Answer:
B
Explanation:
Mass number = number of neutrons + number of protons
Atomic number is the number of protons in the nucleus.
58Ni : 58 is the number of neutrons + number of protons
atomic number of Ni is 28. Thus, 58 -28 = 30 neutrons
57Co ; 57 is the number of neutrons + number of protons
number of Co is 27. Thus, 57 – 27 = 30 neutrons
the number of moles in 4.5 x 10^24 atoms of oxegen is
Answer:
The answer is 7.48 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\ [/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{4.5 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 7.47508...[/tex]
We have the final answer as
7.48 molesHope this helps you
Name the gas evolved when Zn reacts with dil.HCI (choose the answer from the following)
1. O2 2. H2 3. CO2 4. Cl2
Answer:
H₂
Explanation:
9A. A sample of hydrogen at 1.56 atm had it's pressure decreased to 0.73
atm producing a new volume of 751 mL. What was its original volume? *
Answer:
351.43mL
Explanation:
To calculate the original volume of hydrogen gas in this question, the Boyle's law equation will be used. Boyle's law equation is:
P1V1 = P2V2
Where; P1 = initial pressure
V1 = initial volume
P2 = final pressure
V2 = final volume
According to this question, the P1= 1.56atm, V1 = ?, P2 = 0.73atm, V2 = 751mL
Hence;
P1V1 = P2V2
1.56 × V1 = 0.73 × 751
1.56 V1 = 548.23
V1 = 548.23/1.56
V1 = 351.43mL
Therefore, the original volume of hydrogen gas is 351.43 mL.
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Type the correct answer in the box. Spell all words correctly.
Stacy finds a gun at a crime scene. Which part of the gun should she never touch?
Stacy knows never to touch the __________
with her hands or any other object so she does not accidentally discharge the weapon.
Answer:
the trigger . it's the trigger
Answer:
It is the handle
Explanation:
I know because I did this test in school
Intensive or Extensive?
The shipping cost of a book(depends on weight)
The number of pages in the first chapter.
The number of pages in a book.
The characterization of the following statements with respect to intensive or extensive is as follows:
The shipping cost of a book(depends on weight): Extensive.The number of pages in the first chapter: Intensive.The number of pages in a book: Intensive. What is Extensive?Extensive may be defined as terminology that illustrates any event or action which is extremely large and significantly found at the outer level of any referring details. For example, the shipping cost of a book (depends on weight) is mentioned outside the cover of the book.
Intensive may also be characterized as a scientific terminology that significantly deals with any object or details which is present inside the content. For example, the number of pages in a book is mentioned inside the book.
Therefore, the characterization of the following statements with respect to intensive or extensive is appropriately described above.
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Highlands are:
A.The tall mountains thrown up by the impact of meteors with the Moon
B.Areas of lava flow
C.Impact sites of meteors on the surface of the Moon
D.The original surface crust of the Moon
How would the particles of a solid, liquid, and gas ALL at room temperature compare? *
A.solid particles have lower average kinetic energy
B.the gas particles are larger than both solid and liquid
C.the pas particles are moving the slowest
D.the spacing of the particles is different, but all have the same average kinetic energy
Plz help
Answer:
A
Explanation:
Solid particles only vibrate, so they have very little kinetic energy.
For B, the size of the particles stay the same, just phase/state changes, so not B.
For C, gas particles move the fastest compared to liquid and solid given the same environment.
For D, they don't have the same kinetic energy because solid particles barely move while gas particles keep moving.
Which of the following is an example of how pictures of a planet's surface can provide evidence about the planet's natural resources?
Answer:
it can show how much green is left. and how climate change is going, and the cloud shows how much oxygen is left in the air.
You will learn in this course that organic compounds have covalent bonds with a significant amount of energy stored in them. This is why we burn fossil fuels to generate energy to heat our homes or drive our cars. Given this information, which of the compounds listed below would you expect to have the most energy is its carbon-carbon bond?
Answer:
See explanation
Explanation:
This question is obviously supposed to be a multiple choice question but the options are missing.
However, the question intends to test the student's knowledge about combustion of fossil fuels. Fossil fuels are mostly composed of hydrocarbons of different chain lengths.
The longer the chain length, the greater the energy released when the compound is burnt since there are more energy stored in its bonds.
Hence, the correct answer to this question will be the option that contains the greatest number of C-C and C-H bonds.
How to separate these pure substance?if it is not possible, please write cannot be separate
Oxgen
Water
Gold
Carbon Dioxide
Carbon
Answer:
Oxgen- cannot be separated
Water - chemical change
Gold - cannot be separated
Carbon Dioxide - chemical change
Carbon - cannot be separated
Explanation:
A pure substance, which can either be an element or a compound, contains only one type of such element or compound. In opposition to a mixture, pure substances cannot be separated by physical means.
- Elements as a pure substance cannot be separated because it contains only one type of atom. However, compounds contain two or more types of atoms, and hence, can only be separated into its individual atoms via chemical means.
In this question, oxygen (O2), Gold (Au) and carbon (C) are all elements and hence cannot be separated. Carbon dioxide (CO2) and water (H2O) are compounds because they contain two different atoms respectively, hence, can be separated into individual atoms.
Question: Give the name for
the following compounds
1. MgF2
2. C2H6
3. Fe203
If an atom has 15 protons and how many electrons will be gained when this atom forms an ion?
Answer:
What are the Answer choices
science 10 workbook
Answer:
for more details are in the pic
25 cm of liquid 'A' and 20 cm of liquid
'B' are mixed at 25°C and the volume of
solution was measured to be 44.8 cm3
then correct reaction is
(A) A Hmix = 0, solution shows
ideal
Answer:
The correct option is;
(B) [tex]\Delta H_{mix} < 0[/tex], solution shows negative deviation
Explanation:
The given parameters are;
The available volume of liquid A = 25 cm³
The available volume of liquid B = 20 cm³
The volume of the solution (mixture) = 44.8 cm³
Therefore, we have;
[tex]\Delta _{mix} V < 0[/tex]
Which is one of the prerequisite for the formation of negative deviation
When a non-ideal solution shows negative deviation according to Raoult's Law, we have;
[tex]\Delta _{mix} H < 0[/tex], we have more heat released due to new molecular interactions.
Whas the the ionic radius of strontium
Answer: 255 pm
Explanation: Hope this helps!
The half life of radon 222 is 3.824 days, how much time must pass of one fourth of a given amount of radon to remain?
Answer:
After 7.648 days, you will see one quarter.
Explanation:
1 → 0.5 → 0.25
Since half life of radon-222 is 3.824 days, you need twice this time to get one quarter at the end.
2 ⋅ 3.824 = 7.648 days.
is CO2 a compound, molecule, or atoms/elements?
Answer:
CO2 is a compound cause there is more then one
The modern synthesis combined the concepts of _______ and evolution.
7)
What is the correct name for the compound, P2O5?
A)
diphosphorus pentoxide
B)
phosphorus pentoxide
6)
diphosphorus oxide
D)
phosphorus oxide
Phosphorus pentoxide is a white solid that has no noticeable smell. This substance has the chemical formula P₄O₁₀. But its name comes from its empirical formula, P₂O₅. Here the correct option is B.
This substance is a white solid with a crystalline structure at room temperature. An acid anhydride made from phosphoric acid is phosphorus pentoxide. Due to its strong hygroscopicity, it is employed as a desiccant and a dehydrating agent.
When in contact with water, phosphorus pentoxide hydrolyzes quickly and violently. This reaction produces a lot of heat. The four polymorphs of this chemical that crystallize are different. Because it is so corrosive, metals must be kept away from it.
Thus the correct option is B.
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A mixture cannot be reversed back to it’s original properties (true or false)
Answer:
False
Explanation:
A mixture is composed of two or more substances that are combined through physical means. It has NOT undergo any changes in its chemical properties. So, even though its appearance change, it can be reverted back.
Answer:
That answer would be false.
Explanation:
Depending on the type of mixture, you can separate it and reverse it back to its original properties through filtration, evaporation, distillation, and chromatography.
Express the difference of 7.69 and 4.0 using the correct number of significant digits:
3.7
3.70
3.6
0
3.69
Answer:
3.7
Explanation:
Significant figures:
All non-zero digits are consider significant figures like 1, 2, 3, 4, 5, 6, 7, 8, 9.
Leading zeros are not consider as a significant figures. e.g. 0.007 in this number only one significant figure present which is 7.
Zero between non zero digits are consider significant such as 1004 consist of four significant figures.
The zeros at the right side such as 4500 are also significant. There are four significant figures are present.
When we add or subtract the values the number of significant figures after decimal in result must be equal to the given measurement having less number of decimal places.
When we multiply or divide the values the number of significant figures must be equal to the less number of significant figures in given value.
Now we will calculate the difference between 7.69 and 4.0.
7.69 - 4.0 = 3.69
In given values 4.0 have less number of decimal places thus result must have only one decimal places. So we would round the result.
3.7
The formula for finding density of a regularly shaped object is LxWxH.
True
False
Its true im pretty sure
It's true
Hope this helped!
what's for the last 1?
Answer:
Explanation:
(i) Which one of these structures A to E represents a noble gas?
Noble gases have completely filled outer most orbital. It means they have 8 valence electrons. Picture D have 8 valence electrons thus it represent noble gas.
(ii) Which two of these structures represent atoms from the same group of the periodic table?
Atoms present in same group having same number of valence electrons.
Picture A and C both have one valence electron thus both are present in same group.
(iii) Which one of these structures represents an atom with an atomic number of 8?
Picture B have total 8 number of electrons it means this atom have atomic number 8. So answer is picture B.
(iv) Which one of these structures forms a stable ion by gaining one electron?
Ions are formed by gaining or losing the electrons. When an atom gain electron anion is formed. There are 7 electron in outer orbital of picture E when it gain one electron outer orbital become completely filled thus form stable ion.
(v) Which one of these structures is in period 3 of the periodic table?
Picture C have 11 electron it means this atom have atomic number 11 which represent sodium. Sodium is present in period 3. Thus answer is picture C.
Write the balanced symbol equation for the electrolysis of aluminium oxide to produce aluminium, and the reduction of iron oxide with carbon to produce iron.
Then use that to calculate the atom economy for each.
Answer:
Electrolysis of Al₂O₃: 4Al³⁺ (s) + 6O²⁺ (g) → 4Al (s) + 3O₂ (g)
Reduction of Elemental Fe: 2Fe₂O₃ (s) + 3C (s) → 4Fe (s) + 3CO₂ (g)
Atom Economy for Electrolysis of Al₂O₃: 52.9227%
Atom Economy for Reduction of Fe₂O₃: 62.8534%
Explanation:
Step 1: Define Compounds
Aluminum Oxide - Al₂O₃
Iron Oxide - Fe₂O₃
Step 2: RxN
Al₂O₃ (s) → Al (s) + O₂ (g)
Fe₂O₃ (s) + C (s) → Fe (s) + CO₂ (g)
Step 3: Balance RxN
2Al₂O₃ (s) → 4Al (s) + 3O₂ (g)
We need the same number of O on both sides (6 is the LCM)We will also need to balance the number of Al on both sides due to the change of O (4 reactant/product)This is ONLY the decomposition reaction for Aluminum oxide, NOT the electrolysis.
2Fe₂O₃ (s) + 3C (s) → 4Fe (s) + 3CO₂ (g)
We need the same number of O on both sides (6 is the LCM)We will also need to balance the number of Fe on both sides due to the change of O (4 reactant/product)We will also need to balance the number of C on both sides due to the change of O (3 reactant/product)This is the final single-replacement reaction for the reduction of Iron Oxide to Iron.
Step 4: Electrolysis of Al₂O₃
We will have to use oxidation-reduction reactions (half-reactions). Let's break up the reaction into it's elements.
Al³⁺ + ? → Al
To make the ion Al³⁺ turn into its neutral atom, we will need to add 3e⁻ to balance the half reactionAl³⁺ + 3e⁻ → Al
O²⁻ → O₂ + ?
Oxygen is a diatomic element, and in it's natural state is bonded to itself. We need to balance the half reaction2O²⁻ → O₂ + ?
We need to figure out how much electrons the ion O²⁻ loses to turn into its neutral atom. We see that we will need to lose 4e⁻2O²⁻ → O₂ + 4e⁻
Our half reactions:
Al³⁺ + 3e⁻ → Al
2O²⁻ → O₂ + 4e⁻
We now need balance the entire half reaction. Our LCM is 124 (Al³⁺ + 3e⁻ → Al) = 4Al³⁺ + 12e⁻ → 4Al
3 (2O²⁻ → O₂ + 4e⁻) = 6O²⁻ → 3O₂ + 12e⁻
Add the 2 half reactions4Al³⁺ + 12e⁻ + 6O²⁺ → 4Al + 3O₂ + 12e⁻
Cancel out spectator ions/e⁻ to get our final half reaction4Al³⁺ (s) + 6O²⁺ (g) → 4Al (s) + 3O₂ (g)
Step 5: Atom Economy
According to GCSE and my own deciphering, your equation for Atom Economy is essentially calculating for something similar to percent yield (but not quite).
[tex]Atom \hspace{3} Economy \hspace{3} = \hspace{3} \frac{Molar \hspace{3} Mass \hspace{3} of \hspace{3} Product}{Molar \hspace{3} Mass \hspace{3} of \hspace{3} All \hspace{3} Reactants} \cdot 100 \%[/tex]
4Al³⁺ (s) + 6O²⁺ (g) → 4Al (s) + 3O₂ (g)Molar Mass of Al - 26.98 g/mol
Molar Mass of O - 16.00 g/mol
Reactants: 4(26.98 g/mol) + 6(16.00 g/mol) = 203.92 g/mol
Products (Al as end product): 4(26.98 g/mol) = 107.92 g/mol
[tex]Atom \hspace{3} Economy \hspace{3} = \hspace{3} \frac{107.92 \hspace{3} g/mol}{203.92 \hspace{3} g/mol} \cdot 100 \%=52.9227 \%[/tex]
2Fe₂O₃ (s) + 3C (s) → 4Fe (s) + 3CO₂ (g)Molar Mass of Fe - 55.85 g/mol
Molar Mass of O - 16.00 g/mol
Molar Mass of C - 12.01 g/mol
Reactants: 4(55.85 g/mol) + 6(16.00 g/mol) + 3(12.01 g/mol) = 355.43 g/mol
Products (Fe as end product): 4(55.85 g/mol) = 223.4 g/mol
[tex]Atom \hspace{3} Economy \hspace{3} = \hspace{3} \frac{223.4 \hspace{3} g/mol}{355.43 \hspace{3} g/mol} \cdot 100 \%=62.8534\%[/tex]
Step 6: Check for significant figures
Since we are not given any values, we don't really need to change any numbers to fit sig fig rules.
A jogger with a mass of 60 kg is moving at 2 m/s. What is the jogger's kinetic energy?
Answer:
Ke = mgv
Explanation:
(60)(9.81)(2) =1177.2 joules persecond or Watts.
1.177 kilowatts
explain the effect of temperature, pressure, volume and concentration reaction rate
When you increase the pressure, the molecules have less space in which they can move. That greater density of molecules increases the number of collisions. When you decrease the pressure, molecules don't hit each other as often and the rate of reaction decreases. Pressure is also related to concentration and volume.
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does breast cancer occur in women? what are the signs and symptoms ?
actually anatomy & physiology own words pls i need it now
Answer:
Breast Cancer occurs in a lot of women.
Explanation:
The following are some symptoms of breast cancer in women.
New lump in the breast or underarm (armpit).
Thickening or swelling of part of the breast.
Irritation or dimpling of breast skin.
Redness or flaky skin in the nipple area or the breast.
Pulling in of the nipple or pain in the nipple area.
Nipple discharge other than breast milk, including blood.
Another thing is that women each year after age 40 are encouraged to get a mamogram.
Answer:
yes breast cancer can occur in both men and women.
Explanation:
some warning signs can be feeling a new lump on or around the breast or in the arm pit area, swollen or redness, also discharge from the nipple can be a sign of breast cancer. Breast pain that doesn't go away can be a sign of breast cancer.
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Select each process that shows a physical change. Select all that apply. Several logs chopped into pieces. Chopping Wood Logs burning as in a campfire. Burning Wood A pot of water on a grate over a burning fire. Heating Water A marshmallow on a stick held above a fire. Roasting Food
Answer:
Chopping wood logsA pot of water o a grate over a burning fireExplanation:
Physical change is easily reversible. Burning/combustion is a chemical process where substances react rapidly with oxygen: this is usually irreversible.
The marshmallow, roasted food and burned wood all undergo combustion and hence are tagged chemical changes.
I hope this helps.
Answer:
Chopping Wood
Heating Water
Explanation:
What is the ratio of aluminum atoms to oxygen atoms in aluminum oxide?
Answer:
Al2 O3 or 2:3
Explanation:
The aluminum oxide consists of two elements, which are oxygen atoms and aluminum atoms, and there are 2 aluminum atoms and 3 oxygen atoms in aluminum oxide. The ratio from aluminum atoms to oxygen atoms is 2:3.
There are two types of chemical compound one is covalent compound and other is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Therefore, the ratio of aluminum atoms to oxygen atoms in aluminum oxide is 2:3.
What is chemical Compound?Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.
An ionic compound is a metal and nonmetal combined compound. Ionic compound are very hard. They have high melting and boiling point because of strong ion bond. The ratio of aluminum atoms to oxygen atoms in aluminum oxide is 2:3. Aluminium oxide is an ionic compound.
Therefore, the ratio of aluminum atoms to oxygen atoms in aluminum oxide is 2:3.
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list 3 examples of pairs of atoms with ionic bonds
Answer:
Na(0.93) & F(3.98)
K(0.82) & Cl(3.16)
Cs(0.79) & Br(2.96)
Explanation: