Answers
Explaining the concept:
Molar mass of an element is the mass of 6.022*10²³ atoms of that element
a group of 6.022*10²³ atoms or molecules is called 1 mole of that specific element or compound
this number is so large that even though atoms are very small, 6.022*10²³ of them weigh several grams depending on the element the atom belongs to.
Atoms with a larger atomic number have more protons and neutrons than atoms with small atomic number; more protons and neutrons means that they have more matter and hence, more mass
that's why elements with a large atomic number are heavier
for example:
the molar mass (mass of 1 mole or 6.022*10²³ atoms) of hydrogen is approximately '1' grams per mole
whereas,
the molar mass of Carbon (C), (which has only 5 electrons more than hydrogen) is 12 grams per mole
Solving the question:
Finding the number of Moles:
We are given 5.4 grams of Boron (B)
the molar mass of boron is 11 grams per mole
To calculate the number of moles of an element, we divide the given mass by the molar mass
Number of moles = Given mass / Molar mass
Number of moles = 5.4 / 11
Number of moles = 0.5 (approx)
Finding the number of Atoms:
Now that we have the number of moles, we can easily find the number of atoms by dividing it by 6.022*10²³ (since a group of 6.022*10²³ atoms is 1 mole)
Number of Atoms = Number of moles * 6.022*10²³
Number of atoms = 0.5 * 6.022*10²³
Number of atoms = 3.011 * 10²³
Related Questions
When we measure the heat of combustion of glucose, C6H12O6, in a bomb calorimeter, what products are formed in the reaction
Answers
Answer:
H for the combustion reaction:
C6H12O6(s) + 6O2(g) => 6CO2(g) +6H2O(g)
The answer is -2.81 x 103kJ
Explanation:
The equation for the combustion of glucose is[tex]C_6H_1_2 O_6 + 6 O_2 ----- > 6 CO_2 + 6 H_2 O[/tex]
The products formed in this reaction are Carbon dioxide and Water.
What is Combustion?Combustion is a type of chemical reaction that takes place between substances that involves oxygen and produces heat and light in the form of a flame at which the rate of reactant combination is very high as the chemical reaction is in nature due to which more energy is released as a result of which the temperature of the reactant increases and accelerates the reaction even more.
It is a type of exothermic redox chemical reaction occur between a fuel that is a reductant and an oxidant. Burning is an another word for combustion.
Examples of combustion include a burning matchstick – when the matchstick is struck against a matchbox, the friction heats the head of the matchbox to a temperature at which the chemical reacts and produces more heat, which then goes out into the air and gets burnt in the flame.
For above statement, The products formed in heat of combustion of glucose are Carbon dioxide and Water
Thus, the equation for the combustion of glucose is[tex]C_6H_1_2 O_6 + 6 O_2 ----- > 6 CO_2 + 6 H_2 O[/tex]
The products formed in this reaction are Carbon dioxide and Water.
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Identify the possible issues if a sample in a spectrophotometer gives no reading. Select one or more: The wrong wavelength may be set. There may be an issue with the spectrophotometer. The sample may be placed impro
Answers
The question is incomplete; the complete question is;
Identify the possible issues if a sample in a spectrophotometer gives no reading. Select one or more:
The wrong wavelength may be set.
The sample may be placed improperly in the cuvette holder.
There may be an issue with the composition of the sample.
There may be an issue with the spectrophotometer
Answer:
The wrong wavelength may be set.
There may be an issue with the spectrophotometer
Explanation:
Substances do not absorb radiation at all wavelengths. The proper wavelength at which a substance absorbs must be used for a reading to be obtained from the spectrophotometer. If this is not done, no reading is obtained from the spectrophotometer.
Generally, if the spectrophotometer has an issue, it may display no reading until the machine is fixed.
The possible issues if a sample in a spectrophotometer gives no reading are:
The sample may be placed improperly in the cuvette holder. The wrong wavelength may be set.According to the given question, we are asked to identify the possible reasons why a spectrophotometer would give no reading when a sample is used on it.
As a result of this, it is important to note that it is possible that the sample may not have been placed correctly on the cuvette holder or the wrong wavelength may be set which would cause the no reading error to show.
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Why should you used distilled or deionized water instead of tap water when using AgNO3 as a test for anions?
Answers
Answer:
Why you use deonized water rather than tap water in this experiment? Because deonized water is pure and without contaminants that can affect the result of the experiment.
Explanation:
When using AgNO3 as the test anion, we used distilled or deionized water instead of tap water because deionized water is purer and free of contaminants that could affect the result of the experiment.
What is Distillation?Distillation is the process which involves the conversion of a liquid into water vapour and it condensed back to liquid form. It is the process in which separation of components of a mixture is based on different boiling points.
It is used to separate liquids from nonvolatile solids and also involve in the separation of alcoholic liquors from fermented materials or in the separation of two or more liquids having different boiling points, as in the separation of gasoline, kerosene, and lubricating oil from crude oil.
A plant that performs distillation is called a distillery while the apparatus used to perform distillation is called a still.
Thus, when using AgNO3 as the test anion, we used distilled or deionized water instead of tap water because deionized water is purer and free of contaminants that could affect the result of the experiment.
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How do you make a substance that glows in the dark? (for example glowsticks)
Answers
Answer:
Pour fluorescent dye and phenyl oxalate ester solution into the glass beaker with the hydrogen peroxide. Once the two solutions are combined, a chemical reaction will take place and cause the fluid to glow in the dark.
A sample of hydrogen sulfide has a mass of 73.00 g. Calculate the number of hydrogen sulfide molecules in the sample.
Answers
Answer:
1.29×10²⁴ molecules.
Explanation:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ molecules. Thus, 1 mole of Hydrogen sulfide (H2S) contains 6.02×10²³ molecules.
Next, we shall determine the mass of 1 mole of H2S. This is illustrated below:
1 mole of H2S = (2×1) + 32 = 34 g
Finally, we shall determine the number of molecules in 73 g of H2S as follow:
34 g of H2S contains 6.02×10²³ molecules.
Therefore, 73 g of H2S will contain =
(73 × 6.02×10²³) /34 = 1.29×10²⁴ molecules.
Thus, 73 g of H2S will contain 1.29×10²⁴ molecules.
The pH of a solution after a base and an acid have neutralized each other is ___.
Group of answer choices
A) 6
B) 8
C) 7
D) 0
Answers
Answer: B
Explanation:
2. Foliated rocks are characterized by
Answers
Alkali metals tend to be more reactive than alkaline earth metals because ________. Alkali metals tend to be more reactive than alkaline earth metals because ________. alkali metals have lower melting points alkali metals have lower densities alkali metals have greater electron affinities alkali metals have lower ionization energies Alkali metals are not more reactive than alkaline earth metals.
Answers
Answer:alkali metals have lower ionization energies
Explanation:
----Alkali metals tend to be more reactive than alkaline earth metals because alkali metals have lower ionization energies
Alkali metals are metals found in group 1 and examples are Lithium, Sodium and potassium having 1 electron in their outermost shell, Alkali earth metals on the other hand are found in group 2 of the periodic table and examp-les of which are Beryllium, magnesium, Calcium having 2 electrons in their outermost shells
Alkali metals are more reactive than the alkali earth metal due to the former having a lower ionization energy as we know , Ionization energy is the lowest energy it takes to remove a mole of electron from a mole of atom in gaseous sate, We can now see that it will take a very small amount to remove 1 valence electron than two valence electrons and the ability to easily loose electron makes an element more reactive.
Answer:
Alkali metals tend to be more reactive than alkaline earth metals because-
Explanation:
The more easily an electron is lost, the more reactive it is. Alkalines have 2 valence electron (electrons on the outer shell) whereas, Alkalis have 1 valence electron. So Alkaline's bond is stronger. An increase in density also increases the attraction force between nucleus and electron. Therefore Alkali are more reactive.
How many atoms are in 0.000045 grams of carbon?
Answers
Answer:
2.25E18
Explanation:
0.000045 g of Carbon x (1 mol C/ 12.01 g C) x (6.02 x 10E23 atoms / 1 mol C)
Start with the mass, then multiply it by the molar mass but put moles on the top and grams on the bottom to cancel out the grams. Then multiply it by Avogadros Constant to get atoms
What volume in mL of 0.300 M NaF would be required to make a 0.0715 M solution of NaF when diluted to 250.0 mL with water
Answers
Answer: The volume of 0.300 M NaF required is 59.6 ml
Explanation:
According to the dilution law,
[tex]C_1V_1=C_2V_2[/tex]
where,
[tex]C_1[/tex] = concentration of concentrated NaF solution = 0.300 M
[tex]V_1[/tex] = volume of pure concentrated Na F solution = ?
