Answer:
Tell your instructor immediately
11. Calculate the number of atoms of sodium in a 4.5-gram sample.
A 1.2 x 1023 atoms Na
B 2.5 x 1023 atoms Na
C 1.7 x 10-22 atoms Na
D 3.1 x 1024 atoms Na
Answer:
A
Explanation:
A(n) __________________ is a statement of what you think will happen during an investigation. It is often written in the form of an if... Then... Because statement. Group of answer choices
Answer:
Hypothesis. Hope this helped! :)
YOU DO:
1) A 15.0 gram sample of sodium hydrogen carbonate, NaHCO3, was contaminated with an impurity. In order
to determine the purity of the sample, it was heated to decompose the material according to the following
reaction:
2NaHCO3 → Na2CO3 + H2O + CO2
If 6.35 grams of sodium carbonate, Na2CO3, were recovered, what percentage (by mass) of the sample was
sodium hydrogen carbonate, NaHCO3?
I
Answer:
67.1%
Explanation:
Based on the chemical equation, if we determine the moles of sodium carbonate, we can find the moles of NaHCO₃ that reacted and its mass, thus:
Moles Na₂CO₃ - 105.99g/mol-:
6.35g * (1mol / 105.99g) = 0.0599 moles of Na₂CO₃ are produced.
As 1 mole of sodium carbonate is produced when 2 moles of NaHCO₃ reacted, moles of NaHCO₃ that reacted are:
0.0599 moles of Na₂CO₃ * (2 moles NaHCO₃ / 1 mole Na₂CO₃) = 0.1198 moles of NaHCO₃
And the mass of NaHCO₃ in the sample (Molar mass: 84g/mol):
0.1198 moles of NaHCO₃ * (84g / mol) = 10.06g of NaHCO₃ were in the original sample.
And percent of NaHCO₃ in the sample is:
10.06g NaHCO₃ / 15g Sample * 100 =
67.1%Which type of forest consists of cone-
bearing evergreen trees that often
grow very tall, but provide little
canopy?
A. Coniferous Forest
B. Deciduous Forest
C. Tropical Rainforest
D. Grassland
Answer: A, Coniferous Forest.
Do you think the density of the rock models affects the melting rate? Why or why not? I said no, but I need help on the part that says why or why not. Please use your own knowledge. Looking it up won't help. I have tried. :)
Answer:
1) Yes the density does affect it's melting rate.
Explanation:
Simply because the more rock the more time. For instance an ice cube that is empty inside ( has less density ) will take less to melt. Verses an ice cube that is ice to its inner core ( has more density ) will take more time to melt in the same temperature as the first ice cube.
Atoms of hydrogen can become helium atoms during a chemical reaction.
True
False
Answer:
false
in chemical reaction element doesnot change into another
Explanation:
An unknown solid has a mass of 837.21 g. The volume of the solid, determined by water displacement is 37.00 mL. Calculate the density of the solid.
Answer:
The answer is
22.63 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]
From the question
mass = 837.21 g
volume = 37.00 mL
The density of the substance is
[tex]Density = \frac{837.21}{37} \\ = 22.62729[/tex]
We have the final answer as
22.63 g/mLHope this helps you
What is the density of a purple gas that has a mass of 10 g and a volume of 20 mL? Show your work!
Answer: 0.5g/ml
Explanation:
The density of a substance is given by the following formular; Mass / Volume,
Where mass = 10g
volume = 20ml
Density = 10g/ 20ml = 0.5g/ml
Did dalton’s atom have any protons, neutrons, and electrons?
Answer:
no
Explanation:
No, dalton’s atom haven't any protons, neutrons, and electrons because they were not discovered until later.
Answer:
No
Explanation:
no, because according to him an atom is a tiny indestructible sphere with mass on it. In his theory, Dolton did not know about Protons, neutrons and electrons.
4. What is the proper way to prepare an acid solution?
Answer:
Always add acid to a large volume of water. The solution may then be diluted with additional water to make one liter. You'll get an incorrect concentration if you add 1 liter of water to the acid.
An acid is concentrated solution hence, it should be added to considerable quantity of water. The required volume can then be adjusted by adding more water.
What are the properties of an acid?Acids form aqueous solution and have the property of electric conductivity. Acids reacts with other molecules by forming a covalent bond.
Acids are corrosive in nature, sticky to touch, tastes sour and have strong smell.
Acids can be qualitatively detected through litmus test. They turn blue litmus paper red. Their pH is < 7 on pH scale.
Acids can be classified as:
Strong acids - are the acids that dissociate in water completely.Weak acids - are the acids that partially dissociate in water.Chemically, acids can react with other metals, carbonates and bases. Common examples of acids are vinegar (acetic acid), hydrochloric acid (HCl), sulfuric acid (H2SO4) etc.
