Answer:
Explanation:
Let the no in the ones place be x
And the no in the tens place be 10 - x
Original no = 10 ( 10 - x ) + x
= 100 - 10x + x
= 100 - 9x
Reversed no = 10 - x + 10 ( x )
= 10 - x + 10 x
10 + 9x
According to the question,
the new number formed exceeds the originals numbers by 54.
10 + 9x = 100 - 9x + 54
10 + 9x = 154 - 9x
By transposing,
9x + 9x = 154 - 10
18 x = 144
x = 144 / 18
x = 8
∴ Digit in ones place = x = 8
Digit in tens place = 10 - x = 10 - 8 = 2
So the number = 28
( You can also recheck it by adding the ones and tens digit
8 + 2 = 10
In the question, the sum of ones and tens digit in ten )
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A sample of 0.562 g of carbon is burned in oxygen in a bomb calorimeter, producing carbon dioxide. Assume both the reactants and products are under standard state conditions, and that the heat released is directly proportional to the enthalpy of combustion of graphite. The temperature of the calorimeter increases from 26.74 °C to 27.93 °C. What is the heat capacity of the calorimeter and its contents?
Answer:
The correct answer is 15.54 kJ per degree C.
Explanation:
The enthalpy change for one mole of a substance, which combines or burns with the oxygen under the standard conditions, that is, at 25 degree C and 1 bar pressure is known as the standard molar enthalpy of combustion. The amount of heat transferred can be calculated by using the formula, q = mcΔT -------------(i)
Here q is the amount of heat transferred, c is the specific heat, ΔT is the change in temperature, and m is the mass of the substance. As in case of bomb calorimeter, mass if considered constant, thus, for calorimeter the equation mentioned will become, q = cΔT ---- (ii)
The standard molar enthalpy of combustion for carbon is -393.5 kJ/mol, that is, -393.5 kJ per mole of heat is generated by burning one mole of carbon. The molecular mass of carbon is 12 gram per mole.
Thus, the number of moles of carbon equivalent to 0.562 grams of carbon can be determined as,
Number of moles of carbon = mass / molecular mas
= 0.562 grams / 12 gram per mole
= 0.047 mol
The heat generated by burning 0.562 grams or 0.047 mole will be,
q = ΔH° × number of moles
= (-393.51 kJ/mol) × 0.047 mol
= -18.49 kJ, the negative sign shows that the heat is produced.
To find heat capacity of calorimeter, put the value of q as -18.49 kJ, for ΔT as (27.93 °C - 26.74 °C) in the equation (ii)
18.49 kJ = c × (27.93 - 26.74)
c = 18.49 kJ/1.19 °C
c = 15.54 kJ/°C
4. (01.05 MC)
Rubbing alcohol evaporates from your arm quickly, leaving a cooling effect on your skin. How do the molecules of gas compare to the molecules as a liquid? (4 points)
The gas particles move faster, have the same molecular composition, and have weaker attractions between them than the liquid particles
The gas particles move faster than the liquid particles, and the bonds of the molecules are broken during evaporation to allow gas atoms to spread apart.
The gas particles move slower but have the same molecular structure and the same attraction between them as the liquid particles.
The gas and liquid particles move at the same speed, but the bonds of the molecules are broken during evaporation to allow the gas atoms to spread apart
Answer:
The correct option is;
The gas particles move faster, have the same molecular composition, and have weaker attractions between them than the liquid particles
Explanation:
The properties of the gas molecules in comparison to liquids are
1) The gas molecules are widely spread out
2) After evaporation and while in conditions favorable to the gaseous state, the kinetic energy of a gas is larger than the inter molecular attractive forces
3) A gas fills the container in which it is placed
For liquids
1) There are strong intermolecular forces holding the molecules together in a liquid
2) Liquid attractive forces in a liquid are strong enough to hold neighboring molecules
3) The volume of a liquid is definite.