[tex]C_2[/tex] = concentration of diluted NaF solution= 0.0715 M
[tex]V_2[/tex] = volume of diluted NaF solution= 250.0 ml
[tex]0.300\times x=0.0715\times 250.0[/tex]
[tex]x=59.6ml[/tex]
Thus the volume of 0.300 M NaF required is 59.6 ml
Ne belongs to what group. a. noble gases, b.alkali metals, c. halogens, d. alkaline earth metals
Answers
2AgNO3The following chemical reaction takes place in aqueous solution: (aq)(aq)(s)(aq) Write the net ionic equation for this reaction.
Answers
Answer:
[tex]2Ag^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)[/tex]
Explanation:
Hello.
In this case, since the reaction is not given but a typical precipitation of silver from silver nitrate could be represented by its reaction with a soluble metallic sulfide or carbonate since silver carbonate and silver sulfide are insoluble, we can use for instance sodium carbonate to obtain:
[tex]2AgNO_3(aq)+Na_2CO_3(aq)\rightarrow Ag_2CO_3(s)+2NaNO_3(aq)[/tex]
Thus, since, silver nitrate, sodium carbonate and sodium nitrate are fully ionized by silver carbonate remains solid, the complete ionic equation is:
[tex]2Ag^+(aq)+2NO_3^-(aq)+2Na^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)+2Na^+(aq)+2NO_3^-(aq)[/tex]
Then, since nitrate and sodium ions are the spectator ions since they are at both reactants and products, the net ionic equation turns out:
[tex]2Ag^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)[/tex]
Best regards!
Phosphorus-32 has a half life of 14 days. If we begin with 40 mg how much is left after 42 days?
Answers
Answer:
0 mg
Explanation:
after 24 days all of it would be gone.
Phosphorus only has a 24 day life span.
When fertilizers enter surface water, they cause problems in the watershed by -
A. clogging narrow streams and preventing water from flowing properly.
B. increasing the amount of nutrients available to fish in lakes and streams.
C. causing rapid algal growth that decrease oxygen levels and choke aquatic life.
D. raising the water level in nearby rivers to levels leading to flooding.
Answers
C: Causing rapid algal growth that decreases oxygen levels and chokes aquatic life.
If this is incorrect, please, don't refrain to tell me. Thank you.
When fertilizers enter the water surface they cause brisk algal growth, which reduces the levels of oxygen and choke aquatic life.
What is eutrophication?It is the phenomenon by which the entire water body, or some part of it becomes enriched with nutrients and minerals, mainly the phosphorus and nitrogen. This generally takes place when the fertilizers used in fields get washed in the water body.
A common effect of eutrophication is algal blooms. The emergence of algal blooms results in the depletion of oxygen of the water body resulting in the choking of aquatic life.
Thus, the correct answer is option C.
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What happens to gas molecules if you take away heat?
Answers
Answer:
Taking energy away from a gas cooling it down may cause it to turn into a liquid or condense
Answer:
sold,liquidator gas
Explanation:
pressure| practicelmodel of matter| siyavula
what is unusual about the rotation of Venus
Answers
Answer:
Other planets rotate counterclockwise, but Venus rotates clockwise. Scientists believe this is due to an impact with a celestial body that occurred billions of years ago.
Explanation:
The rotation of Venus is unusual in a few ways like retrograde rotation,slow rotation.
1. Retrograde Rotation: Venus rotates in the opposite direction compared to most other planets in our solar system. While Earth and other planets rotate counterclockwise when viewed from the North Pole, Venus rotates clockwise. This retrograde rotation makes Venus unique among the planets in our solar system.
2. Slow Rotation: Venus rotates very slowly, taking around 243 Earth days to complete one rotation on its axis. This is longer than the time it takes for Venus to complete one orbit around the Sun, which is about 225 Earth days. As a result, a day on Venus (one complete rotation) is longer than its year (one orbit around the Sun).
Thus,these unique characteristics of Venus' rotation contribute to its distinct atmospheric conditions and extreme temperature variations between the day and night sides of the planet.
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______ play an important role in transport, they make movements possible and they help repair and build your body's tissues.
1. Lipids
2. Carbohydrates
3. Nucleic Acids
4. Proteins
Answers
Which is the attractive force of an ionic bond?
A. a charged atom to a similarly charged atom
B. a positively charged ion to an oppositely charged ion
C. one or more electrons to one or more protons
D. a charged atom to a neutral atom
Answers
NaBH4 is typically used in excess. Since the rate law for reduction of an aldehyde is first order in both NaBH4 and in aldehyde, how will using excess NaBH4 affect the overall reaction rate
Answers
Answer:
As the amount of NaBH4 is increased, the overall reaction rate also increases
Explanation:
This question tells us that NaBH4 is typically used in excess.
the rate law for reduction of an aldehyde is first order in NaBH4 and also in aldehyde,
We have The rate of reaction to be the equation below;
Rate = k[aldehyde][NaBH4]
The Rate of the reaction is directly proportional to NaBH4 concentration.
Therefore since they are directly proportional, when the amount of NaBH4 is increased, we will also have the overall reaction rate increase.
hen aqueous solutions of calcium bromide and sodium carbonate are combined, solid calcium carbonate and a solution of sodium bromide are formed. The net ionic equation for this reaction is:
Answers
Answer:
[tex]Ca^{2+}(aq)+CO_3^{2-}(aq)\rightarrow CaCO_3 (s)[/tex]
Explanation:
Hello.
In this case, we can first write the complete molecular equation as shown below:
[tex]CaBr_2(aq)+Na_2CO_3\rightarrow CaCO_3 (s) +2NaBr(aq)[/tex]
In such a way, since all the species but calcium carbonate remain in aqueous solution, they are successfully dissociated whereas the solid product remain undissociated:
[tex]Ca^{2+}(aq)+2Br^-(aq)+2Na^+(aq)+CO_3^{2-}(aq)\rightarrow CaCO_3 (s) +2Na^+(aq)+2Br^-(aq)[/tex]
Thus, we can cancel out bromide and sodium ions as spectator ions, in order to obtain the required net ionic equation:
[tex]Ca^{2+}(aq)+CO_3^{2-}(aq)\rightarrow CaCO_3 (s)[/tex]
Best regards!
The concentration of H3O+ in human sweat can be as low as 2.5 × 10-6. The concentration of OH- in the sweat is ________, and this solution is ________ (acidic, basic, neutral).
Answers
Answer:
[OH⁻] = 4.0 × 10⁻⁹ M
Acidic
Explanation:
Step 1: Given data
Concentration of H₃O⁺: 2.5 × 10⁻⁶ MStep 2: Calculate the concentration of OH⁻
We will use the following expression.
[H₃O⁺].[OH⁻] = Kw = 1.0 × 10⁻¹⁴
[OH⁻] = 1.0 × 10⁻¹⁴/[H₃O⁺] = 1.0 × 10⁻¹⁴/2.5 × 10⁻⁶ = 4.0 × 10⁻⁹ M
Step 3: Calculate the pH
We will use the following expression.
pH = -log [H₃O⁺] = -log 2.5 × 10⁻⁶ = 5.6
Since the pH < 7, the solution is acidic.
Susan has just moved into a new house. For some reason, she cannot get the grass to grow in her yard. She decided to grow small amounts of grass inside her house as part of an experiment. The first group of grass is exposed to light intensity of 400. The second group is exposed to light intensity of 1200. The graph below shows the results of Susan's experiment. 11. According to the graph, which of the following should be expected from Susan's two groups of plants?
A. The plants at a light intensity of 1200 will produce more oxygen than the plants at 400.
B. The plants at a light intensity of 1200 will perform only stage 1 of photosynthesis.
C. The plants at light intensity of 400 will produce more glucose than the plants at 1200.
D. The plants at a light intensity of 400 will grow more quickly than the plants at 1200.
Please help guys this is due tomorrow
Answers
Answer:
A
Explanation:
A magnet can be used to.
Bubble A. attract metal objects
Bubble B. measure the length of an object
Bubble C. measure the temperature of an object
Bubble D. measure the mass of an object
Answers
Answer:
D.measure the mass of an object
Answer: a attract metal objects
Explanation:
are you slow this is the easiest thing ever
What is the number of atoms in 2.65g of CH 4
Answers
Answer:
9.936x10^22 atoms of CH4
Explanation:
grams ----> mol
2.65 g CH4 if 1 mol of CH4 = 16.04 g CH4
2.65/16.04 = 0.165 mol of CH4
mol ------> atoms
1 mol = 6.022 x 10^23 atoms
0.165 mol x 6.022x10^23 = 9.936x10^22 atoms of CH4
help pls this is timed
Answers
Answer:
Explanation:
abything that is both mass and volume
Answer:
anything that has both mass and volume
what is a way that scientists communicate their
results to others?