Acids are found in food items such as citrus fruits. Acetic acid is widely used in certain food preparations and as food preservative. Acids are commercially used in dyes, paints and in soft drinks.
Thus, acids are important in many chemical reactions.
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Q1.What is the mass of 5 moles Of 1.Mg 2.CaCO3 Q2. Calculate the number of atoms in 10g of Na Q3.calculate the number of molecules in 10g of NaCl Q.4.What is Avogadro's number? How many number of atoms are present in 4g of Oxygen?
Answer:
Explanation:
Q1) as we know that moles=given mass/molar mass
mass of 5 moles of Mg is
mass =moles*molar mass
mass=5*24
mass=120 g
mass of 5 moles of CaCO3 is
mass= moles*molar mass
mass=5*100=500
Q2) number of atoms in 10 g Na
first we need number of moles of sodium
moles =mass/molar mass
moles=10/23=0.43
now we know that moles=number of atoms /avogadro number
for number of atom the formula become
number of atom=moles*avogadro number
number of atom=0.43*6.023*10^23=2.6*10^23
Q3)number of molecule in 10 g of NaCl
again we need number of moles of NaCl
moles=given mass/molar mass
moles=10/58.5=0.17
now number of molecules=moles*avogadro number
number of molecules=0.17*6.023*10^23=1.02*10^23
Q4) avogadro number is the number of particles(atoms,molecules,ions) present in one mole of a substance its value is 6.023*10^23
Q5)Number of atoms in 4g of oxygen
again we need number of moles of oxygen
moles=mass/molar mass
moles=4/16=0.25
now number of atoms=moles*avogadro number
number of atoms=0.25*6.023*10^23 =1.5*10^23
Describe how you would measure the density of a boat (how would you predict if it would float )
Answer:
Please find the description below
Explanation:
The density of a substance refers to its mass per unit of its volume i.e the amount of a substance contained in a given volume. The density is calculated using the formula:
Density = mass/volume
Using this formula, with the known value for mass and volume of the boat, the density of the boat can be calculated.
An object will FLOAT on a liquid substance if its density is lower than that of the liquid while it will SINK if it has a higher density than that of the liquid.
In this case, with a known density of water, which is 1g/cm^3 or 1000kg/m^3,
a boat placed on water will FLOAT if its density is <1g/cm^3 (less than) while it will SINK if its density is >1g/cm^3 (greater than).
If I fill a tall glass with water and then transfer the water to a shorter glass, it appears there is more water. Is there more water?
What are some tips *from a girl* to get a girl to like you without making it obvious
this is an earth and space question worth 46 points plz answer Edwin Hubble was an American astronomer who pioneered the exploration of what type of space.
Answer:
He made human race know there were other galaxies in this universe
2. Which of the following statements correctly explains the difference between a theory and a scientific law?
O Scientific laws are not as well proven as theories.
O Scientific laws are statements about observed experimental facts, while theories are explanations of natural phenomena.
Theories are not as well proven as scientific laws.
O Scientific laws explain natural phenomena while theories are just guesses.
Answer:
pretty sure its Scientific laws are statements about observed experimental facts, while theories are explanations of natural phenomena.
The statement that correctly explains the difference between a theory and a scientific law is as follows:
Scientific laws are statements about observed experimental facts, while theories are explanations of natural phenomena.Thus, the correct option is B.
What is Scientific theory?A Scientific theory may be defined as a well-explained fact that is significantly associated with the natural world that has been constructed through the utilization of the scientific method, and which brings together many facts and hypotheses.
A Scientific theory is based on observation. It is proven but still testable in nature in order to derive evidence. It generally does not possess mathematical statements and deductions. Theories are explained on nature as well as natural phenomena.
Scientific law is based on unalterable facts or those facts that remain constant. It is proven as well as contains evidence to support the claim. It definitely possesses mathematical statements and deductions.
Therefore, the correct option for this question is B.
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When an atom of a Radioactive element emits alpha radiation, an atom of a different element is formed. A different element is formed because the radioactive element has lost...
Explanation:
its its originality as an atom has to be pure
A different element is formed because the radioactive element has lost its originality as a pure atom when a radioactive element emits alpha radiation.
What is a radioactive element?Some elements of unstable atomic nuclei undergo radioactive decay to form stable nuclei because of the presence of excess nuclear charge inside them are known as radioactive elements.
The stability of nuclei of an element can be estimated by neutron to proton ratio. The atomic number up to Z= 20 is stable nuclei and contains an equal number of protons and neutrons. As the atomic number starts to increase, the repulsion forces between protons increase.
Thus, the neutron-to-proton ratios of stable nuclei increase with increasing atomic numbers. If elements with the atomic number, Z > 83 and n/p > 1.5 and they will be most unstable and radioactive.
For example, Pu-240 emits an alpha particle and gets converted into U-236 which is completely different from the original nuclei.