Answer it answer it answer it
Answer:
[tex]\Large \boxed{\mathrm{A}}[/tex]
Explanation:
Rust formed from iron and oxygen combining is a chemical change, because in a chemical change, the resulting substance(s) will have different properties from the substance(s) before the chemical change.
I cant comment... So is it Right?
how many significant figures are in 820 400.0 L
Answer:
7 significant numbers
What does empirical fomula means with examples
A compound that has a sea of delocalized electrons has what type of bonding?
Answer:
Metallic Bonding
Explanation:
Metallic Bonding
In metallic bonds, the valence electrons from the s and p orbitals of the interacting metal atoms delocalize. That is to say, instead of orbiting their respective metal atoms, they form a “sea” of electrons that surrounds the positively charged atomic nuclei of the interacting metal ions.
Does Na2 gas posses metallic character? Explain your answer..
Explanation:
It contains Na2 molecules and the atoms in this molecule are held together by a purely covalent bond because the electronegativity of the two atoms is identical.Metallic bonding would not kick in until you make clusters of quite a few atoms. Such clusters would likely not be very stable because thermodynamically the larger the clump of material the more stable it gets. So they tend to coalesce until you have chunk of metal.Metallic bonding is in a sense a form of covalent bonding, but it is very collective (delocalized over a great many atoms) and electron deficient (there are more states than electrons to fill them up with, leading to conductive properties. This means that “a metallic bond” is a bit of an oxymoron like a forest with only one tree.Reply me in commentsYes, Na2 gas possesses a metallic character.
Does NA contain metallic bonds?In the stable state, metal sodium functions as an array of Na+ ions which can be surrounded by way of a sea of 3s electrons. However, it would be wrong to consider metal sodium as an ion when you consider that the ocean of electrons is shared by using all of the sodium cations, quenching the nice fee.
Sodium most effective has one valence electron. So, in metallic bonding, it is able to only donate one electron to be delocalized at some point of the structure. In steel bonding, the real bonding is the electrostatic force between the effective cations and the delocalized electrons.
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Polymers formed from amino acids are called _____. proteins carbohydrates lipids nucleic acids
Answer:
Proteins
Explanation:
Amino acids act as monomers (a single unit used to form polymers) , the polymer will be a long chain of individual amino acids. An amino acid chain forms a protein. These proteins are also known as peptides.
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Chemistry is often called the __________ science because it involves the study of the materials in the universe and the changes these materials undergo
Answer:
Central
Explanation:
Chemistry is often called the central science because of connects the physical sciences, life sciences and applied sciences.
Chemistry is the study of matter and changes undergone by matter. This makes chemistry to occupy a central place in many scientific disciplines including medicine, engineering, pharmacy, geology etc. Basic knowledge of chemistry is usually required by experts in these disciplines.
If you have a little air in a balloon, find the volume of the balloon if the mass is 0.6 g and the density of the air is 0.0012 g / mL
Hey there!:
Mass = 0.6 g
Density = 0.0012 g/mL
Volume = ??
Therefore :
Density = mass / Volume
0.0012 = 0.6 / V
V = 0.6 / 0.012
V = 500 mL
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A 46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the four substances whose properties are given, which is the most likely identity of this substance?
THIS IS THE COMPLETE QUESTION BELOW
46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the four substances whose properties are given, which is the most likely identity of this substance?
Substance Density (g/cm3) Melting Point (°C) Boiling Point (°C)
molybdenum 10.28 2,623 4,639
mercury 13.53 -39 357
hafnium 13.31 2,233 4,603
lead 11.34 327 1,749
A.
molybdenum
B.
mercury
C.
hafnium
D.
lead
Answer :
The correct option is OPTION C.
(C) Hafnium
Explanation;:
We were given the mass of substance as (m) = 46.9 g
The Volume of substance as (V) = 3.5 Cm^3
But we know Density of substance.= Mass/it's Volume
Then Density=46.9/3.5
=13.4g/Cm^3
From the questionthe given substance is solid at room temperature, and let us take Mercury as an example , Mercury is liquid at room temperature. ThenMercury cannot be the answer.
Base on the determined density which is 13.4 and the density of Hafnium also is 13.31 g/cm3 and it is solid at room temperature. Therefore, Hafnium is the only likely element here.
If each geometric shape represents a different type of atom, and atoms that are touching have chemically bonded with each other, which best describes this model? * 1. An element 2. A compound 3. A homogeneous mixture of two compounds 4. A heterogeneous mixture of two compounds 5. A homogeneous mixture of four elements 6. A heterogeneous mixture of four elements
Answer:
The correct option is;
3. A homogeneous mixture of two compounds
Explanation:
An homogeneous mixture is one where the components of the mixture are evenly dispersed such that the individual components cannot be seen to be isolated and distinguishable and having a constant composition of the constituents
The image displays three atoms (red circle, cyan triangle, and orange rectangle). The red circle appear to be bonded in pairs while the cyan triangles are bonded to the orange rectangles making a total of two compounds
The arrangement of the compounds in the mixture appear to be very evenly distributed to suggest an homogeneous mixture
The visibility of the compounds should be for an illustrative purpose.
What are half reaction
Answer:
When you don't have a complete reaction.
Explanation:
Happens a lot between a solvent and a solute. The solute may not bind well with the solvent I.e. water.
Find the density of a cube on Earth that weighs 1.5 kg and has a side-length of 10 cm.
Answer:
1.5g/cm³
Explanation:
density=mass÷volume
mass= 1.5kg (change into g) = 1500g
volume of the cube = 10×10×10 = 1000cm³
density= divide 1500g÷1000cm = 1.5g/cm³
Density= 1.5g/cm³YOUR WELCOME!
The density of the cube on Earth that weighs 1.5 kg and has a side length of 10 cm is 1.5g/cm³
What is density?"Density is the mass per unit volume. Density is a scalar quantity. It is denoted by d and the symbol for density is given as rho, a Greek symbol. Density is calculated as mass divided by volume."
density = mass / volume
The mass of the cube on earth is 1.5 kg
The side length of the cube is 10 cm.
The mass is given in kg. It is converted into grams.
mass= 1.5kg (change into g) = 1500g
A cube is a three-dimensional square, it has 6 faces, so its volume will be calculated completely.
Volume of the cube = 10×10×10 = 1000cm³
Putting the values in the formula of density
density= divide 1500g /1000cm = 1.5g/cm³
Thus, the density of the cube on Earth is 1.5g/cm³.
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What three things are required for a fire to start?
clearly distinguish between science and technology
Answer:
The words science and technology can and often are used interchangeably. But the goal of science is the pursuit of knowledge for its own sake while the goal of technology is to create products that solve problems and improve human life. Simply put, technology is the practical application of science.
Explanation:
Check the following images
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The pH of a solution decreases by 2.0. How does the hydronium ion concentration of the solution change? Increases to 2 times the original concentration increases to 100 times the original concentration decreases to one one hundredth. Of the original concentration decreases to one half. Of the original concentration
Answer:
The hydronium ion concentration increases to 100 times the original concentration
Explanation:
The pH of a solution is defined as the negative logarithm of the hydrogen or hydronium ion concentration of that solution. It is given by the expression below:
pH = -log[H₃O⁺] = log[H₃O⁺]⁻¹
Assuming the solution was at neutral with original pH = 7;
The new pH of the solution will be = 7 - 2 = 5
At pH = 7;
log[H₃O⁺]⁻¹ = 7
[H₃O⁺]⁻¹ = 10⁷
[H₃O⁺] = 10⁻⁷
At pH = 5
log[H₃O⁺]⁻¹ = 5
[H₃O⁺]⁻¹ = 10⁵
[H₃O⁺] = 10⁻⁵
10⁻⁵ = 10⁻⁷ * 10²
But 10² = 100
Therefore, the hydronium ion concentration increases to 100 times the original concentration
Answer:
B
Explanation:
On Edge
Scientists have changed the model of the atom as they have gathered new evidence. One of the atomic models is shown below. A purple ball in the center surrounded by overlapping concentric black ovals, each with a small green ball on each of the 6 ovals. What experimental evidence led to the development of this atomic model from the one before it? A few of the positive particles aimed at a gold foil seemed to bounce back. The colors of light emitted from heated atoms had very specific energies. Experiments with water vapor showed that elements combine in specific proportions. Cathode rays were bent in the same way whenever a magnet was brought near them.
Answer:
A few of the positive particles aimed at a gold foil seemed to bounce back.
Explanation:
Rutherford's experiment took the search for the structure of the atom a step further. In this experiment, a narrow beam of alpha particles emitted from a source was used to bombard a thin gold foil.
The scattering of the alpha particles was detected by a movable ZnS screen. It was found that most of the alpha particles followed a straight path through the gold foil but some were scattered through large angles and some even scattered backwards.
Following this experiment, Rutherford decided on his planetary model of the atom in which the nucleus is at the core of the atom with electrons moving round the nucleus in orbits. Rutherford was awarded a Nobel prize for this work.
Answer:
a
Explanation:
edge 2020
What is the formula of the ion hydrogen sulfite, which has a charge of -1
There are two types of ions in chemistry, one is cation and the other is anion. Anion is the negative charge ion. Therefore, the formula of hydrogen sulfite ion is HSO₃⁻
What is chemical Compound?Chemical Compound is a combination of ions, ions forms by combination of element and element forms by combination of atoms in fixed proportion.
According to our question the chemical compound from which hydrogen sulfite ion is coming is sulfurous acid that is H₂SO₃. So to get hydrogen sulfite ion we need to remove one hydrogen ion that is H⁺ from the chemical compound sulfurous acid.
The balanced reaction is
H₂SO₃[tex]\rightarrow[/tex]H⁺ + HSO₃⁻
From above reaction we can see that the charge over hydrogen sulfite ion is -1
Therefore the formula of hydrogen sulfite is HSO3-
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How many gram of zinc will have to be treated with dilute hydrochloric acid to liberate 1.85 dm³ of hydrogen at 27°C and 750mmHg?
Answer:
Explanation:
given
volume=1.85 d m^3
T=27 degree C=27+273 k=300 k
P=750 mmHg
mass of zinc=?
we know that PV=nRT
n=m/M
PV=mRT/M
M for zinc=65.4
PVM=mRT
m=PVM/RT
m=750*1.85*65.4/0.0821*300
m=90742.5/24.63
m=3684
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What is the independent variable of Smithers experience?
Please help controls and variables simpson? Smithers thinks that a special juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (in this case, they're supposed to staple a set of papers). Group A is given the special juice to drink while they work. Group B is not given the special...
Answer:
Smithers thinks that a special juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (in this case, they're ... Group A is given the special juice to drink while they work. Group ... 1. Control Group. Group B. 2. Independent Variable. volume of special juice.
Explanation:
Answer:
1. Group B
2. The juice
3. The number of stacks of paper
4. the juice did not help improve a quicker process
5. Group A can be given the juice, Group B can be given the juice without the special ingredient
USE QUIZLET FLASH CARDS IT CAN HELP YOU WITH A LOT OF QUESTION
11. Samantha was asked to measure out 10 g of salt in a lab. She mistakenly measures out 15 g instead. Calculate
the percent error. Make sure your answer has the correct number of significant figures!
Answer:
50%
Explanation:
Expected measurement required = 10g
Actual measurement observed = 15g
The percentage error is given as proportion the difference between the actual and expected measurement or values and the expected value value expressed as a percentage.
[(Actual - Expected) / Expected] × 100%
[(15 - 10) / 10)] × 100%
(5 / 10) × 100%
0.5 × 100%
50%
Therefore, the percentage error in the measurement is 50%
if 193 ml of chlorine gas was collected at 21 celsius, what volume would it have if the temperature dropped to 0 celsius
Answer:
New volume of chlorine gas (V2) = 179 ml (Approx)
Explanation:
Given:
Volume of chlorine gas (V1) = 193 ml
Temperature of chlorine gas (T1) = 21°C = 21 + 273 = 294 k
New temperature of chlorine gas (T2) = 0°C = 0 + 273 = 273 k
Find:
New volume of chlorine gas (V2) = ?
Computation:
Using charle's law
V1 / T1 = V2 / T2
193 / 294 = V2 / 273
V2 = 179.21
New volume of chlorine gas (V2) = 179 ml (Approx)
What is the atomic number of copper
Answer:
29
Explanation:
Copper is a chemical element with the symbol Cu and atomic number is 29
Explanation:
formula for soda glass
Answer:
composition of soda-lime glass is 73% SiO2 – 15% Na2O − 7% CaO − 4% MgO − 1% Al2O3 [129,132,133].
The Soda glass formula is SiO2, Na2O, CaO, Al2O3, K2O, SO3, MgO, Fe2O3, TiO2
Soda glass is a chemical compound that stands out for being the most widely used material to make windows, bottles, glasses, among others.
This compound is characterized by being chemically stable, reasonably hard, and extremely versatile because it can be recycled since it can be melted to make new products.
Its chemical formula is made up of other compounds such as:
SiO2, is Silicon OxideNa2O, is sodium oxideCaO, is calcium oxideAl2O3, is aluminum oxideK2O, is potassium oxideSO3, is sulfur oxideMgO, is magnesium oxideFe2O3, is iron oxideTiO2, is Titanium OxideAdditionally, the compounds found in the highest proportion in glass are SiO2 (74 atoms) and Na2O (13 atoms).
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Which element increases its oxidation number in this reaction? 3KOH + H3PO4 → K3PO4 + 3H2O
Answer:
The answer is "no changes in oxidation number "
Explanation:
Given equation:
[tex]3KOH + H_3PO_4 \longrightarrow K_3PO_4 + 3H_2O[/tex]
In the above-given equation, there are no changes in the oxidation number which can be defined as follows but first we defined the oxidation: In the chemical process, it requires the transfer of ions is oxidation. In particular, it means that products that supply electrodes are oxidized. In the given equation, when 3Potassium hydroxide reacts with phosphoric acid it will produce potassium phosphate and 3 moles of water.
Drag each tile to the correct image. Match each hydrocarbon class to its structure. carboxylic acid amine halocarbon alcohol
Answer:
1. Amine.
2. Alcohol.
3. Carboxylic Acid.
4. Halocarbon.
Explanation:
The correct answer according to the tile are Amine, Alcohol, Carboxylic acid, Halocarbon.
How can hydrocarbons be classified based on their structure?
Hydrocarbons can be classified as either aromatic or aliphatic compounds, depending on the presence of a benzene ring.
What is the most common classification of hydrocarbons?
Alkanes are hydrocarbons in which all of the bonds are single bonds. Alkenes are hydrocarbons that contain a carbon-carbon double bond.
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What element is depicted by the following electron configuration:
you can determine this by
adding the numbers of the sub-shells, 2+2+6+2+4=16the number on the last sub-shell, 4 means on the 4th main groupthe 3 before 3p4, tells us on the 3rd period, so the answer is Sulphur.What does light travel in?
Answer:
Light travels as a wave.
Explanation:
But unlike sound waves or water waves, it does not need any matter or material to carry its energy along. This means that light can travel through a vacuum—a completely airless space. (Sound, on the other hand, must travel through a solid, a liquid, or a gas.)
The pOH of a solution is 3.1. Which of the following is true about the solution? (1 point)
It is acidic and has a pH of 10.9.
It is basic and has a pH of 10.9.
It is acidic and has a pH of 6.2.
It is basic and has a pH of 6.2.
Answer:
The answer is option BExplanation:
To solve the question above we must first find the pH of the solution using the formula
pH + pOH = 14
pOH = 3.1
So we have
pH + 3.1 = 14
pH = 14 - 3.1
pH = 10.9
Since it's pH is 10.9 the solution is a basic solution since it's pH lies in the basic region.
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