Answer:
The total mass of the reactants equals the total mass of the products.
Explanation:
The true statement for all chemical reactions is that the total mass of the reactants equals the total mass of the products.
What is chemical reaction?Chemical reactions are those reactions in which reactants react with each other and converted into products for the completion of the reaction.
Let us assume a chemical reaction:
A + B → C + D
Where, A & B are reactants which are converted into products C & D. Means mass of reactants will convert into the mass of products as it follows the law of conservation of mass.
So, total mass of the reactants equals the total mass of the products.
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A factor that does no change in an experiment is the.
a. Controlled variable
b. Data
c. Inconstant
d. Independent variable
Answer:
A. Controlled variable
Explanation:
a controlled variable or a constant variable is a variable that doesnt change during an experiment
From a 2.875 g sample containing only iron, sand, and salt, 0.660 g of iron and 1.161 g of sand were separated and recovered. What was the percent of salt in the original sample
Answer:
36.66%
Explanation:
Step 1: Given data
Mass of iron: 0.660 gMass of sand: 1.161 gMass of the sample: 2.875 gMass of salt: ?Step 2: Calculate the mass of salt
The mass of the sample is equal to the sum of the masses of the components.
m(sample) = m(iron) + m(sand) + m(salt)
m(salt) = m(sample) - m(iron) - m(sand)
m(salt) = 2.875 g - 0.660 g - 1.161 g
m(salt) = 1.054 g
Step 3: Calculate the percent of salt in the sample
We will use the following expression.
%(salt) = m(salt) / m(sample) × 100%
%(salt) = 1.054 g / 2.875 g × 100% = 36.66%
The percent of salt in the original sample containing only iron, sand, and salt is 36.66%.
What is salt?Salt is a mineral made up of primarily sodium chloride.
Seawater contains a vast amount of salt.
Given,
The total mass of the sample is 2.875 g
Mass of iron is 0.660 g
Mass of sand is 1.161 g
Step 1: To find the mass of salt
The total mass of the sample = the sum of the masses of the compounds
m(sample) = m(iron) + m(sand) + m(salt)
2.875 g = 0.660 g + 1.161 g + m(salt)
m(salt) = 2.875 g - 0.660 g - 1.161 g
m(salt) = 1.054 g
Step 2: Calculate the percent of salt in the sample
[tex]\%(salt) = \dfrac{m(salt) }{m(sample)} \times 100\%\\\\\\\%(salt) = \dfrac{1.054 g }{2.875 g} \times 100\% = 36.66\%[/tex]
Thus, the percentage of salt in the sample is 36.66%.
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Express 2.99 x 108 m/s (the speed of light) in decimal notation (i.e., express the
number without using scientific notation
Answer:
speed of light = 299,000,000 m/s
Explanation:
The speed of light in vacuum, denoted as c, is a universal physical constant which unlike space and time, is independent of the observer. It is a constant that is important in many fields of science. Its exact value is given as 299,792,458 metres per second.
In scientific notation, it is approximately given as 2.99 x 10⁸ metres per second.
2.99 x 10⁸ metres per second = 2.99 x 100000000 = 299,000,000 m/s
Therefore, when expressed in decimal notation, the speed of light = 299,000,000 m/s.
What is the volume of a sample of matter with a density of 6 and a mass of 6 cm3?
Answer:
We have the final answer as
1.0 cm³Explanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\[/tex]
From the question
mass = 6 g
density = 6 g/cm³
It's volume is
[tex]volume = \frac{6}{6} = 1 \\ [/tex]
We have the final answer as
1.0 cm³Hope this helps you
If ΔH vaporization of water (H2O) is 40.7 kJ/mol,
and the ΔS for vaporization of H2O is 109 J/mol K,
what is ΔG for water vaporization at 350K?
Include units.
Answer:
2.6 kJ/mol
Explanation:
Step 1: Given data
Standard enthalpy of vaporization of water (ΔH°): 40.7 kJ/molStandard entropy of vaporization of water (ΔS°): 109 J/mol.KAbsolute temperature (T): 350 KStandard Gibbs free energy of vaporization of water (ΔG°): ?Step 2: Calculate ΔG°
We can calculate ΔG° using the following expression.
