A fictitious element X is composed of 10.0 percent of the isotope 55 X, 20.0 percent of the
isotope 56 X, and 70.0 percent of the isotope 57 X. Estimate the atomic mass of element X.
Answer:
56.6 g/mol.
Explanation:
Assuming here that we have 100 atoms of each element. The percentage tells us that we have 10 atoms of the 55 isotope, 20 of the 56, and 70 of the 57.
So the total is 10*55 + 20*56 + 70*57 = 5,660. And to get the average, we just divide by the total number of atoms (100).
Atomic mass = 5660/100 = 56.6
a scientist uses 52g of Na2SO4 for a chemical reaction. how many moles of Na atom does the compound contain a) 0.366 b) 0.732 c) 8.422 d)16.845
Answer:
b). 0.732
Explanation:
52g Na₂SO₄ x 1 mol Na₂SO₄ x 2 mol Na
------------------------- -------------------- = 0.732 mol Na
142.04 g Na₂SO₄ 1 mol Na₂SO₄
Atomic Mass Units
Na₂ = 22.99 x 2 = 45.98
S = 32.06
O₄ = 16 x 4 = 64
Na₂SO₄ = 45.98 + 32.06 + 64 = 142.04
There are 2 moles of Na in 1 mole of Na₂SO₄
Someone pls help me I will make you brain
what is the polystyrene?
Answer:
Polystyrene is a versatile plastic used to make a wide variety of consumer products.
Explanation:
Answer:
polystyrene, a hard, stiff, brilliantly transparent synthetic resin produced by the polymerization of styrene. Styrene is obtained by reacting ethylene with benzene in the presence of aluminum chloride to yield ethylbenzene.
Explanation:
in other words its a plastic
Question 8 (2 points)
(02.02 LC)
A mixture contains nuts, drink mix, orange slices, and berries. Which part of this mixture is soluble in water? (2 points)
а
Berries
Ob
Drink mix
Ос
Nuts
Od
Orange slices
Question 9 (2 points)
(02.02 LC)
which of the following dissolve in water? (2 points)
Answer:
B. Drink Mix
Explanation:
Assuming the drink mix is something like Kool-aid, it is soluble in water. The rest are solids that cannot be dissolved in water.
cho các chất sau NaO2,Na,NaOH,Na2SO4,Na2SO3,NaCl,AgCl hãy lập thành dãy chuyển hoá , hoàn thành bằng phương tình phản ứng
Answer:
brainless me plss i help you out
Bromine is an element that often gains an electron to become a negatively charged ion. Potassium is an element that often loses an electron to become a positively charged ion.
Why are bromine and potassium likely to react with one another?
Bromine needs to gain one more electron to have a noble gas configuration or 8 valence electrons, & potassium needs to lose one so they make a transference of electrons in an ionic bond.
What are the functions of ionic bonding?Ionic bonding is a type of chemical bonding that involves the electrostatic attraction between oppositely charged ions, or between two atoms with sharply different electronegativities, and is the primary interaction occurring in ionic compounds.
Ionic bonding results in compounds known as ionic, or electrovalent, compounds, which are best exemplified by the compounds formed between nonmetals and the alkali and alkaline-earth metals.
The charge of a cation or anion is denoted as a superscript after the formula of the ion. A + sign denotes a positive charge resulting from loss of electrons. A - sign denotes a negative charge resulting from gain of electrons.
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Which of the following elements has only one electron in its outermost s orbital?
A. F
B. Al
C.Mg
D.Na
Answer:
D: Na
Explanation:
Hope this helps!
Have a nice day!!
:D
Do the boiling points and melting points of these elements support the claim that elements of the same group have similar physical characteristics?
Answer:
Elements in the same group has different physical properties such as boiling and melting points. However there are trends of their physical properties down the group.
Explanation:
You should look at the perdoic table to for extra help
The boiling points and melting points of the given elements does not support the claim that elements of the same group have similar physical properties.
What are boiling point and melting point?The boiling point of a substance is the temperature at which it changes from liquid state to gaseous state. Melting point is the temperature at which the substance changes from solid to liquid state.
Elements in the same group shows similar physical and chemical properties. But from the boiling and melting point we cant say that they are in the same group.
Elements in a group shows a trend in boiling point and melting point but cannot be distinguished with this from other groups.
Hence, boiling point and melting point of the elements do no support for the similar properties in a group.
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Your question is incomplete, but most probably your full question was,
Do the boiling points and melting points of these elements support the claim that elements of the same group have similar physical characteristics? (image uploaded)
The mass number is equal to the number of blank in the nucleus of the atom
Answer:
c
Explanation:
what is the wavelength of microwaves if the frequency is 2.45x 10^9 HZ?
Wavelength = Speed of Light ÷ Frequency
= (2.99 × 10⁸ m/s) ÷ ( 2.45 × 10⁹ /s)
= 1.22 × 10⁻¹ m
The wavelength of a light of frequency 2.45 × 10⁹ /s is 1.22 × 10⁻¹ m.
Notes:
Hz ≡ /s
Electrons are transferred from one atom to another.
Options:
Ionic Bond or Covalent Bond?
Answer:
ionic
Explanation:
ionic transfer of e^- ions formed (charges)
ionic=non-metal+ metal
ex: F+Ca
covalent sharing e^- no true charges
covalent= non-metal+ non-metal
ex: F+P
( my notes)
what term is used to describe alkaline hydrolysis of fats and oils
Answer:
Saponification
Explanation:
When treated with a base such as NaOH, the ester is transformed back to alcohol and the sodium salt of carboxylic acid. Saponification is the name given to the reaction since it is utilized in the production of soap.
What volume will 75 g of O2 occupy at STP?
p = latm
t = 273.15K
R= 0.08206 L atm mol K
75.0g02
16.00 (O₂) = 4.6875mol mol
9
Ideal gas law: PV = nRT, solve for volume: V = nRT P
V =
4.6875mol 0.08206 L-atm mol. K · 273.15K
V = 105L
latm
LL < 5 6 7 8 9 10 11 7 12 How many atoms are in O2? O 1 O2 3 4
Answer:
2
Explanation:
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Water quality tests show the presence of a single heavy metal in the drinking water pulled from a local river. Residents are suffering from numerous stomach ailments and are showing signs of long-term kidney damage. The residents of the next town, down river from the first town, seem to be unaffected. Water quality tests in the river by the second town show two types of heavy metals at acceptable legal limits in the water. One of the metals is the same as the one in the first town. What can scientists infer about the possible reason for the illnesses appearing in the first town but not the second?
One metal causes an acute effect, compared to the other.
One metal causes a chronic effect, compared to the other.
The heavy metals have a synergistic relationship when combined.
The heavy metals have an antagonistic relationship when combined.
Answer:
One metal causes a chronic effect, compared to the other
Explanation:
because the question only said ONE is the same, didn't they? so that would mean that not all the metals are the same for both towns
Each of these Ionic Compounds are named INCORRECTLY. 1. Find and describe the mistake 2. Correctly name the compound. CaCl2 - Calcium Chlorine CuS - Copper Sulfide Li3P - Trilithium Phosphide CuBr - Copper(II) Bromide NaOH - Sodium Hydrogen Oxide
Explanation:
The nomenclature of ionic compounds is given by:
1. Positive is written first. And if the metal atom has various oxidation states then its oxidation state is to be mentioned in brackets with help of roman numbers
2. The negative ion is written next and a suffix is added at the end of the negative ion. The suffix written is '-ide'.
1.) : Calcium chloride (Correct)
In the given compound, calcium has oxidation state of +2 and chlorine has oxidation state of -1.The name is correct.
2.) : Copper (II) oxide (Incorrect)
In the given compound,copper has the oxidation state of +1 and oxygen has oxidation state of -2.So ,the correct name will be Copper (I) oxide.
3.) : Lead (II) sulfide (Incorrect)
In the given compound, lead has the oxidation state of +4 and sulfur has oxidation state of -2. So ,the correct name will be Lead (IV) sulfide.
how many molecules of water, h2o, are present in 75.0 g of h2o?
Answer:
150 molecules of oxygen
Explanation:
What is igneous rock?
Answer: A) Rock formed by...magma or lava
Explanation:
As the question says, igneous rocks are formed from the cooling and solidification of magma or lava.
just a bit of visual aid thanks to Thoughtco.
Answer:
It is the first one - Rock formed by the cooling and solidification of hot liquid magma or lava.
Explanation:
Two different medical students made models to show their ideas about the molecules that should be in the functioning cells of a healthy body. Using what you have figured out from reading and investigating so far, evaluate the models by answering the questions following the models.
Are these models accurate? choose one)
Medical Student A’s model is accurate.
Medical Student B’s model is accurate.
Both models are accurate.
Neither model is accurate.
Answer:
A
Explanation:
it's a because model is like the same thing as walking on a Runway but it's like a model in the medical field
polonium has a large, unstable nucleus. through which process is it most likely to become stable?
Answer:
alpha decay
Explanation:
an unstable element is radioactive in nature.
Polonium is a chemical element with a large, unstable nucleus.
the most stable isotope of Polonium is Polonium-209, which typically undergoes an alpha decay to form lead-205 and the emission of an alpha particle.
1. Polonium has a large, unstable nucleus. Through which process is it most likely to become stable?
alpha decay
2. Which type of energy does alpha decay generate?
kinetic
3. Use the equation to answer the question.
14 6C→14 7N+ 0−1e
Which type of radioactive decay does the equation model?
beta-minus decay
4. How does the nucleus change in beta-plus decay?
The mass number remains the same, and the atomic number decreases by one
5. An unstable nucleus undergoes gamma decay. How does the nucleus change?
It becomes more stable by repositioning its particles
Explanation: I did the test
All mater has ___ and takes up ___
Matter is anything that has mass and takes up space.
hope this helps <3
Calcium carbonate decomposes into calcium oxide and carbon dioxide when heated. Calculate the mass of carbon dioxide released when 300 g of calcium carbonate is heated.
Write a Balanced Equation for the decomposition
CaCO₃ → CaO + CO₂
Find Moles of CO₂ Produced
Since the mole ratio of CaCO₃ to CO₂ is 1 to 1,
the moles of CaCO₃ = moles of CO₂
moles of CaCO₃ = mass ÷ molar mass
= 300 g ÷ 100.087 g/mol
= 2.997 moles
∴ moles of CO₂ = 2.997 moles
Determine Mass of CO₂
Mass = moles × molar mass
= 2.997 mol × 44.01 g/mol
= 131.9 g
∴ when 300 g of calcium carbonate is decomposed, it produces 131.9 g of carbon dioxide.
The energy an object has due to its movement or position is called
Answer:
Potential energy
Explanation:
When an object is moving its called Potential energy.
When an object is not moving it is called kinetic energy.
Why are plastics known as synthetic materials?
Answer:
It is the length of these chains, and the patterns in which they are arrayed, that make polymers strong, lightweight, and flexible.
Explanation:
Synthetic polymers are made up of long chains of atoms, arranged in repeating units, often much longer than those found in nature. It is the length of these chains, and the patterns in which they are arrayed, that make polymers strong, lightweight, and flexible. In other words, it's what makes them so plastic.
how many atoms of neon are present in 1.30 moles of neon?
Answer:
7.83 x 10^23 atoms
Explanation:
For the following element, predict the most likely oxidation number (charge) for its corresponding ion.
Phosphorus
A. P+1
B. P+3
C. P-1
D. P-3
The most likely ion of Phosphorous is P³⁻ (group 15) since gaining three electrons is the most energetically favorable way for it to follow the octet rule.
Because the charge on ions is equivalent to their oxidation state, then -3 is the most likely oxidation number of Phosphorous.
2. If Ben ran for 15 minutes and went 120 meters, how fast did he run?
Answer:
8m/min
Explanation:
120 m / 15 min = 8 meters per min
What kind of interaction
(attraction/repulsion) will happen
between the core electrons and the
valence electrons?
Elements in which the d-sublevel is being filled have the properties of
Answer:
Elements in which the d-sublevel is being filled have the properties of metals
Elements in which the d-sublevel is being filled have the properties of;
transition metals.
In quantum theory the sublevel is an energy level. Now, the d-sublevel in atomic configuration has 5 orbitals and as such can contain a maximum of 10 electrons.
Now, this d-sublevel is used primarily by elements called "transition elements" as they are also called d-block elements.
However, these transition elements are also called transition metals because all the transition elements possess properties of metals generally.
In conclusion, elements in which the d-sublevel is being filled have the properties of transition metals.
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