Answer:
I believe the answer to your question would be A. this is because it is controlled with a good habitat and also has good variants that are needed in a good plants growth.
Explanation:
EASY 30 POINTS! PLS HELP ME T-T
1. True or false? All atoms in an element contain an identical number of neutrons.
2. An atom with a _______ charge has the same number of protons and electrons.
3. An atom that has a different number of electrons and protons is called a(n) _______.
Answer:
1.false
2.neutron
3.neutron
Answer:
1. false
2. zero
3. isotopes
hope it helps
Revision has a atoMic number of 37 and a mass number of 85. HIW many protons, neutrons and electrons does an ion of rubidium with a 1+ charge have
Answer: 37 protons, 48 neutrons, and 36 electrons.
Explanation: I assume "Revision" is Rubidium. It is atomic number 37, so it has 37 protons. It's atomic mass is 85, so it has an average of (85-37) = 48 neutrons. It has a charge of +1, so one electron of the original 37 has left.
state two application of chemistry on each of the following:-
1.forensic
2.agriculture
3.industrial
4.millitary
5.space science
write the chemical formula for the following compound -magnesium chloride, zinc sulphide Sodium,sodium sulphate, calcium bicarbonate.
Answer:
magnesium chloride: MgCl2
zinc sulphide: ZnS
sodium sulphate: Na2SO4
calcium bicarbonate: Ca(HCO3)2
Which of these are PHYSICAL changes?
А.
cutting, tearing, freezing, thawing, folding.
mixing without chemical changes
B.
burning, rusting, forming a new substance from
two different substances, exploding, cooking
Answer:
the answer to this problem is a
Round the following number to 3 significant figures:
.003053456
.00310
.003
.00305
0.003053
Answer:
See explanation below for answers
Explanation:
0.00305
0.00310
0.00300
0.00305
0.00305
When there is a decimal point, you must skip the zeros until you reach a number. Once you reach that number, you move 2 more places to the right of that number in order to have 3 significant figures. Hope this helps!
What is the mass of six of these marbles? What is the volume? What is the
density?
Answer:
All right. So let's calculate the density of a glass marble. Remember that the formula for density is mass over volume. So if I know that the masses 18.5 g. And I know that the um volume is 6.45 cubic centimeters. I can go ahead and answer this to three significant figures. So it's going to be 2.87 grams per cubic centimeter. Okay, that's our density. Now, density is an intensive process. Okay. We're an intensive property. I really should say. It doesn't depend on how much you have. Mhm. If I have one marble, its density is going to be 2.87 g per cubic centimeter. If I have two marbles, the density will be the same because I'll double the mass and I'll also double the volume. So when I divide them I'll get the same number. Okay, that's what makes it an intensive property. No matter how many marbles I have, they'll have the same density. Mass though is not an intensive property. So if I have six marbles and I want to know what the massive six marbles is. Well, I know the mass of each marble is 18.5 g. So the mass of six marbles Is going to be 100 11 g. Because mass is an extensive property. It depends on how much you have. If I change the number of marbles, I'm going to change the mass. That's an extensive property. All right. So we've calculated the density. We've calculated the mass and then what happens to the density of one marble compared to six marbles as we mentioned before. Since densities and intensive property, the densities will be the same, no matter how may.
Explanation:
the nucleus of an atom is positively charged why
Answer:
hello ~~
look nucleus is mixture of neutrons and protons.. right?
and we know neutrons have no charge and protons are positively charged so overall charge of nucleus is positive
sound travels at 331m/s. How long would it take for sound to travel across lake tahoe, which is 21.6 miles long
Answer:
It would take sound 104.998 seconds to travel across lake tahoe.
Explanation:
First let's convert the miles to meters, so, 21.6 miles = 34754.4 meters
Now, we will divide this number in meters by 331. So, 34754.4 / 331 = 104.998
And what will the unit be? Seconds will be the unit for time here so 104.998 seconds.
SURELY SOMEONE HELP it’s urgent plllss I’ll brainlist u/5 star!!! answer the ones u know. :)
Answer:
3 exothermic reaction. only that much
Hi,
These are the answers.