ΔG° = ΔH° - T × ΔS°
ΔG° = 40.7 kJ/mol - 350 K × 0.109 kJ/mol.K
ΔG° = 2.6 kJ/mol
The change in Gibbs free energy, ΔG for the water is 2.55 KJ/mol
Data obtained from the questionFrom the question given above, the following data were obtained:
Standard enthalpy of vaporization of water (ΔH°) = 40.7 kJ/molStandard entropy of vaporization of water (ΔS°) = 109 J/Kmol = 109 / 1000 = 0.109 KJ/Kmol Absolute temperature (T) = 350 KStandard Gibbs free energy (ΔG°) =? How to determine the Gibbs free energy, ΔG°The Gibbs free energy, ΔG° can be obtained as illustrated below:
ΔG° = ΔH° – TΔS°
ΔG° = 40.7 – (350 × 0.109)
ΔG° = 40.7 – 38.15
ΔG° = 2.55 KJ/mol
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Complete the chemical combustion reaction of naphthalene, which
demonstrates the conservation of mass.
C10H8 + 1202 >>
Answer:
[tex]C_{10}H_{8}+12O_2\rightarrow 10CO_2+4H_2O[/tex]
Explanation:
Hello,
In this case, since combustion reactions yield carbon dioxide and water via the following equation:
[tex]fuel+O_2\rightarrow CO_2+H_2O[/tex]
In such a way, for naphthalene, its combustion reaction is:
[tex]C_{10}H_{8}+12O_2\rightarrow 10CO_2+4H_2O[/tex]
Whereas we see ten carbon atoms, eight hydrogen atoms and twenty four oxygen atoms at both reactants and products as a proof of the law conservation of mass.
Regards.
1
Select the correct answer.
Which statement about the relationship between laws, hypotheses, and theories is true?
A.
Laws that remain true over an extended period of time are considered theories.
B.
A theory that holds true for a long time is considered a law.
C.
If a law is not contradicted after a lot of testing, it may be considered a hypothesis.
D.
If a hypothesis is not contradicted after a lot of testing, it may be considered a law.
Answer:
the answer is D
Explanation:
Students observed cells under the microscope. They observed that the cells had a cell wall, cell membrane,
nucleus, and many chloroplasts.
Which observation helps students identify the type of cell observed?
A The presence of a nucleus means the cells are from a plant.
B The presence of a cell membrane means that the cells are from an animal.
C The presence of chloroplasts means that the cells are from a plant.
D The presence of a cell wall means that the cells are from an animal.
Answer:
option B is the right answer
Be sure to answer all parts. Calculate the mass of each product formed when 70.76 g of diborane (B2H6) reacts with excess water: B2H6(g) + H2O(l) → H3BO3(s) + H2(g) [unbalanced] Mass of H3BO3: g Mass of H2: g
Answer:
A. 313.37 g of H3BO3.
B. 30.33 g of H2.
Explanation:
We'll begin by writing a balanced equation for the reaction. This is given below:
B2H6 + 6H2O → 2H3BO3 + 6H2
Next, we shall determine the mass of B2H6 that reacted and the masses of H3BO3 and H2 produced from the balanced equation equation. This can be obtained as follow:
Molar mass of B2H6 = (2×11) + (1×6) = 22 + 6 = 28 g/mol
Mass of B2H6 from the balanced equation = 1 × 28 = 28 g
Molar mass of H3BO3 = (1×3) + 11 + (3×16) = 3 + 11 + 48 = 62 g/mol
Mass of H3BO3 from the balanced equation = 2 × 62 = 124 g
Molar mass of H2 = 2×1 = 2 g/mol
Mass of H2 from the balanced equation = 6 × 2 = 12 g
From the balanced equation above:
28 g of B2H6 reacted to produce 124 g of H3BO3 and 12 g of H2.
A. Determination of the mass of H3BO3 produced from the reaction.
This can be obtained as follow:
From the balanced equation above,
28 g of B2H6 reacted to produce 124 g of H3BO3.
Therefore, 70.76 g of B2H6 will react to produce = (70.76 × 124)/28 = 313.37 g of H3BO3.
Therefore, 313.37 g of H3BO3 were obtained from the reaction.
B. Determination of the mass of H2 produced from the reaction.
This can be obtained as follow:
From the balanced equation above,
28 g of B2H6 reacted to produce 12 g of H2.
Therefore, 70.76 g of B2H6 will react to produce = ((70.76 × 12)/28 = 30.33 g of H2.
Therefore, 30.33 g of H2 were obtained from the reaction.
chemical test of acetylene in the laboratory
When measuring solid NaOH in pellet form, explain why you won’t be able to measure exactly 1.000 grams. What are the consequences of this?
