Answer:
oil floats on water because it is heavier than water
Salt is no longer visible after stirring as salt dissolves in water
by filtration
At a distance of more than three feet from gun to target, there will generally not be signs of gunpowder on the target.
True
False
Why Don't Birds Get Electrocuted When They Land on Electric Wires?
Answer:
Birds are able to sit on electrical power lines because the electrical current essentially ignores the bird's presence and continues to travel through the wire instead of through the bird's body. A bird's body is not a good conductor of electricity.
hope i helped
helpe pls I will mark brainlest
Answer:
What is the question needing to be answered?
Explanation:
Usually with a scientific hypothesis, you ask the question in an if, then statement. For example: If it rains outside, then the ground will be wet. It's kind of like a cause and effect statement.
How many Hydrogen (H) Atoms are in Methylene?
Answer:
FOUR HYDROGEN ATOMS
Explanation:
Two C atoms, four H atoms, and two O atoms can also be arranged to form a methyl formate, which is used in manufacturing, as an insecticide, and for quick-drying finishes. Methyl formate molecules have one of the oxygen atoms between the two carbon atoms, differing from the arrangement in acetic acid molecules.
The Methylene group has 2 hydrogen. -CH2
the valency of both Oxygen and magnesium is 2 give reason
Answer:
the valency of an element is its combining capacity that is the number of electrons it requires to lose, gain or share in order to become neutral.
[ An element can become neutral if it completes it's octet. That is if an element has 8 electrons in it'd outermost shell then it is considered neutral ]
The valence of Magnesium is 2 because it requires to lose 2 electrons to become neutral. whereas, the valence of Oxygen is 2 because it needs to gain 2 electrons to become stable.Hence they both have the same valence.
One may say that oxygen's valence is -2 while that of Magnesium is + 2. It's meaning is still the same but "-" sign indicates that oxygen will be gaining electrons in the process of becoming stable.
What happen when:
a. Magnesium Burns in oxygen.
b. Calcium carbonate is heated.
c. Hydrogen reacts with nitrogen at necessary condition.
d. potassium hydroxide reacts with nitric acid.
e. Carbon dioxide is treated with limewater.
Please help me to do this problem.
a. Magnesium Burns in oxygen.
--⟩it produces light bright enough to blind you temporarily.
b. Calcium carbonate is heated.
--⟩ form calcium oxide and evolve carbon dioxide gas.
c. Hydrogen reacts with nitrogen at necessary condition.
----⟩some of the hydrogen and nitrogen will react to form ammonia.
d. potassium hydroxide reacts with nitric acid.
---⟩When potassium reacts with nitric acid then, potassium displace hydrogen from its solution and becomes colorless liquid.
e. Carbon dioxide is treated with limewater.
---⟩to form a white precipitate (appears milky) of calcium carbonate, CaCO 3.
Hope it is helpful to you
Who discovered how gravity affects objects on Earth quizlet?
Answer:
Gravity, Isaac Newton discover
The plasma membrane is made up of a double layer of
Answer: yes
Explanation:
bilayer of lipids, oily substances found in all cells
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?
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
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?
WILL GIVE BRAINLIEST!!!!!!!!!!!!!!!
Answer:
Yes a chemical reaction is taking place.
Explanation:
There is a change in temperature along with bubbling. All signs of a chemical reaction.
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.
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 please i am confused
It is pholem or phloem
Answer:
phloem I believe
Explanation:
dictionary
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
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
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.
Believe it!!
Pls follow me.
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
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)
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.
Learn more: https://brainly.com/question/12047300
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.
Learn more: https://brainly.com/question/17696329
What is the purpose of the lab
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
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
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.
Learn more about law of conservation of mass from the link given below.
https://brainly.com/question/28711001
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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
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Answer:
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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
cuales son los numeros cuanticos con ejemplo
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.
I hope it helps you!