• Question 2. C , Substance dissolves
• Question 3. D , Exothermic reaction
• Question 4. C , Endothermic reaction takes place
• Question 5. A , the products formed has more energy than reactants
Hope it helps you... pls mark brainliest if it helped you
Multiple Choice Questions 1. Which of the following statement best describes an atom? A. Protons and electrons are grouped together in a random pattern. B. Protons and electrons are grouped together in an alternating pattern C. A core of protons and neutrons surrounded by electrons. D. A core of electrons and neutrons surrounded by protons. 2. Table 5.10 shows the atomic mass of four stable isotopes of an element X. 119
Answer:
C is Correct
Explanation:
Protons and Neutrons make up the Nucleus while Electrons surround the nucleus in circular orbits with continuous rotation.
Express 0.021 in scientific
notation.
[ ? ]10
Answer:
0.021 in scientific notation is 2.1 x 10^-2
Explanation:
Since there are two zeros before the non-zero digits, 10 should be raised to -2.
hope this helps
Using scientific notation, one can express extremely big or extremely small values. When a number between 1 and 10 is multiplied by a power of 10, the result is represented in scientific notation. 0.021 in scientific notation is 2.1 x 10⁻².
A way to express numbers that are either too large or too little to be conveniently stated in decimal form is through scientific notation. It is also known as "scientific form" in Britain, because scientists, mathematicians, and engineers frequently use it for intricate calculations involving large numbers.
A condensed manner of writing numbers is known as scientific notation (also known as standard form). A number is represented by a number from 1 to less than 10, multiplied by a power of 10, when it is written in scientific notation.
To know more about scientific notation, visit;
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What can we say about
protons?
A. They are in the nucleus and never
leave.
B. They move around outside the nucleus.
C. They move in and out of the nucleus.
Answer:
A. They are in the nucleus and never leave.
Explanation:
Protons as well as neutrons are located in the nucleus of the atom.
hope this helps!
The periodic table below shows major regions in different colors. Which answer choice describes the noble gases?
A. All of the elements of Period 1 in orange boxes
B. The two separate rows of elements in dark and light blue boxes at the bottom
C. All of the elements in green boxes
D. All of the elements of Group 18 in orange boxes
Answer:
D. all of the elements of Group 18 in orange boxes
i need help please........
Answer:
cd
Explanation:
image is formed due to reflected light rays and it is enlarged because image distance/ object distance = height of image/height of object
v>u so image is enlarged
what is force ?write its effects.
Answer:A force is a push or pull upon an object resulting from the object's interaction with another object.
A force acting on an object causes the object to change its shape or size, to start moving, to stop moving, to accelerate or decelerate
Calculate the no. of moles in 25gm of calcium phosphate
PLz Fast
answer/
1 grams Calcium Phosphate to mol = 0.00322 mol
no. of moles= 0.00322×25
no. of moles = 0.0805
Nhiệt phân hoàn toàn 1,88g Cu(NO3)2.Khí bay ra cho hấp thụ vào H2O tạo thành 2 l dd A. Dd A có pH= ?
Answer: theo mình thì mình làm như sau
cu(no3)2 nhiệt phân hết
\Rightarrow nNO2= 0,02mol
nO2=0,005mol
khi hấp thụ O2 và NO2 vào nước ta có
2NO2 + 1/2 O2\Rightarrow 2HNO3
phản ứng là vừa đủ nên
nHNo3= 0,02 mol
pH HNO3=2
khi cho 0,001mol NaOH vào thì phản ứng trung hòa
H+ + OH- \Rightarrow H20
nHNO3=0,02/20=0,001
nhận thấy nH+ =nOH- nên phản ứng vừa đủ
pH của dd Y=7
theo mình giải là như vậy
Explanation:
Nate and Vic are trying to determine the atomic mass of the atom shown below. Nate thinks it has an atomic mass of 11 u, while Vic thinks it has an atomic mass of 6 u. Who is correct and why?
A. Nate is correct. An isotope’s atomic mass is based on the number of protons and neutrons in the nucleus.
B. Vic is correct. An isotope’s atomic mass is based on the number of electrons in the electron cloud.
C. Vic is correct. An isotope’s atomic mass is based on the number of protons in the nucleus.
D. Neither is correct. The atomic mass is based on the number of neutrons in the nucleus. This isotope’s atomic mass is 5 u.
Answer: A is correct. I don't see the "element shown below," but it isn't needed to answer this question.
Explanation: By definition, the atomic mass is based on the sum of protons (1 AMU each) and neutrons (1 AMU each). Electrons are assigned a value of 0 AMU.
Compare and contrast the three types of mixtures (solutions, colloids, and suspensions).
Answer:
solutions is a homogenous mixture while colloids and suspensions are heterogeneous mixtures made up of 3 or more substances
Explanation:
homogeneous- made up of one thing
heterogeneous- made up of 2 or more things
what is the concentration of hydrogen ion, H+, present in a water sample if 100. ml of the sample requires 7.2 ml of 2.5 x 10 -3 M NaOH to be neutralized
Answer: 1.8x10^-4 M H+
Explanation: The number of moles of NaOH added to the 100 ml soultion will be equal to the number of moles of H+ present in that solution.
Moles NaOH in 7.2 ml of 2.5x10^-3 M NaOH
(2.5x10^-3 M NaOH) is the same as 2.5x10^-3 moles NaOH/liter
(2.5x10^-3 moles NaOH/liter)*(7.2 ml)*(1 liter/1000ml) = 1.8x10^-4 moles NaOH used to titrate 100 ml of the acid. That means there was 1.8x10^-4 moles of H^+ in 100 ml.
Concentration of H^+ = (1.8x10^-4 moles H)/0.100 l) = 1.8x10^-4 M H+
(pH of 3.74)
PLZ HELP MEEE
A tire company wants to determine what kind of rubber will last the longest for their tires. What are some variables that the researchers will want to make controlled variables?
In an experiment, we can define 3 types of variables.
Independent variables: Are these ones that the scientist can control and modify, in this case, would be the kind of rubber for the tires.
Dependent variables: Are the variables that react to the changes in the independent variables. In this case, would be "how much lasts each type of rubber".
Controlled variables: Are all of these variables that also have an impact on the dependent variable, so we need to control them (fix them) so they do not affect the study of the independent variable.
So, for this particular experiment, to find controlled variables we need to think on what things do affect the durability of tires.
Some examples can be:
The material of the ground where the tires are being tested.The temperature of the ground where the tires are being tested.The type of car where the tires are being tested.The speed at which the tires are being tested.The internal pressure at which the tires are being tested.If you want to learn more, you can read:
https://brainly.com/question/17687509
underline and identify the parts of the text on this page that use examples of how the flow of the matter through a system is driven by energy and can do the work.
The parts of the text on the page that use examples of how the flow of matter through a system is energy driven and has the capacity to do work are;
1) The flow of water down rivers passing through hydro power dams to perform the following works;
River bank particle erosionElectric power generation2) The flow of electrons that corresponds to the flow of electricity (in the reverse direction) to perform the following works;
Light bulbs turn onTelevisions are powered3) The lifting of the hammer by the cam which gains gravitational potential energy that is converted to kinetic energy as the hammer drops
The hammer is repeatedly lifted and dropped by the cam to do the following work
Hammering a metal piece into shape4) The chemical potential energy stored in bonds by virtue of the relative atomic distances which produces kinetic energy from the chemical potential energy
Lear more about energy conversion here:
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chất có ở đâu ? nước tự nhiên là chất hay hỗn hợp
Answer:
Water, H2O, is a pure substance, a compound made of hydrogen and oxygen. Although water is the most abundant substance on earth, it is rarely found naturally in its pure form. Most of the time, pure water has to be created. Pure water is called distilled water or deionized water.
What causes the pressure inside oxygen tanks to change as they are filled?
A. The volume of the container changes.
B. The temperature of the gas changes.
C. The number of gas molecules changes.
D. The pressure outside the tanks changes.
Answer:
the answer is the number of gas molecules changes.
What is the signifcence of H, 2H, 3 H, H2, 2 He, Na,
Snaco, ouco, CO, 460?
H=hydrogen,H2=hydrogen atoms,
What is the control in the experiment?
Answer:
C. the amount of drug x given to mice
All the following process produces hematite except
A roasting of siderite
B oxidation of iron
C oxidation of magnetite
D drying of limonite
E no correct answer
Answer:
D)driying of limonite these is the answer
Sorry for the spamming, but this question is URGENT here,
Which of the following is
property of metals?
A. brittle
B. good conductivity."
C. poor conductivity
(Btw here’s a picture :O)
Option B, Metals have good conductivity.
Hope it helps you.. pls mark brainliest if it helps you
In two atoms atom 'X' looses two electrons and atom 'Y' gains two electrons to form a compound 'XY'.Name the bond formed between X and Y.With two properties of the compound.
Please help me and i will mark you as brainleist.
Answer:
The bond formed between XY is "Ionic bond"
Explanation:
The bond is ionic bond because the compound XY is formed due to the gaining and loosing of electrons
Properties of Ionic compounds:
They form crystals
They are good insulators
They have high melting and boiling points
.
.
.
Hope it helps