Answer:
Explanation:
Pellet form of NaOH is highly hygroscopic . It absorbs moisture from air and its weight is increased by the time one tries to weigh one gram of it . Moreover it also reacts with carbon dioxide gas of atmosphere to form sodium carbonate .
2 NaOH + CO₂ = Na₂CO₃ + H₂0.
It also increases its weight .
The elemental analysis of an organic solid extracted from gum arabic showed that it contained 40.0% C, 6.7% H, and 53.3% O. A solution of 0.650 g of the solid in 27.8 g of the solvent diphenyl gave a freezing point depression of 1.56 °C. Calculate the molar mass and determine the molecular formula of the solid (kf for diphenyl is 8.00 °C/m). To earn full credit, clearly show your work with units and proper significant figures
Answer:
The molar mass of the organic solid is 119.9g/mol.
The molecular formula of an organic solid is C4H8O4
Explanation:
Step 1
We find the Molar mass
From the above question, we are given:
A solution of 0.650 g of the solid in 27.8 g of the solvent diphenyl gave a freezing point depression of 1.56 °C. Calculate the molar mass and determine the molecular formula of the solid (kf for diphenyl is 8.00 °C/m)
A freezing point depression = 1.56 °C.
Mass of organic solid= 0.650 g
Mass of diphenyl = 27.8 g
Converting to kilograms
1000g = 1kg
27.8g =
Cross Multiply
= 27.8g × 1 kg/1000g
= 0.0278kg
Boiling point constant = 8.00 °C/m
Molar mass of the organic compound = Boiling point constant × Mass of solid /Freezing point depression × Mass of diphenyl
Molar mass of the organic compound =
8.00 °C/m × 0.650g/1.56°C × 0.0278kg
= 5.2 g°C/m ÷ 0.043368 g°C
= 119.9040767 g/mol
Approximately = 119.9 g/mol
Step 2
Find the Molecular formula
Molecular formula = CxHyOz
Let x = Carbon, y = Hydrogen, z = Oxygen
For x = Carbon
Atomic mass of Carbon = 12.01078
x = % of Carbon in the compound × Molar mass of the organic compound/atomic mass of Carbon
x = 40% × 119.9 g/mol / (12.01078
x = 3.99
x = Approximately = 4
For y = Hydrogen
Atomic mass of Hydrogen = 1.007947
y = % of Hydrogen in the compound × Molar mass of the organic compound/Atomic mass of Hydrogen
x = 6.7% × 119.9 g/mol) / 1. 007947
x = 7.97
x is Approximately = 8
For z = Oxygen
Atomic mass of Oxygen = 15.99943
z = % of Oxygen in the compound × Molar mass of the organic compound/Atomic mass of Oxygen
z = 53.3% × 119.9 g/mol /15.99943
z = 3.99
z is approximately ≈ 4
Therefore,
The molar mass of the organic solid is 119.9 g/mol.
The molecular formula of an organic solid is C4H8O4
Why are atoms usually portrayed as spheres when most orbitals are not spherically shaped?
a. The shape of an atom depends on the shape of its nucleus, not on the shape of its orbitals.
b. The shape of an atom depends on the shape of the outer orbital which always spherical
c. The shape of an atom is obtained by superimposing all of its orbitals.
d. The shape of an atom is not important so it is easier to treat atoms as spheres.
Answer:
The shape of an atom is not important so it is easier to treat atoms as spheres.
Explanation:
In considering the shape of an atom, we do not consider the shape of the orbitals individually.
Hence, we do not seek to determine the exact shape of the atom, rather we simply treat the atom as spheres. Even though most orbitals are not spherically shaped.
A pure copper penny contains approximately 2.9×1022 copper atoms. Use the following definitions to determine how many ______ of copper atoms are in a penny. 1doz=12 1gross=144 1ream=500 1mol=6.022×1023 Part A dozens Express your answer in dozens to two significant figures.
Complete question is;
A pure copper penny contains approximately 2.9 × 10^(22) copper atoms.
1 doz = 12
1 gross = 144
1 ream = 500
1 mol = 6.022 × 10^(23)
Use these definitions to determine the following:
A) How many dozens of copper atoms are in a penny.
B) How many gross of copper atoms are in a penny
C) How many reams of copper atoms are in a penny.
D) how many moles of copper atoms are in a penny?