²⁴⁰Pu₉₄ → ⁴He₂ + ²³⁶U₉₂
Therefore, the radioactive element lost its identity after disintegration.
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Please help Which of the following is the SI unit used to measure length? a.kilogram b.liter c.meter d.Kelvin
A. kilogram is the SI unit used to measure mass of body.
1 kilogram = 100 gramB. litre is the SI unit used to measure volume of substance.
1 litre = 10ˉ³ m³C. meter is the unit used to measure length of body.
1 meter = 100 centimetersD. Kelvin is the unit used to measure temperature of body.
1 K = -273.15 °CHence, (B) is the correct answer!
Cheers!
a glass of.water contains 500g of liquid and 500 ml of liquid what is the density
Answer:
Explanation:
density=mass/volume
density=500/500
=1g/ml
PLEASE ANSWER NOW!!! This chart shows what happens when each object is placed on a balance with a 10 kg weight on the other side. Which statement is best supported by the information in the chart? Object 1 is the heaviest object. Object 3 is heavier than Object 1. The weight is heavier than Object 2. The weight is the heaviest object.
Answer:
Balanced forces do not cause a change in motion. When balanced forces act on an object at rest, the object will not move. ... Forces that cause a change in the motion of an object are unbalanced forces. Unbalanced forces are not equal and opposite.
Explanation:
Any push or pull is a force. To describe a force, you must know two things. You must know the size of the force and the direction of the force. Suppose two teams are playing tug of war. Each team is pulling with equal force, but in opposite directions. Neither team can make the other team move. Forces that are equal in size but opposite in direction are called balanced forces.
tug of war balanced
Balanced forces do not cause a change in motion. When balanced forces act on an object at rest, the object will not move. If you push against a wall, the wall pushes back with an equal but opposite force. Neither you nor the wall will move. Forces that cause a change in the motion of an object are unbalanced forces.
tug of war unbalanced 1
Unbalanced forces are not equal and opposite. Suppose that one of the teams in tug of war pulls harder than the other team. The forces would no longer be equal. One team would be able to pull the other team in the direction of the larger force.
Force and Motion
More than one force can act on an object at the same time. If you hold a paper clip near a magnet, you, the magnet and gravity all exert forces on the paper clip. The combination of all the forces acting on an object is the net force. When more than one force is acting on an object, the net force determines the motion of the object. In this example, the paper clip is not moving, so the net force is zero.
How do forces combine to form the net force? If the forces are in the same direction, they add together to form the net force. Suppose you and a friend are asked to move a piano for the music teacher. To do this, you pull on one end of the piano, and your friend pushes on the other end. Together, your forces add up to enough force to move the piano. This is because your forces are in the same direction. Because the forces are in the same direction, they can be added together to determine the net force. In this case, the net force is 45 N, which is plenty to move a piano - if it is on wheels, that is!
net force piano
If two forces are in opposite directions, then the net force is the difference between the two forces, and it is in the direction of the larger force. Consider two dogs playing tug of war with a short piece of rope. Each is exerting a force, but in opposite directions.
Notice below that the dog on the left is pulling with a force of 10 N, and the dog on the right is pulling with a force of 12 N. Which dog do you think will win the tug of war? Because the forces are in opposite directions, the net force is determined by subtracting the smaller force from the larger one. In this case, the net force is 2 N in the direction of the dog on the right. Give that dog a dog biscuit!
Answer:
A. Object 1 is the heaviest
Hope it works!
Explanation:
why matter looks and feels different depending on the object
Answer:
because the volume
Explanation:
Which is more viscous - petrol or diesel?
Answer:
Petrol....follow me and mark me brainliest
Answer The answer to this question is diesel.
Explanation:
Hi there, hope this helps!
Some chemical reactants are listed in the table below. Complete the table by filling in the oxidation state of the highlighted atom.
Answer:
1. Cu = +2
2. O = – 2
3. C = +2
4. N = 0
Explanation:
Note:
A. The oxidation state of oxygen is always – 2 except in peroxides where it is – 1.
B. The oxidation state of Hydrogen is always +1 except in metallic hydrides where it is – 1.
Now let us solve the question given above.
1. CuO = 0 (ground state)
Cu + O = 0
O = – 2
Cu + (– 2) = 0
Cu – 2 = 0
Collect like terms
Cu = 0 + 2
Cu = +2
2. H2O = 0 (ground state)
2H + O = 0
H = +1
2(1) + O = 0
2 + O = 0
Collect like terms
O = 0 – 2
O = – 2
3. CO = 0 (ground state)
C + O = 0
O = – 2
C + (– 2) = 0
C – 2 = 0
Collect like terms
C = 0 + 2
C = +2
4. N2 = 0 (ground state)
2N = 0
Divide both side by 2
N = 0/2
N = 0
In coulombs, how much positive charge is there IN a barium nucleus? On a barium ion?
Answer:
The amount of positive charge in a barium nucleus is approximately 8.972 × 10⁻¹⁸ coulomb
Explanation:
The amount of positive charge there is in a barium nucleus is found as follows;
The atomic number of an element is equal to the number of proton present in the atom
The atomic number of barium = 56 = The number of protons in an atom of barium
The positive charge of a single proton is known as an elementary charge, e, given by the formula, e = F/N[tex]_A[/tex]
Where;
F = Faraday's constant
N[tex]_A[/tex] = The Avogadro's number
Therefore, e = 1.602 176 634 × 10⁻¹⁹ C
Which gives the positive charge, Q, of the protons of a barium nucleus as follows;
Q = Number of protons × e
Q = 1.602176634 × 10⁻¹⁹ × 56 ≈ 8.972 × 10⁻¹⁸ Coulomb per atom of barium.
The amount of positive charge in a barium nucleus ≈ 8.972 × 10⁻¹⁸ coulomb.
SHOW YOUR WORK!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
An experiment was conducted to find the mass of one mole of carbon atoms. The results of the experiment showed that a mole of carbon atoms had a mass of 15.78 g. The accepted value of a mole of carbon atoms is 16.00 grams. What is the percent error in this experiment?
Answer:
1.375%
Explanation:
Percent Error = measured value - accepted value/ accepted value x 100
Measured Value: 15.78
Accepted Value: 16.00
Work:
[tex]\frac{15.78-16.00}{16.00}[/tex] * 100
[tex]\frac{-.22}{16}[/tex] * 100 = -1.375
You cannot have a negative percentage. Therefore the answer is 1.375%
What are the charges on simple ions formed from atoms of group 2A elements
Explanation: Atoms in Group 2A have 2 valence electron and lose 2 electron to gain an octet. These cations have +2 charge. Transition Metal Cations Electrons are removed from ns subshell before the (n-1)d subshell Fe atom = [Ar]4s23d6 Fe2+ ion = [Ar]3d6 Fe3+ ion = [Ar]3d5 The 4s electrons have been removed.
A student lifts a bag from the floor to his or her shoulder 1.2m above the floor, using a force of 50N. How much work does the student do on the bag ?
60 J work does the student do on the bag.
The formula for work is as follows:-
[tex]W=F\times d[/tex]....(1)
Here, F is the force, and d is the distance moved in the direction of force.
Substitute 50 N for force and 1.2 m for distance in the equation (1) as follows:-
[tex]W=50\ N\times 1.2\ m\\\\=60\ Nm\\\\=60\ Joule[/tex]
Hence, the value of work is 60 J.
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A calorimeter made from a can is used to measure the calories in a peanut. During the experiment, the
measured calories were 35% of the true/accepted value given by references
Answer:
The heat generated per gram of sample in calories is 0.87 g
Explanation:
Given that,
A calorimeter made from a can is used to measure the calories in a peanut.
During the experiment, the measured calories were 35% of the true/accepted value given by references
Suppose, the mass of peanut is 0.4 g and find the
We need to calculate the heat generated per gram of sample in calories
Using formula of heat generated
[tex]q=\dfrac{q_{penut\ calorimeter}}{m_{peanut}}[/tex]
Put the value into the formula
[tex]q=\dfrac{0.35}{0.4}[/tex]
[tex]q=0.87\ g[/tex]
Hence, The heat generated per gram of sample in calories is 0.87 g
Which property is a physical property?
A:malleable
B:becomes moldy quickly
C:easy to digest
D:does not burn
Answer:
The answer is B. Becomes moldy quickly.
Explanation:
This is the most logical answer out of all of them an I took the test.
Which of the following is not a theory supporting global warming?
a.
It is predicted that the average temperature will rise 1.4° C or more over the next 100 years.
b.
Human activity has increased greenhouse gases.
c.
Over the last 100 years the earth has warmed by 0.74° C
d.
Carbon dioxide is an insignificant greenhouse gas.
A theory that is not supporting global warming is Carbon dioxide is an insignificant greenhouse gas. D is correct.
What is global warming?Global warming is the long-term heating of Earth’s surface observed since the pre-industrial period (between 1850 and 1900) due to human activities, primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere. This term is not interchangeable with the term "climate change."
Our world is heating up. Because of global warming, temperatures are increasing and extreme weather is becoming more common. If we don't take preventative action now, future generations will be faced with warmer temperatures, as well as higher sea levels, extreme weather events, crop failures, extinctions, and other devastating effects.
Greenhouse effect is the reason for global warming and it happens because of absorption of gases like CO₂ and CH₄ in our environment.
Therefore, A theory that is not supporting global warming is Carbon dioxide is an insignificant greenhouse gas. D is correct.
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