Answer:
i hope it will help you
Explanation:
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How is the mass of 1 mole of an element determined? O A. It is equal to the atomic mass times Avogadro's number. O B. It is the same as the element's atomic mass, but in grams. O c. It is equal to the atomic number times Avogadro's number. O D. It is the same as the element's atomic number, but in grams.
Answer:
Avogadro's number is the number of particles in one mole of anything. In this context, it is the number of atoms in one mole of an element. It's easy to find the mass of a single atom using Avogadro's number. Simply divide the relative atomic mass of the element by Avogadro's number to get the answer in grams.
Answer:
D. It is the same as the element's atomic mass, but in grams.
Explanation:
other answer didn't give the actual option lol
Calculate the number of hydrogen atoms in 33.0 g CH4
Answer:
The number of hydrogen atoms is 4.96x10²⁴.
Explanation:
The number of atoms can be found with the following equation:
[tex] n = N*\eta_{H} [/tex]
Where:
N: is the Avogadro's number = 6.022x10²³ atoms/mol
η: is the number of moles of hydrogen
n: is the number of hydrogen atoms
First, we need to find the number of hydrogen moles. The number of moles of CH₄ is:
[tex] \eta_{CH_{4}} = \frac{m}{M} [/tex]
Where:
m: is the mass of methane = 33 g
M: is the molar mass of methane = 16.04 g/mol
[tex] \eta_{CH_{4}} = \frac{33 g}{16.04 g/mol} = 2.06 mol [/tex]
Now, since we have 4 hydrogen atoms in 1 mol of methane, the number of moles of hydrogen is:
[tex] \eta_{H} = 2.06\: mol\: CH_{4}*4 \frac{mol\: H}{mol \: CH_{4}} = 8.24 mol [/tex]
Hence, the number of hydrogen atoms is:
[tex]n = N*\eta_{H} = 6.022 \cdot 10^{23} \: atoms/mol*8.24 mol = 4.96 \cdot 10^{24} atoms[/tex]
Therefore, the number of hydrogen atoms is 4.96x10²⁴.
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what happens to the atomic size of elements on moving from left to right in a period of modern periodic table?
Answer: the atomic size will decrease
Explanation:
Answer:
It will remain the same because it is moving up and down to and fro it can not increase nor decrease or else will become an ion
1. A potassium atom has a larger atomic radius than a sodium atom. What statement about potassium correctly explains this difference?
A) It has a larger nuclear charge
B) It has a lower electronegativity
C) It has more energy levels occupied by electrons
D) It has a lower ionization energy
2. Which of the following elements has the greatest electron affinity (largest negative value)?
A) Mg
B) Al
C) Si
D) P
E) S
3. The electron affinity of fluorine is essentially equal to
A) The negative of the ionization energy F
B) The ionization energy F-
C) The negative of the ionization energy F-
D) The ionization energy Ne
E) The negative of the ionization energy Ne
The electron affinity is the energy required to remove an electron from an atom to yield a negative ion.
We know that atomic size increases down the group as more shells are added. This is because, inter-electronic repulsion pushes the electrons in the outermost shell farther away from the nucleus. Hence potassium atom has a larger atomic radius than a sodium atom because It has more energy levels occupied by electrons.
Electron affinity increases across the period. The more nonmetallic an element is, the more negative its electron affinity. Hence, sulfur has the greatest electron affinity.
Electron affinity is the opposite of ionization energy. It therefore follows that, the electron affinity of fluorine is essentially equal to the negative of the ionization energy F.
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Which of these is correct please help
Answer:
NH4+
Explanation:
NH4+ is the acid and NH3 is the base, so NH4+ is the stronger acid.
HELP!! Which of the following phase changes occur at point B on the phase diagram shown below?
Boiling
Condensation
Freezing
Sublimation
Answer:
freezing
Explanation:
because condensation is gas to liquid boiling is liquid to gas and sublimation is solid to gas
Select all of the following reactions that are endothermic.
½N 2(g) + 3/2H 2(g) → NH 3(g) + 11.0 kcal/mole
H 2(g) + ½O 2(g) → H 2O(g), ΔH = -57.83 kcal/mole
½N 2(g) + O 2(g) + 8.1 kcal → NO 2(g)
½N 2(g) + ½O 2(g) → NO(g), ΔH = +21.6 kcal/mole
NH 3(g) → ½N 2(g) + 3/2H 2(g), ΔH = +11.0 kcal/mole
Answer:
½N 2(g) + O 2(g) + 8.1 kcal → NO 2(g)
½N 2(g) + ½O 2(g) → NO(g), ΔH = +21.6 kcal/mole
NH 3(g) → ½N 2(g) + 3/2H 2(g), ΔH = +11.0 kcal/mole
General Formulas and Concepts:
Thermochemistry
Endothermic vs ExothermicEnthalpyExplanation:
An endothermic reaction would have heat or energy gained in the final stage of the reaction.
This means that our enthalpy would be positive and heat/energy would be added as a reactant.
Out of all the answer choices, we see that only these have heat/energy added in the reactant side or the enthalpy being positive:
½N 2(g) + O 2(g) + 8.1 kcal → NO 2(g)
½N 2(g) + ½O 2(g) → NO(g), ΔH = +21.6 kcal/mole
NH 3(g) → ½N 2(g) + 3/2H 2(g), ΔH = +11.0 kcal/mole
Topic: AP Chemistry
Unit: Thermochemistry
Which statement is true about the atoms in helium gas?
They have strong attractions to one another.
They travel in circular paths.
They are arranged in an orderly pattern.
They are not closely packed.
Answer: The answer is they are not closely packed
Explanation: HOPE THIS HELPS!!
Which one is wrong I did them but it’s saying I got partial credit
To begin the experiment, Xavier washed his hands and put on safety goggles. He then measured 120 milliliters of tap water, 2.5 milliliters of baking soda, and 2.5 milliliters of citric acid. The initial temperature of the water was 23.5°C.
Next Xavier added the baking soda and citric acid to the water. The mixture immediately began to bubble vigorously, which lasted for about 30 seconds. The new temperature of the mixture was 17.7°C.
Is a chemical reaction taking place during Xavier’s experiment? How do you know?
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Answer:
Yes a chemical reaction is taking place.
Explanation:
There is a change in temperature along with bubbling. All signs of a chemical reaction.
6. The melting point of iodine is 114°C and the boiling point is 183°C. What state will Iodine be at each of these temperatures:
70°C –
210°C –
185°C –
127°C –
0°C –
Answer:
the answer is known as 210°c
Sodium and chlorine combine to form table salt.
2Na(s) + Cl2(g) → 2NaCl(s)
Does this reaction obey the law of conservation of mass?
Answer:
yes it does
Explanation:
because the ratios on the reactants and products are equal
The reaction 2Na(s) + Cl₂(g) → 2NaCl(s) obeys the law of conservation of mass.
Yes, this reaction obeys the law of conservation of mass. The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction; it is only rearranged.
In the given reaction, we have 2 sodium atoms (Na) on the left side and 2 sodium atoms (Na) on the right side. Similarly, we have 2 chlorine molecules (Cl₂) on the left side and 2 chlorine atoms (Cl) on the right side. Therefore, the number of atoms of each element is balanced on both sides of the reaction.
Additionally, the total mass of the reactants (2Na + Cl₂) is equal to the total mass of the product (2NaCl). The coefficients in the balanced equation represent the stoichiometric ratios, ensuring that the mass is conserved.
Hence, the reaction 2Na(s) + Cl₂(g) → 2NaCl(s) obeys the law of conservation of mass.
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Using the idea of Dobereiner's triads, what conclusion could have been made about magnesium,
had beryllium and calcium already been discovered?
Answer:
Explanation: Using the idea of Dobereiner's triads, what conclusion could have been made about magnesium,
had beryllium and calcium already been discovered?
What is the purpose of the lab
How many sodium (NA) Atoms are in Methylene?
None
Explanation:
methylene is an organic compound comprising and of One carbon and two hydrogens
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what are the byproduct obtained during fermentation of glucose
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Answer:
during the fermentation of glucose carbon dioxide and alcohol are produced
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While a balloon is being filled, if the temperature of the air in the balloon increases, what happens to it’s volume?
When heating up, the balloon slowly rises and flies up in the air again. Explanation: The volume of the balloon decreases by the low temperature, because the gas inside is cooled down. When heated up, the pressure in the balloon rises, the balloon expands, and will reach to its original shape.
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an oil drum weights 11.8kg. when it is filled, octane it weighs 55.32kg. how many molecules of pentane c5h12 exist in this oil drum?
Question: an oil drum weights 11.8kg. when it is filled, pentane it weighs 55.32kg. how many molecules of pentane c5h12 exist in this oil drum?
Answer:
3.64×10²⁶ molecules
Explanation:
Applying,
n = M/M.M................... Equation 1
Where n = number of moles of pentane, M = mass of pentane, M.M = reacting mass of pentane
From the question,
Given: M = 55.32-11.8 = 43.52 kg = 43520 g
Constant: M.M of octane (C₅H₁₂) = [(12×5)+(1×12)] = 60+12 = 72 g/mol
Substitute these values into equation 1
n = 43520/72
n = 604.44 moles
Therefore,
number of molecules = n×(6.02×10²³)
number of molecules = 604.44(6.02×10²³)
number of molecules = 3.64×10²⁶ molecules
CH3 CH2 CH2 OH + H2SO4
Get the product and answer the following questions :
I. A + HCl
II. A --> Combustion ( what product does it form. Write out the equation )
III.A ---> Hydrogenation (what product does it form. Write out the equation )
Note : A represents the product gotten from the reaction between
CH3 CH2 CH2 OH and H2SO4
Answer:
propene and hydrogen is product
When propanol is heated with concentrated sulphuric acid at 443 K, dehydration takes place and prop-1-ene is formed. In this reaction concentrated sulphuric acid acts as a dehydrating agent.
I. A + HCl gives )-gives 2-chloropropane
II. A --> Combustion ( what product does it form. Write out the equation propene ozonide
III.A ---> Hydrogenation (what product does it form. Write out the equation )propanol
fill in the blanks-
Heating of zinc oxide is a change.
Answer:
63e52863
Explanation:
he he he
HELP ITS DUE SOON PLEASEE
Identify the type of chemical reaction for each of the following:
SnO2(aq) + 2H2(g) → Sn(s) + 2H2O(g)
AgNO3(aq) + KI(aq) → AgI(s) + KNO3(aq)
2Fe(s) + 3Br2(l) → 2FeBr3(s)
3H2SO4(aq) + 2Fe(s) → Fe2(SO4)3(aq) + 3H2(g)
2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g)
4Al(s) + 3O2(g) → 2Al2O3(s)
2KI(l) → 2K(s) + I2(s)
3CaCl2(aq) + 2Na3PO4(aq) → Ca3(PO4)2(s) + 6NaCl(aq)
The options are:
Single replacement
Double replacement
Decomposition
Formation
Hydrocarbon combustion
Answer:
SnO2(aq) + 2H2(g) → Sn(s) + 2H2O(g) - Redox reaction
AgNO3(aq) + KI(aq) → AgI(s) + KNO3(aq) - double replacement reaction
2Fe(s) + 3Br2(l) → 2FeBr3(s) - Formation
3H2SO4(aq) + 2Fe(s) → Fe2(SO4)3(aq) + 3H2(g) - Single replacement
2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g) - Hydrocarbon combustion
4Al(s) + 3O2(g) → 2Al2O3(s) - Formation
2KI(l) → 2K(s) + I2(s) - Decomposition
3CaCl2(aq) + 2Na3PO4(aq) → Ca3(PO4)2(s) + 6NaCl(aq) - Double replacement
Explanation:
In an oxidation - reduction reaction, the oxidation number of the species involved in the reaction changes from left to right. One specie is oxidized while the other is reduced. E.g in SnO2(aq) + 2H2(g) → Sn(s) + 2H2O(g) - Sn^2+ was reduced while H2 was oxidized.
For a single replacement reaction, one specie is replaced in the reaction e.g H^+ is replaced by Fe^2+ in the reaction, 3H2SO4(aq) + 2Fe(s) → Fe2(SO4)3(aq) + 3H2(g) .
In a double replacement reaction, the ions on the reactant side exchange partners at the product side e.g 3CaCl2(aq) + 2Na3PO4(aq) → Ca3(PO4)2(s) + 6NaCl(aq)
In a formation reaction, two reactants combine to form a product. E.g 2Fe(s) + 3Br2(l) → 2FeBr3(s)
In a decomposition reaction, a compound breaks down to yield its components e.g 2KI(l) → 2K(s) + I2(s)
Hydrocarbon combustion refers to the reaction of a hydrocarbon compound with oxygen e.g 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g)
Under which conditions do
metamorphic rocks form during regional metamorphism?
Answer:
Under regional metamorphism, metamorphic rocks are formed as a result of transformation of large areas of previously existing rocks under the influence of a large amount of heat and pressure which are created by tectonic forces.
Explanation:
Metamorphism is the phenomenon in the formation of metamorphic rocks whereby rocks are changed by heat and pressure. Now, during this process called metamorphism, rocks are bound to change either physically and chemically into a new rock. Now, there are two types of metamorphism namely;
Contact metamorphism and regional metamorphism.
We are concerned with regional metamorphism and it is defined as metamorphic rocks formed as a result of transformation of large areas of previously existing rocks under the influence of a large amount of heat and pressure which are created by tectonic forces.
help please i am confused
It is pholem or phloem
Answer:
phloem I believe
Explanation:
dictionary
how many moles of H2O are used to make 3.12 moles of NH3
Answer:
4.73 mol NH
Explanation:
What we're doing here is calculating basic mole-mole relationships, something that you'll be doing quite a bit!
The steps to solving mole-mole problems like this are
write the balanced chemical equation for the reaction (this is given)
divide the number of moles of the given known substance (3.55) by that substance's coefficient in the chemical equation (3)
multiply that number by the coefficient of the substance you're trying to find (4)
Using simple dimensional analysis, it looks like this:
Answer:
4.68 H2O is needed to make 3.12 moles of NH3
Explanation:
Using stoichiometry, we can convert Moles of NH3 into Moles of H20
since we're converting moles to moles, we take the given mole of NH3
3.12, and multiply it by the Mole ratio, which in this case is (H20/NH3) or (6/4)
so then: 3.12 * 6/4 = 4.68 mols of H2O
What is the definition of a Brønsted-Lowry base? O A. A Brønsted-Lowry base transfers a proton to something else. OB. A Brønsted-Lowry base accepts a proton from something else. C. A Brønsted-Lowry base donates an electron pair to something else. O D. A Brønsted-Lowry base accepts a hydroxide ion from something else.
Answer:
the answer is option B it is a proton acceptor
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Answer:
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Describe how you would find out whether copper(ii) oxide was a catalyst for the decomposition of hydrogen peroxide solution. You need to show not only that it speeds the reaction up, but that it is chemically unchanged at the end.
Answer:
ds
Explanation:
sds
Based on the Lewis/electron dot representation
of the two atoms, predict the ratio of metal
cationic (+) atom to nonmetal anionic (-) atom in
the compound.
.Ca.
.P.
A. 1:1
B. 3:2
C. 2:1
D. 3:1
Can someone plz tell me how to do this.
Answer:
B or C think so
The concentration of hydroxide ions in the antacid, milk of magnesia, is 5.3 × 10−4 M. Calculate the concentration of hydronium ions at 25°C.
Answer:
1.89 × 10^-11 M
Explanation:
Recall that;
[H^+] [OH^-] = 1 × 10^-14
[H^+] = concentration of hydronium ions
[OH^-] = concentration of hydroxide ion
Where [OH^-] = 5.3 × 10−4 M
[H^+]= 1 × 10^-14/5.3 × 10−4
[H^+]= 1.89 × 10^-11 M
Milk of magnesia, with a concentration of hydroxide ions of 5.3 × 10⁻⁴ M, has a concentration of hydronium ions of 1.9 × 10⁻¹¹ M.
Milk of magnesia (Mg(OH)₂) is an antacid, in which the concentration of hydroxide ions is 5.3 × 10⁻⁴ M.
We can calculate the concentration of hydronium ions at 25°C using the following expression.
[tex][H_3O^{+} ][OH^{-} ] = Kw = 1.0 \times 10^{-14} \\\\[H_3O^{+} ] = \frac{1.0 \times 10^{-14} }{[OH^{-} ]} = \frac{1.0 \times 10^{-14} }{5.3 \times 10^{-4} } = 1.9 \times 10^{-11} M[/tex]
where,
Kw is the ionic product of waterSince [H₃O⁺] < 10⁻⁷ M, the milk of magnesia is basic.
Milk of magnesia, with a concentration of hydroxide ions of 5.3 × 10⁻⁴ M, has a concentration of hydronium ions of 1.9 × 10⁻¹¹ M.
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