All answers can be rounded to two significant figures
Answer:
A) 2.4 × 10^(21) dozens
B) 2.01 × 10^(20) gross
C) 5.8 × 10^(19) reams
D) 0.048 mol
Explanation:
A) A dozen contains 12.
Therefore, 2.9 × 10^(22) copper atoms will contain;
(2.9 × 10^(22))/12 dozens = 2.42 × 10^(21).
In 2 significant figures, we have;
2.4 × 10^(21) dozens
B) 1 gross = 144
Therefore, 2.9 × 10^(22) copper atoms will contain;
(2.9 × 10^(22))/144 gross ≈ 2.01 × 10^(20) gross
C) 1 ream = 500
Therefore, 2.9 × 10^(22) copper atoms will contain;
(2.9 × 10^(22))/500 reams = 5.8 × 10^(19) reams
D) 1 mol = 6.022 × 10^(23)
Therefore, 2.9 × 10^(22) copper atoms will contain;
(2.9 × 10^(22))/(6.022 × 10^(23)) = 0.048 mol
3 points
What is the energy (Joules) of violet light with a frequency = 3.43 x 10^14
1/s? *
4.54x10^-19 J
1.99x10^-25 J
1.93 x 10^-48 J
O 2.27 x 10^-19 J
Pls help me
Answer:
4.54x10^-19 J
1.99x10^-25 J
1.93 x 10^-48 J
what were the limitations of Dobereiner's classifcation?
Answer:
Dobereiner could find only three triads; . i.e total of 9 elements only. However the total number of elements were more than that of those encompassed in Dobereiner's Triad
Explanation:
Answer:
Dobereiner could find only three triads; . i.e total of 9 elements only. However the total number of elements were more than that of those encompassed in Dobereiner's Triad. Thus, Dobereiner's could not be classify most of the elements known at that time
Explanation:
This work is not my own.... copied from google but hope this helps you.
a nucleus with 4 protons has a positive charge of _____ PLEASE LET ME KNOW
Answer:
if were talking about berylium then the answer should be 2 because it wants to move 2 spaces back (losing electrons) to become a nobel gas so the answer is 2+
Explanation:
it has 2 valence electrons YW :)
A nucleus with 4 protons has a positive charge of +2.
What are Protons?Protons may be defined as the type of sub-atomic particles that are present in the nucleus of an atom along with the neutrons. These sub-atomic particles possess a positive charge in nature. It may be thought that protons are discovered by Ernest Rutherford.
Beryllium has a nucleus with 4 protons, which means that it has an atomic number of 4. This element belongs to the alkaline earth metals in group 2. Beryllium has the capability to lose two electrons in order to attain a noble gas configuration and occupy stability. It has an electronic configuration [tex]1s^2, 2s^2[/tex]. So, in order to make it octet fulfilled, it loses two electrons and becomes positively charged.
Therefore, a nucleus with 4 protons has a positive charge of +2.
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In which of does the convection only occur in
A. Gases
B. Fluids
C. Liquids
D. Solids
Answer:
B. Fluids
I hope this helps!
Answer:
B
Explanation:
can some one help The function of the cell wall in a plant cell is Question 2 options: Allowing material to pass in and out of the cell Uses carbon dioxide, water and energy from the sun to make sugar Breaks sugar down into ATP which the cell can use for energy Provides support and protection for the cell
Answer:
the protection one
Explanation:
the cell wall acts a barrier
how many atoms are in 2 miles of h2o
Answer:
one mole of water contains 6.02 x 1023 MOLECULES of water.
But each molecule of water contains 2 H and 1 O atom = 3 atoms, so there are approximately 1.8 x 1024 atoms in a mole of water.
Explanation:
hope it helps you paigegeorge
How many atoms are in one body-centered cubic unit cell of a metal?
A) 1.
B) 2.
C) 3.
D) 4.
Answer:
Option B - 2
Explanation:
In Crystal lattices, there are different types of unit cells namely;
- Hexagonal Closest Packed (HCP)
- Face Centred Cubic (FCC)
- Body Centred Cubic (BCC)
- Simple Centred Cubic (SC)
Now, each of them have a coordination number and also number of atoms per unit cell.
For this question, we are restricted to the body-centered cubic (bcc) unit cell which has a coordination number of 8 and contains 2 atoms per unit cell.
Answer:
B) 2.
