Answer:
radioactive decay
Explanation:
How many atoms are in 25.00 g of B.
1.393 x 10^24 atoms of B
1.333 x 10^23 atoms of B
2.16 x 10^26 atoms of B
2.17 x 10^24 atoms of B
Answer:
[tex]\boxed {\boxed {\sf 1.393 *10^{24} \ atoms \ B}}[/tex]
Explanation:
1. Convert Grams to Moles
Use the molar mass (found on the Periodic Table) to convert from grams to moles.
Boron (B): 10.81 g/molUse this value as a ratio.
[tex]\frac {10.81 \ g \ B }{1 \ mol \ B}[/tex]
Multiply by the given number of grams.
[tex]25.00 \ g \ B *\frac {10.81 \ g \ B }{1 \ mol \ B}[/tex]
Flip the ratio so the grams of boron cancel out.
[tex]25.00 \ g \ B *\frac {1 \ mol \ B }{10.81 \ g \ B}[/tex]
[tex]25.00 *\frac {1 \ mol \ B }{10.81 }[/tex]
[tex]\frac {25.00 \ mol \ B }{10.81 }=2.312673451 \ mol \ B[/tex]
2. Convert Moles to Atoms
We use Avogadro's Number, 6.02*10²³: the number of particles (atoms, molecules, etc.) in 1 mole of a substance. In this case, the particles are atoms of boron.
[tex]\frac {6.02*10^{23} \ atoms \ B} {1 \ mol \ B}[/tex]
Multiply by the number of moles we calculated.
[tex]2.312673451 \ mol \ B *\frac {6.02*10^{23} \ atoms \ B} {1 \ mol \ B}[/tex]
The moles of boron cancel.
[tex]2.312673451 *\frac {6.02*10^{23} \ atoms \ B} {1 }[/tex]
[tex]2.312673451 *6.02*10^{23} \ atoms \ B} =1.39269195*10^{24} \ atoms \ B[/tex]
The original value of grams has 4 significant figures, so our answer should have the same. For the number we calculated, that is the thousandth place.
[tex]1.392\underline69195*10^{24} \ atoms \ B[/tex]
The 6 tells us to round the 2 to a 3.
[tex]1.393 *10^{24} \ atoms \ B[/tex]
25.00 grams of boron is equal to 1.393*10²⁴ atoms.
help me out with my homework
Answer:
3) The salivary glands present in the mouth produces saliva
Types of chemical bonds & names
Answer:
There are three primary types of bonding: ionic, covalent, and metallic. Definition: An ionic bond is formed when valence electrons are transferred from one atom to the other to complete the outer electron shell.
Explanation:
¿Por qué crees que es importante conocer nuestra condición económica antes de practicar actividades físicas regularmente?
Answer:
el ejercicio físico ayuda a gente a perder peso y reduce el riesgo de desarrollar algunas enfermedades. el ejercicio físico regular el reducen los riesgos de ciertas enfermedades como obesidad, diabetes tipo 2 e hipertensión el ejercicio físico puede ayudar a mantener el cuerpo en un peso saludable pero a veces algunos tienen enfermedades al corazón o asma y les afecta a ser demasiado práctica esa actividad
In the reaction shown above , the?
Answer:
I think option (d) is right answer
M C Q s
1) The most reactive metal is :
a) Na b) Cu c) Fe d) Ca
Answer:
A
Explanation:
A, Na b/c The elements toward the bottom left corner of the periodic table are the metals that are the most active in the sense of being the most reactive. Lithium, sodium, and potassium all react with water,
A ball is sitting at the top of a ramp. As the ball rolls down the ramp, the potential energy of the ball decreases. What happens to the potential energy as the ball moves
Answer:
it is converted to kinetic energy
Pb(NO3)2 (aq) + 2 NaI (aq) --> PbI2 (s) + 2 NaNO3 (aq)
Starting with with 50.0 grams of Pb(NO3)2 and 30.0 grams of NaI:
A. What is the limiting reagent?
B. How many grams of the excess reactant remains?
C. How many grams of each product is formed?
D. If 12 grams of NaNO3 actually formed in the reaction, what is the percent yield of this reaction?
Answer:
Explanation:
Moles of Pb(NO3)2 = mass/molecular mass
= 50.0 grams/(207.20*1 + 14.01*2 + 16*6)
= 50.0 grams/331.22
= 0.15 moles
Moles of NaI
= 30/(22.99+126.9)
= 30/149.89
= 0.2 Moles
A. NaI is less 2x Pb(NO3)2 so NaI is the limiting reagent.
B. The ratio is 1 to 2 so there is 0.15 - 0.2/2 = 0.05 mole
or 16.78 grams of Pb(NO3)2 left.
C. As NaI is limiting, only 0.2 Moles of NaNO3 is formed.
Mass = Moles * Molecular Mass
Molecular Mass of NaNO3 can be calculated as:
Na - 22.99
N - 14.01
O - 3(16) = 48
23+14+48 = 85gram / mole
Thus, Mass = 0.2*85 = 17 gram of NaNO3
Mass is conserved in a chemical reaction.
Mass of PbI2 can be calculated as:
50+30-16.78-17
= 46.3 gram of PbI2
Mass =
12.75
Thus, 12.75g of Sodium Nitrate can be formed
Answer:
Explanation:
Pb(NO3)2 (aq) + 2 NaI (aq) --> PbI2 (s) + 2 NaNO3 (aq)
MM for each compound -
Pb(NO3): 207 + 14x2 + 16x3x2 = 331
PI2: 207 + 127x2 = 461
NaI: 23 + 127 = 150
NaNO3: 23 + 14 + 16x3 = 85
Moles of Pb(NO3)2 = 50/331 = 0.15
Moles of NaI = 30/150 = 0.2
Ratio of moles is 1:2
So NaI is limiting
Limited to 0.2/2 = 0.1 mole of Pb(NO3)2
Excess = 0.15 - 0.1 = 0.05 mole
Mass remains = 0.05x331 = 16.55 grams
Moles of NaNO3 formed = Moles of NaI reacted = 0.2
Mass = 0.2x85 = 17 grams
Moles of PbI2 formed = Moles of Pb(NO3)2 reacted = 0.1
Mass = 0.1x461 = 46.1 grams
If 12 grams of NaNO3 actually formed in the reaction,
percent yield = 12/17x100% = 70.6%
Science help due by 11:59 What is gravity like on other planets
compared to Earth?
Explanation:
Mercury 0.377 g
Venus 0.905 g
Earth 1 g (midlatitudes)
Moon 0 .165 7 g (average)
What happens to the end of the O2 molecule that is closest to the positive end of the H2O molecule?
Hydrogen bond will be formed when the end of the O₂ molecule that is
closest to the positive end of the H₂O molecule.
What is Hydrogen bond?These are referred to as electrostatic force which occurs between
Hydrogen atom and other electronegative atom bearing a lone pair of
electrons.
Oxygen is electronegative and has lone pair of electrons which is why the
bond formed will be Hydrogen bond.
Read more about Hydrogen bond here https://brainly.com/question/12798212
someone help me with this problem pls
Answer:
magnetic field
Explanation:
P waves are classified as
O Surface Waves
Or
O. Body waves
Help plzzzz
Answer:
Surface
Explanation:
Which of the gas laws takes into account the forces of attraction between molecules based on the characteristics of the gas? *
Ideal Gas Law
Boyle's Law
Charles's Law
Van der Waals's Law
how does this data provide evidence for base pairing in dna
Answer:
There are chemical cross-links between the two strands in DNA, formed by pairs of bases. They always pair up in a particular way, called complementary base pairing: thymine pairs with adenine (T–A) guanine pairs with cytosine (G–C)
Explanation:
Hope it helps u
FOLLOW MY ACCOUNT PLS PLS
Which subatomic particle orbits the nucleus?
O the electron
o the neutron
O the proton
it’s electron btw
Answer: Subatomic particle which orbits the nucleus is electron.
Explanation:
Every atom contains three sub-atomic particles. These are protons, neutrons and electrons.
Protons contain a positive charge, neutrons have no charge and electrons have a negative charge.
Both protons and neutrons reside inside the nucleus of the atom whereas electrons reside outside the nucleus of atom and revolve around the nucleus.
Therefore, it is concluded that subatomic particle which orbits the nucleus is electron.
1. Who was the first person to create a periodic table? When?
2. What is the modern periodic table?
3. Compare and contrast the periods and groups of the modern periodic table.
4. In the modern periodic table (found in the back of your agenda), find the element named lead (Pb). How many protons do atoms of lead have? To which class of elements does lead belong?
5. Most of the elements on the periodic table belong to what class of elements.
6. Which groups of the modern periodic table contain elements that are classified as metalloids?
Answer:
Mendeleev discovered the periodic table (or Periodic System, as he called it) while attempting to organise the elements in February of 1869.
Explanation:
Mendeleev discovered the periodic table (or Periodic System, as he called it) while attempting to the elements in February of 1869. also I made a enderBender of our pfp!
Which element, when combined with phosphorus, would form an ionic compound?
A) Carbon.
B)Oxygen.
C)Magnesium.
D)Boron.
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 correct option is option C.
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.
Since phosphorus is a nonmetal, we need a metal. Out of given option the only element that is metal is Magnesium while others are non metal.
Therefore, the correct option is option C.
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what do you get if oceanic plates are moving away from one another
Answer:
Explanation:
When two plates are moving away from each other, they are called a divergent plate boundary.Along these boundaries, magma rises from deep within the Earth and erupts to form new crust on the lithosphere.
Helped by none other than the #Queen herself!
How is matter conserved through cellular respiration
Answer:
In cellular respiration, complex molecules containing carbon react with oxygen to produce carbon dioxide and other materials. ... Matter is conserved during cellular respiration because atoms are conserved in physical and chemical processes
Explanation:
I hope this helps
P4 +6Br2 --> 4PBr3
What is the ratio of the moles of P4 consumed to moles of PBr3 produced?
Answer:
1 mole of P₄ consumed:4 moles of PBr₃ produced
Explanation:
Look at the coefficients in the balanced chemical equation to determine the ratios. For every 1 mole of P₄ consumed (P₄ has a coefficient of 1), 4 moles of PBr₃ would be produced (PBr₃ has a coefficient of 4).
Answer:
[tex]\boxed {\boxed {\sf 1 \ mole \ P_4 consumed \ to \ 4 \ moles \ PBr_3 \ produced}}[/tex]
Explanation:
To find the mole ratio, we must use the coefficients.
[tex]P_4+6Br_2 \rightarrow 4PBr_3[/tex]
This equation is balanced (4 atoms of P and 12 atoms of Br on both sides), so we can go straight to the coefficients.
P₄ doesn't have a coefficient, so 1 is implied Br₂ has a coefficient of 6PBr₃ has a coefficient of 4So according to the coefficients above, for every 1 mole of P₄ that is consumed, 4 moles of PBr₃ are produced. Therefore, the ratio is 1 mole P₄ to 4 moles of PBr₃.
what are the list of catalysts that can be used for hydrogenation of nitrobenzene???
Answer:
The multiring aromatic hydrocarbons in the coal liquid were hydrogenated to give saturated molecules that contained only one aromatic ring. Of the several organic bases investigated, potassium bis(trimethylsilyl)amide was found to be the most effective catalyst.
Explanation:
If you want to make 174 grams of NiFz, how many moles of HF will you need, using
the following balanced chemical equation? Ni + 2 HF - NiF2 + H2
Answer:
3.6mol
Explanation:
The balanced chemical equation of this reaction is given as follows:
Ni + 2HF → NiF2 + H2
Based on the above equation, 2 moles of HF will react to produce 1 mole of NiF2.
According to this question, to make 174 grams of NiF2, we find the number of moles of HF required. However, we first convert the mass value of NiF2 to mole value using;
mole = mass/molar mass
Molar mass of NiF2 = 58.7 + 19(2)
= 58.7 + 38
= 96.7g/mol
mole = 174/96.7
mole = 1.799mol of NiF2
Hence, if 2 moles of HF will react to produce 1 mole of NiF2.
- 1.799mol of NiF2 will require (1.799 × 2) = 3.598
= 3.6mol of HF.
can someone do this for me i wasent there when we learned it
5 *
1 point
Two elements are in the same group of the Periodic Table.
Which property will be the same for both elements?
A the charge on their ions
B their electronic structure
C their melting point
D their reactivity with water or acids
Answer:
A. the charge on their ions
Explanation:
Elements are grouped into the same group in the periodic table if they have the same valence electrons. However, the number of valence electrons an element has, determines the number of charges it can possess.
According to this question, two elements in the same group of the periodic table will have the same charge on their ions because they both have the same number of valence electrons.
how many moles of CO2 molecules are in 120 g of CO2
Answer:
The answer is 44.0095.
Explanation:
1 grams CO2 is equal to 0.022722366761722 mole. so take that and multiply by 120 and you get 44.0095.
120 g of CO₂ correspond to 2.73 moles of CO₂.
First, we need to determine the molar mass (M) of CO₂ by adding the masses of its elements in 1 mole of CO₂.
[tex]M(CO_2) = M(C) + 2M(O) = 12.01 g/mol + 2(16.00 g/mol) = 44.01 g/mol[/tex]
We have a mass (m) of 120 g of CO₂. We can calculate the number of moles (n) using the following expression.
[tex]n = \frac{m}{M} = \frac{120 g }{44.01 g/mol} = 2.73 mol[/tex]
120 g of CO₂ correspond to 2.73 moles of CO₂.
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What is the name of the element represented in the model?
O A. Beryllium
B. Boron
O C. Oxygen
O D. Flourine
Answer:
Your answer is B
Boron
Good luck
Explanation:
If an electrical current can run though a solution, it is said to contain what?
Answer:
electrolytes
Explanation:
If an electrical current can run though a solution, it is said to contain ions and the solution in which ions are present is called as electrolytes.
What are ions?
An ion is defined as an atom or a molecule which has a net electrical charge. There are 2 types of ions :1) cation 2) anion . The cation is the positively charged ion and anion is the negatively charged ion . As they are oppositely charged they attract each resulting in the formation of ionic bond.
Ions consisting of single atom are mono-atomic ions while which consists of two or more ions are called as poly-atomic ions . They are created by chemical interactions . They are very reactive in their gaseous state and rapidly react with oppositely charged ions resulting in neutral molecules.
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Summary of exothermic and endothermic
Please help with the chart 10 questions
1. Which type of energy is representing by the moving of objects?
2. What type of energy is stored?
3. Explain the lot of conversation of energy?
4. A metal spoon and a wooden spoon are placed in a pot of boiling water. What property of the metal spoon causes it to become hotter than the wooden spoon and why?
5. The thing we measure when we want to determine the average kinetic energy of random motion is the particles of a substance is ___________.
6. The __________ is the energy needed to raise the temperature of a substance by 1°C.
7. A(n) ________ reaction is one where the products have lower energy than the reactants.
8. __________ reaction requires energy in order to take place.
9. The __________ is used to describe how much energy is produced or used during a chemical change.
4. What coefficients do you need to balance the following equation?
CH4 + O2 + CO2 + H2O
O 1, 2, 1, 2
O 2, 1, 1, 1
O 1, 1, 1, 1
O 2, 1, 2, 2
Answer:
option first is the right answer
If 1.00 L of gas at 1.00 atm of pressure is compressed to a volume of 0.473 L, what is the new pressure of the gas?
Answer:
2.11
Explanation:
1/0.473 = 2.11