HELP PLS!
Answers
Answer:
The main ways that scientists communicate research results is by publishing the results in journals. ... Some journals are peer-reviewed, meaning they only publish articles that pass a certain standard of quality -- peer-reviewed journals are usually for a specific audience, such as other scientists.
Explanation:
(1.6): What volume of oxygen, at 18°C and 750 torr, can be
obtained from heating 100gm of potassium chlorate, KCIO,?
Answers
Answer:
Volume of oxygen obtained = 30 L
Explanation:
Given data:
Mass of KClO₃ = 100 g
Pressure = 750 torr = 750/760 = 0.98 atm
Temperature = 18°C = 18+273 = 291 K
Volume of oxygen obtained = ?
Solution:
Chemical equation:
2KClO₃ → 3O₂ + 2KCl
Number of moles of KClO₃:
Number of moles = mass/molar mass
Number of moles = 100 g/ 122.55 g/mol
Number of moles = 0.82 mol
Now we will compare the moles of KClO₃ with oxygen.
KClO₃ : O₂
2 : 3
0.82 : 3/2×0.82 = 1.23 mol
Volume of oxygen:
PV = nRT
0.98 atm × V = 1.23 mol ×0.0821 atm.L/mol.K × 291 K
0.98 atm × V = 29.4 atm.L
V = 29.4 atm.L /0.98 atm
V = 30 L
Which of the following metals will not react with sulfuric acid (H2SO4(aq)) by single displacement reaction?
Zinc, magnesium, iron, silver
Answers
Answer:
Silver
Explanation:
Silver (Ag) will not react with sulfuric acid (H2SO4(aq)) by single displacement reaction. This is because in the electrochemical series (activity series), silver is below hydrogen and it's less reactive.
The other elements stated (Zinc, Magnesium, Iron) are higher than hydrogen in the activity series and will definitely displace hydrogen in single displacement reaction.
A single-displacement reaction is known as a chemical reaction which occurs which one element is actually replaced or displaced by another in a compound. We represent it as:
B + D-C ➡️ B-C + D
This will readily take place if B is more reactive than D, and it will finally give a more stable product.
guys please help me with this periodic table homework is really IMPORTANT FOR ME
Answers
Answer:
A, Chlorine, Cl
Explanation:
A 1.90-g sample of an oxide of bromine is converted to 3.188 g of AgBr. Calculate the empirical formula of the oxide. (molar mass for AgBr =187.78 g/mol)
a. BrO
b. Br2O
c. BrO
d. BrO3
e. None of these
Answers
Answer:
e. None of these
Explanation:
The oxide of Bromine (BrₐOₓ) produce "a" moles of Br that are equal to "a" moles of AgBr. The moles of AgBr are:
Moles AgBr:
3.188g AgBr * (1mol / 187.78g) = 0.01698 moles of AgBr = Moles of Br
These moles of Br weighs (Molar mass: 79.9g/mol):
0.01698 moles of Br * (79.9g / mol) = 1.36g of Br
Mass of Oxygen must be:
1.90g - 1.36g Br = 0.54g oxygen. In moles:
0.54g O * (1mol / 16g) = 0.03375 moles of O
Empirical formula is the simplest ratio of atoms in the molecule. Dividing in the moles of Br:
Br: 0.01698 moles of Br / 0.01698 moles = 1
O: 0.03375 moles of O / 0.01698 moles = 1.99 ≅ 2
That means empirical formula is:
BrO₂
And right option is:
e. None of theseThe empirical formula of the oxide would be [tex]BrO_2[/tex]
1.90 g of the oxide of bromine produces 3.188 g of AgBr
moles of 3.188 g AgBr = 3.188/187.78
= 0.017 moles
AgBr ---> Ag+ + Br-
Thus, mole of Br in AgBr = 0.017 moles
Mass of 0.017 Br = mole x molar mass
= 0.017 x 79.904
= 1.357 g
Mass of oxygen in the oxide of bromine = 1.90 - 1.357
= 0.543 g
mole of 0.543 oxygen = 0.543/16
= 0.0339 moles
mole of 1.357 g Br = 0.017
Dividing by the smallest:
Br = 0.017/0.017 = 1
O = 0.0339/0.017 = 1.99
Empirical formula = BrO2
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