Explanation:
They have 8 1/8 atoms on the edge that add to get 1 atom. Plus one whole atom inside. 1+1=2
Which technology has helped improve scientists’ ability to gather scientific data about the movement of sea turtles? satellite tracking thermometers probeware microscopes?
Answer:either satellite tracking or probware.
Explanation:probate. Think its satalite tracking hope this helps.
Answer:
its satellite tracking
Explanation:
i got it right on edge
explain why division by zero is undefined
Answer:
Division by zero is undefined because there is no other number to divide it by.
Explanation:
Unlike 2/2, 2/0 doesn't have anything to divide the 2 by which makes it undefined and impossible to solve.
The division by zero is undefined, because whatever response we may give, we will then have to concur that the answer times 0 = 1, which is illogical because anything multiplied by zero is zero.
Why division by zero is undefined ?Since any attempt at definition results in a contradiction, the outcome of a division by zero cannot be defined. a=r*b. r*0=a. (1) (1) But because r*0=0 for all r, there is no solution to the equation unless a=0 (1).
Again, mathematicians have left zero divided by zero as an open problem because they are both equally valid and, to be honest, neither of them is consistent with the rest of mathematics.
Mathematically, it is impossible to divide a number by zero, just as in this illustration. Or, at the very least, there isn't currently a means to do that. Numerous attempts have been made to figure out how to divide by zero, as mathematicians are constantly looking for solutions to intriguing mathematical issues.
Thus, The division by zero is undefined, because whatever response we may give, we will then have to concur that the answer times 0 = 1.
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Which of the following is considered an ionic solid? a) (NH4)2CO3 b) CBr4 c) SeBr2 d) XeF4 e) None of the above is an ionic solid.
Answer: NH4)2CO3
Explanation:
Ionic solids are the solids that are simply held together by ionic bonds. Ionic bonds are lattices that are typically made up of oppositely charged ions and they usually possess a high melting point.
An example of ionic bond is NH₄)₂CO₃ which is referred to as Ammonium carbonate. This is a salt and it readily degrades upon heating to carbon dioxide and gaseous ammonia.
How many grams are there in 1.00x10 24 molecules of BCI3
Answer:
194.569 g
Explanation:
6.022×10^23 molecules = 117.17 g
1 molecules = 117.17/ 6.022×10^23
So, 1×10^24 molecules = (117.17×1×10^24)/(6.022×10^23)= 194.569 g
An unknown substance from planet X has a density of 10 g/ml. It occupies a volume of 80 ml. What is the mass of this unknown substance? *
Answer:
The answer is
800 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
density = 10 g/ml
volume = 80 ml
The mass of the substance is
mass = 10 × 80
We have the final answer as
800 gHope this helps you
3. Calculate each of the following:
a) kg of 4.6x1021 molecules of nitrogen dioxide
b) moles of chlorine atoms in 0.615 g of C2H4Cl2
c) number of hydride ions in 5.82 g of strontium hydride
Answer:
the answers are at the very bottom of each picture
Explanation:
i really hope this helps you:)
What is the mass, in grams, of the ethyl alcohol that exactly fills a 220 mL container? The density of ethyl alcohol is 0.789 g/mL. Group of answer choices 170 g 173.58 g 280 g 278.833967 g
Answer:
[tex]m=173.58g[/tex]
Explanation:
Hello,
In this case, since the density is the ratio of the mass and volume:
[tex]\rho =\frac{m}{V}[/tex]
For the given density and volume, the correct mass which fills the given volume is:
[tex]m=\rho *V=0.789g/mL*220mL\\\\m=173.58g[/tex]
Best regards.
What do metaloids share with nonmetals?
Answer:
Most metalloids have some physical properties of metals and some physical properties of nonmetals. They fall between metals and nonmetals in their ability to conduct heat and electricity. They are shiny like metals but brittle like nonmetals.
Explanation:
Given sulfur has an electron configuration of 1s22s22p63s23p4, what oxidation numbers would you expect for sulfur? (Hint: Think about how to achieve a full outer shell.)
Explanation:
1s2 2s2 2p6 3s2 3p4
Oxidation number refers to the number of electrons that an atom gains or loses as it forms a chemical bond with another element.
From the electronic configuration above, it is expected that sulphur has oxidation number of 2. This is because the p orbital can hold a maximum of 6 electrons. However, in the electronic configuration it is just holding 4. To complete it, it needs to gain 2 more electrons.
Answer:
+4, +6, –2
Explanation: