
Explanation:
Answer:
mass an volume or hardines be density
4. What is a common cause of acid rain?
Answer:
Exhaust from cars, trucks, and buses releases nitrogen oxides and sulfur dioxide into the air. These can cause acid rain.
Hope this helps! :)
What is considered a pure substance?
Answer:
A substance that has a fixed chemical composition throughout is called a pure substance such as water, air, and nitrogen. A pure substance does not have to be of a single element or compound.
Explanation:
Compound: A substance that contains more than one element
pure substance: is made up of one substance made up of only one type of molecule
Put the sets of 3 elements in order from least metallic character to most metallic character. Help please!!
Answer:
29:Mn,V,Sr
30:Ni,Pd,Cs
31:Cr, Mo, W
32:Sn,Pb,Ti
33:F, P, As
Sorry I was in a rush so it may not be right; so check with this picture to help you out.
plesse hurry aand help with QQQQQ
Answer: the answer should be A the first one
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A chemist measured the temperature of a liquid to be 26 ∘C, then she heated the liquid to 83 ∘C. By how many Kelvins did the temperature change.
Answer: 57.C
Explanation: simple subtraction
NEED HELP!PLEAE WITH CHEMISTRY!
3. both covalent and ionic
EXPLANATION
Sodium Phosphate is an ionic compound formed by two ions, Sodium Na+ and Phosphate PO−3 . In order for these two polyatomic ions to bond the charges must be equal and opposite. Therefore, it will take three +1 sodium ions to balance the one -3 phosphate ion. However, polyatomic ions are held together by covalent bonds, so this compound contains both ionic and covalent bonds.
Why is knowledge of the activity series crucial in choosing which metal to build things with?
Answer:
activity series is a list of substances ranked in order of relative reactivity.
For example, magnesium metal can displace hydrogen ions from solution. So magnesium is more reactive than hydrogen:
Mg(s) + 2H⁺(aq) → H₂(g) + Mg²⁺(aq)
Zinc metal can also displace hydrogen ions from solution:
Zn(s) + 2H⁺(aq) → H₂(g) + Zn²⁺(aq)
so zinc is also more active than hydrogen.
But magnesium metal can displace zinc ions from solution:
Mg(s) + Zn²⁺(aq) → Zn(s) + Mg²⁺(aq)
so magnesium is more active than zinc.
The activity series including these elements would be Mg > Zn > H.
Chemists have built up a complete activity series in a similar way.
The most active metals are at the top of the table; the least active are at the bottom.
Any metal that is higher in the series will displace a metal that is below it in a
The knowledge of the activity series in choosing which metal to build things with because; it provides a basis for determining which metal ion is able to displace the other upon chemical interaction.
The choice of building material is a very important design consideration.
This is so because careful consideration must be taken while deciding which metal to build things with as the reactivity of metals vary.This variation is carefully quantified by the position of metals on the activity series.
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Copernicus believed the planetary motions were due to:
Answer:circular heliocentric orbits.
Explanation:
I need help with the question below
Answer:
D po
Explanation:
Sana nakatutulong
#Carry on learning
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Element X is in group 2, and element Y is in group 7, of the periodic table. which ions will be present in the compound formed when X and Y react together?
A) X^+ and Y^-
B)X^2+ and Y^-
C)X^+ and Y^2-
D)X^2- and Y^+
Answer:
Element X has valency 2 while Y Valency 2, element Y has high tendency of gaining electrons for its stability thus the compound formed will be B
elements X is positively charged while Y will be negatively charged
The groups or the families in the periodic table are denoted by the vertical column. Element in group 2 and 7 forms compound with ions X²⁺ and Y⁻. Thus, option B is correct.
What is the periodic group?A group of the periodic table is also called a family that has the elements placed togther with the same number of the valence electron. Group II has two valence electrons and VII has seven valence electrons in the outer shells.
The two valence electrons of the atom can be donated easily compared to acquiring the six electrons to complete the octet and stability. Similarly, the seven valence electrons are hard to donate but can accept one electron to achieve satbility.
The group II element X will donate its two electrons to acquire a +2 charge, whereas group VII element Y will accept one electron and acquire a -1 charge.
Therefore, option B. X²⁺ and Y⁻ presents the ions of the compound.
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Can someone give me Two methods for monitoring and minimizing a human impact on the environment?
ain the energy transformation that occurs when a hair dryer is plugged in and turned on.
Group of answer choices
Chemical energy transforms into electrical and sound energy.
Electrical energy transforms into mechanical and thermal energy.
Mechanical energy transforms into chemical and electrical energy.
Thermal energy transforms into electrical and gravitational energy.
Answer:
Mechanical
Explanation:
Since, this mechanical energy gets converted into thermal energy due to which hairs get dry. Thus, we can conclude that the energy transformation that occurs when a hair dryer is plugged in and turned on is that electrical energy transforms into mechanical and thermal energy.
5 example of similarities between compression and tension stress?
Answer:
Mark me as Brainliest please
Explanation:
Compression vs Tension
Tension and compression are two concepts discussed in physics. Tension is a force, while compression is a phenomenon. Both these concepts play important parts in fields such as mechanical systems, automobile engineering, heat engines, material science, pendulums and various other fields. It is vital to have a proper understanding in tension and compression in order to excel in such fields. In this article, we are going to discuss what compression and tension are, their definitions, applications of compression and tension, the similarities between compression and tension and finally, the difference between compression and tension.
A student compares a sample of isooctane with some petrol. the student found that the isooctane boiled at 99°C while the petrol boiled between 45 and 95°C. which of these is a puse Substance? Explain ur answer.
Answer:
The isooctane
Explanation:
A pure substance is, according to Wikipedia, "a chemical substance is a form of matter having constant chemical composition and characteristic properties." That's a lot of words, but we just need to focus on some of them: "constant... characteristic properties." The properties of a pure substance always stay the same, no matter what.
The boiling point of a substance is one of its properties. It looks like the petrol boils at different points, between 45 and 95°C. The isooctane, on the other hand, boils consistently at 99°C. So, we can infer that the isooctane is the pure substance.
Hopefully that was helpful! If you need more questions answered, let me know. :)
You have been given four substances that are all white
solids at room temperature. List three specific tests that
you could perform to figure out whether they are ionic or
molecular compounds.
Ionic compounds have a high melting point while molecular compounds have a low melting point.
If I have a white solid, this solid may be ionic or molecular. Ionic substances dissolve in water while molecular substances do not dissolve in water. This is the first test.
Secondly, an ionic solid has a high melting point while a molecular solid has a low melting point. Again, ionic substances are crystalline when felt while molecular compounds are non crystalline when felt.
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PLEASEEE ANSWER PLEASEEE PLEASE I’ll mark brainliest
Answer:
Lithium has 1 valence electron, Sulfur has 6
A is oxidized, B is reduced
A is reducing agent, B is oxidizing agent
Explanation:
when an atom loses electrons, it is oxidized
when an atom gains electrons, it is reduced (almost think of when you add a negative number to a positive number, the positive number gets smaller or is reduced)
determine whether each phrase describes starch, glycogen, or cellulose.
Answer:
Starch is a soft, white, tasteless powder that is insoluble in cold water, alcohol, or other solvents.
glycogen is a substance deposited in bodily tissues as a store of carbohydrates. It is a polysaccharide which forms glucose on hydrolysis.
Cellulose is a molecule, consisting of hundreds and sometimes even thousands of carbon, hydrogen and oxygen atoms.
Heavy rains fill a reservoir, causing the dam that holds the water to break. As a result, the areas downstream are suddenly flooded. Which question would a
scientist seek to answer?
A. What will be the long-term effect of the flood on the plants and
animals in the area?
B. Who was responsible for the design flaw in the dam?
C. What changes in regulations are needed to prevent future dam
failures?
D. How much money should be spent to ensure dam safety?
need help w this question
Answer:
ok you got it you just need to add.
Explanation:
add 5 times and she what you get.
Which of the following is the equation for wave speed?
Answer:
[tex]{ \boxed{ \mathfrak{ \: answer : \: { \bf{v = f \lambda}} }}}[/tex]
v is the wave speedf is frequencylambda is wave lengthA sturdy plant is placed in an airtight, transparent container. The entire experiment is then weighed. For 10 days, the plant grows inside the container. After 10 days, the container is weighed again. The air inside the container is pumped out and carefully analyzed.
What is true about the air inside the container and the mass of the experiment?
-The air is richer in carbon dioxide. The mass of the experiment has not changed
-The air is richer in oxygen. The mass of the experiment has changed.
-The air is richer in carbon dioxide. The mass of the experiment has changed.
-The air is richer in oxygen. The mass of the experiment has not changed.
Answer:
hi
Explanation:
bye
What do all the molecules in the table have in common?
Answer:
They all consist of the same amount of protons, electrons, and neutrons in an element.
Explanation:
For example in water (H20) contains 1 atom of protons, 1 atom of electrons and 1 atom of neutrons.
Hand warmers and instant cold packs use _____ that release or absorb thermal energy.
Answer:
Hand warmers and instant cold packs use Endothermic that release or absorb thermal energy.Hand warmers and instant cold packs use endothermic reaction that release or absorb thermal energy.
What is thermal energy?Thermal energy is defined as by virtue of its temperature, a system in a condition of thermodynamic equilibrium contains internal energy. Fossil fuels like natural gas, coal, and oil are examples of thermal energy sources. They also include solar heat, electric heat pumps, and geothermal heat. Thermal energy is a type of kinetic energy, which is energy brought on by motion, and is brought on by the motion of particles. Things have an interior temperature as a result of thermal energy, which can be detected with a thermometer.
Endothermic reaction is defined as the chemical processes that result in the formation of products when the reactants absorb heat energy from their surroundings. A chemical reaction or physical change is referred to as being endothermic when heat is absorbed by the system from the environment. An endothermic process causes the system to absorb heat from its surroundings, which causes the surroundings' temperature to drop.
Thus, hand warmers and instant cold packs use endothermic reaction that release or absorb thermal energy.
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An atom's Lewis dot structure has three dots. Which of the following elements could it be, and why? (4 points)
Group of answer choices
Aluminum, because it is in group 13 and has three valence electrons.
Lithium, because it is a group 1 element with three total electrons.
Magnesium, because it is in period 3 and has three valence electrons.
Potassium, because it is an alkali metal and has three inner shell electrons.
Answer : The correct option is, Magnesium because it is a group 2 element with two valence electrons.
Explanation :
Element = Calcium
Atomic number = 20
Electronic configuration of Ca =
Number of valence electrons in Ca = 2
The number of inner shell electrons in Ca = 18
This option is wrong because lewis-dot structure shows only valence electrons not inner shell electrons.
Element = Carbon
Atomic number = 6
Electronic configuration of C =
Number of valence electrons in C = 4
This option is wrong because only outermost p-sublevel electrons are not showing in lewis-dot structure.
Element = Lithium
Atomic number = 3
Electronic configuration of Li =
Number of valence electrons in Li = 1
This option is wrong because it has only 1 electron in outermost shell.
Element = Magnesium
Atomic number = 12
Electronic configuration of Ma =
Number of valence electrons in Ma = 3
This option is correct.
Lewis-dot structure : It is defined as the structure in which valence electrons of the atom is shown as dots.
ANOTHER EXPLANATION:
Answer: C. Magnesium, because it is a group 2 element with two valence electrons.
An atom's Lewis dot structure has two dots. Which of the following elements could it be, and why?
A. Calcium, because it is an alkaline earth metal with two inner shell electrons.
B. Carbon, because it has two electrons in its outermost p sublevel.
C. Lithium, because it is a group 1 element with two bonding electrons.
D. Magnesium, because it is a group 2 element with two valence electrons.
Explanation:
If you were to look at the periodic table magnesium would be in group 2. Since magnesium is in group 2 therefore it will have two valence electrons. Calcium is another possible answer because it is also in group two, but for this quiz it is incorrect. Lithium is incorrect because it is in group 1 and therefore it would only have 1 valence electron. Carbon is also incorrect because it is in group 14 so it would have 4 valence electrons. Hope this helps and makes sense.
Good Luck!!
Have a great day Studying!
The Lewis dot structure of an atom has three dots. With three valence electrons and belonging to group 13, which of the following elements may it be?
Are the elements of group 13 metals?The semi-metal boron (B) and the metals aluminum (Al), gallium (Ga), indium (In), and thallium (In) are all members of the boron family (Tl). The periodic table's fifth element, boron (Z=5), is found in Group 13. It is categorized as a metalloid because of its characteristics, which combine those of metals and nonmetals.
What traits does group 13 exhibit?The Periodic Table of Elements places these elements in Group 13 (XIII) of the p block. Metallic elements include thallium, gallium, indium, and aluminum. In their outermost shells, they each have three electrons shell with the valence electron configuration ns2np1 (one electron in the p orbital and a complete s orbital).
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.
24.) In humans animals and plants the DNA is found in the?
Answer:
chromosome
Explanation:
Answer:
Most of the DNA in all animals, humans, and plants is found in the cell nucleus. Humans, animals and plants contains both DNA and RNA in the cell nucleus and they have to be present in all because every organisms structure and function directly depends upon them.
Explanation:
Copper 11 oxide and charcoal are black solids . How would you distinguish between the two solids
What’s solubility need it for science
Answer:
the ability of a compound to dissolve
Explanation:
salt dissolves in water so it would be soluble.
oil does not dissolve in water so it is not soluble
