Answer:
protons and nuetrons
Explanation: protons have a positive charge and nuetrons which have no charge together the make up the middle of an nuclues in a atom. i may be incorrect please tell me if i am
An element has a half-life of 5.0 days. How many days would
pass before only 1/8th of the original amount of a sample of this
element remained?
Answer:
15 days
Explanation:
Given half-life = 5 days => k = 0.693/half-life = 0.693/5 days⁻¹
A = A₀e^-k·t => t = ln(A/A₀) / -k = ln(1/8) / -0.1386 days⁻¹ = 15 days
The element with half life of 5 days have the decay constant of 0.1386 dy⁻¹ will take 15 days to decay to its 1/8th part of initial amount.
What is half life ?Heavy unstable radioactive isotopes undergo nuclear decay by the emission of charged particles. Nuclear decay is a first order reaction.
Thus, the decay constant k = 1/t ln W0/Wt
where t is the time of decay, W0 be the initial amount and Wt be the amount after time t.
The half life of the element = 5 days.
decay constant = 0.693/t1/2
k = 0.693/5 days = 0.1386 days⁻¹.
The time taken to decay to 1/8th of its original amount is calculated as follows:
t = 1/k ln Wo/(Wo/8 )
= ln 8/0.1386 days⁻¹
= 15 days.
Therefore, the days before the element decay to its 1/8th of original amount is 15 days.
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Calculate the amount of grams of water that was used when 5525J of energy was used to boil this amount of water.
Answer:
2.445 g
Explanation:
Step 1: Given and required data
Energy in the form of heat required to boil the water (Q): 5525 JLatent heat of vaporization of water (∆H°vap): 2260 J/gMass of water (m): ?Step 2: Calculate the mass of water
We will use the following expression.
Q = ∆H°vap × m
m = Q / ∆H°vap
m = 5525 J / (2260 J/g)
m = 2.445 g
How many grams of NO2 are needed to form 88.0 g of HNO3?
Answer:
64.4g
Explanation:
The chemical reaction that will produce HNO₃ from NO₂ is given below:
3NO₂ + H₂O → 2HNO₃ + NO
Given;
Mass of HNO₃ = 88g
Now;
To solve this problem, find the number of moles of HNO₃;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of HNO₃ = 1 + 14 + 3(16) = 63g/mol
Number of moles = [tex]\frac{88}{63}[/tex] = 1.40mol
From the balanced reaction;
2 mole of HNO₃ is produced from 3 mole of NO₂
1.4 mole of HNO₃ will be produced from [tex]\frac{1.4 x 3} {2}[/tex] = 2.1mole of NO₂
Mass of NO₂ = number of moles x molar mass
Molar mass of NO₂ = 14 + 2(16) = 46g/mol
Mass of NO₂ = 1.4 x 46 = 64.4g
Object A has a molar heat of 31.2 J/mole∙°C and object B molar heat is 11.2 J/mole∙°C. Which object will heat up faster if they have the same mass and equal amount of heat is applied? Explain why.
Answer:
Substance B
Explanation:
Molar heat of A = 31.2J/mole.°C
Molar heat of B = 11.2 J/mole∙°C.
The molar heat of a substance is the amount of heat that must be added to a mole of a substance to raise the temperature by 1°C.
Substance B will heat up faster compared to A. It has a smaller molar heat compared to A. This suggests that it will require lesser heat to raise its temperature by 1°C.
You added 20 g of NaCl to 100g of water. What is the percent by mass of the solute? (Hint: You have not been given the total mass of the solution. This must be calculated
We are given:
Mass of solvent (water) = 100 grams
Mass of solute (NaCl) = 20 grams
Mass of the Solution:
Mass of Solution = Mass of Solute + mass of Solvent
100 + 20 = 120 grams
Mass Percent of NaCl:
We know that
mass percent of NaCl = (Mass of NaCl / Mass of Solution) * 100
replacing the variables
Mass% of NaCl = (20 / 120)*100
Mass% of NaCl = 100 / 6
Mass% of NaCl = 16.67%
1. What type of battery was made by alternating layers of silver, zinc and blotting paper soaked in salt?
O voltaic piles
O lead acid batteries
O wet cell batteries
O dry cell batteries
Right answer gets a Brainly!
Answer:
voltaic piles
Explanation:
:3
Answer:
Ik someone already answered it correctly, but it is voltaic piles.
Explanation:
QUESTION 5
What is a mixture?
O Contains one kind of particle and they DO NOT keep thier own identity and properties.
O Contains one kind of particle.
O Contains MORE than one kind of particle and they keep their own identity and properties.
O Contains MORE than one kind of particle and they DO NOT keep their own identity and properties.
Answer:
C
Explanation:
Cccccccccccccccccccc
Answer:
The third option.O contains more than one kind of particles anddd they keep their own identify and properties because the definition of mixture is a material made up of 2 or more different substances which are physically combined and identities are retained
What may form when magma comes to the surface?
Answer
When magma reaches the surface it is called lava. After lava has cooled it forms solid rock.
Answer:
Volcano
Explanation:
when magma reaches the surface it cools and then magma will start coming out over and over and over again. Then we have a volcano. hopemthis helps
pretty please help me (:
Okay I need an explanation from YOU. when is this due? If it’s last minute, why didn’t you do it when you had time? This is very irresponsible, unless you have a personal reason. Please quit commenting on others just for the points. I helped you with one, because I thought it was just one question you needed help with. No one is going to finish this for you. I’m sorry but it’s the truth, everyone here needs help. No one is here TO help. So please be cooperative and try to learn. Of course, I’m sorry if it is for a very personal reason as it happens to everyone where you need the work ASAP because of a reason. Hopefully, it’s not because you were lazy. Appreciate your education as not many people in the world have it.
How did Henry Moseley affect the development of the periodic table?
Answer: "In 1913 he used self-built equipment to prove that every element's identity is uniquely determined by the number of protons it has."
Explanation: If you are using this in an essay, use your own words when you use this. I got this from a website. But I hope it helps!
A tea kettle on a hot burner. Point A is steam coming from the spout. Point B is the heat source. Use the drop-down menu to choose the type of thermal energy transfer shown at each point in the image. A: B:
Answer:
A : convection
B : conduction
Explanation:
Answer:
A. Convection
B. Conduction
Explanation:
C + ZnO ➡️ Zn + CO2
How many moles of zinc will be produced when 0.13 moles ZnO react?
Answer:
0.12 moles of Zn will produced
Explanation:
Given data:
Number of moles of zinc produced = ?
Number of moles of ZnO react = 0.12 mol
Solution:
Chemical equation:
C + 2ZnO → 2Zn + CO₂
Now we will compare the moles of Zn with zinc oxide.
ZnO : Zn
1 : 2
0.12 : 0.12
0.12 moles of Zn will produced.
A 50.0 mL sample of HCl required 25.81 mL of 0.1250 M KOH for neutralization. What is the molarity of the acid?
Answer:
0.065M
Explanation:
The reaction expression is given as:
HCl + KOH → KCl + H₂O
Given parameters:
Volume of KOH = 25.81mL = 0.02581L
Molarity of KOH = 0.125M
Volume of HCl = 50mL = 0.05L
Unknown:
Molarity of the acid = ?
Solution:
To find the molarity of the acid, HCl, let us use the mole concept.
First, find the number of moles of the base, KOH;
Number of moles of KOH = molarity of KOH x volume of KOH
Number of moles of KOH = 0.125 x 0.0258 = 0.003225mol
From the balanced reaction equation:
1 mole of KOH reacted with 1 mole of HCl
0.003225mol of KOH will react with 0.003255mole of HCl
Molarity of HCl = [tex]\frac{number of moles of HCl}{Volume of HCl}[/tex]
Molarity of HCl = [tex]\frac{0.003255}{0.05}[/tex] = 0.065M
How often waves repeat is called their
Answer:
Wave Frequency
A 10.00 mL sample of a 1.07 M solution of potassium hydrogen phthalate (KHP, formula mass = 204.22 g/mol) is diluted to 250.0 mL. What is the molarity of the final solution?
Answer:
[KHP] = 0.0428M
Explanation:
2 methods to calculate concentration after dilution
1. Use dilution equation
Molarity of concentrate (M₁) x Volume of Concentrate (V₁)
= Molarity of dilute (M₂) x Volume of dilute (V₂)
M₁ x V₁ = M₂ x V₂ => M₂ = M₁ x V₁ / V₂ = (1.07M)(10ml)/(250ml) = 0.0428M
2. Concentration Equation
moles KHPh = Molarity (M) x Volume (V) = 1.07M x 0.010L =0.0107 moles KHP
Concentration KHP = moles solute / volume of solution in Liters
= 0.0107 moles KHP / 0.25L = 0.0428M
The molarity of 10.00 mL sample of a 1.07 M solution of potassium hydrogen phthalate diluted to 250.0mL is 0.0428M.
HOW TO CALCULATE MOLARITY:
The molarity of a diluted solution can be calculated by using the following formula:C1V1 = C2V2
Where;
C1 = initial concentration of solutionC2 = final concentration of solutionV1 = initial volume of solutionV2 = final volume of solutionAccording to this question,
C1 = 1.07MC2 = ?V1 = 10.0mLV2 = 250mL1.07 × 10 = C2 × 25010.7 = 250C2C2 = 10.7 ÷ 250C2 = 0.0428MTherefore, the molarity of 10.00 mL sample of a 1.07 M solution of potassium hydrogen phthalate diluted to 250.0mL is 0.0428M.Learn more about how to calculate molarity of a solution at: https://brainly.com/question/13386686?referrer=searchResults
A rectangular solid has the following measurements 6 cm, 10 cm, and 5 cm. what is the volume of the solid?
A student masses a green crystal sample and records 1.253 grams. He then dissolves the green crystal in water and does a titration, and calculates that his sample has 7.35x10-3 moles of C2O4-2.
What is the percent of C2O4-2 in the sample?
a. not enough information is given
b. 51.63%
c. 129%
d. 0.5866%
e. 20.62%
Answer:
b. 51.63%
Explanation:
Step 1: Given data
Mass of the sample: 1.253 gMoles of oxalate (C₂O₄²⁻): 7.35 × 10⁻³ molStep 2: Calculate the mass corresponding to 7.35 × 10⁻³ moles of oxalate
The molar mass of C₂O₄²⁻ is 88.02 g/mol.
7.35 × 10⁻³ mol × 88.02 g/mol = 0.647 g
Step 3: Calculate the mass percent of oxalate in the sample
% w/w = mass of oxalate / mass of the sample × 100%
% w/w = 0.647 g / 1.253 g × 100%
% w/w = 51.63%
During the process of diluting a solution, ________.
a. water is removed from the concentrated solution
b. the amount of solvent does not change
c. the amount of solute does not change
d. the volume of the solution does not change
e. there is more solute in the concentrated solution
Write the balanced equation for the reaction that occurs when aluminum bromide is mixed with potassium sulfate forming potassium bromide and aluminum sulfate
Answer:
2AlBr₃ + 3K₂SO₄ → 6KBr + Al₂(SO₄)₃
Explanation:
Given species;
Reactants
Aluminum bromide = AlBr₃
Potassium sulfate = K₂SO₄
Products
Potassium bromide = KBr
Aluminum sulfate = Al₂(SO₄)₃
So, the reaction equation is given as:
AlBr₃ + K₂SO₄ → KBr + Al₂(SO₄)₃
To balance this chemical equation, let us an algebraic approach;
aAlBr₃ + bK₂SO₄ → cKBr + dAl₂(SO₄)₃
Conserving Al;
a = 2d
Conserving Br;
3a = c
Conserving K;
2b = c
Conserving S;
b = 3d
Conserving O;
4b = 12d
if a = 1;
c = 3
b = [tex]\frac{3}{2}[/tex]
d = [tex]\frac{1}{2}[/tex]
Now, multiply through by 2;
a = 2, b = 3, c = 6 and d = 1
2AlBr₃ + 3K₂SO₄ → 6KBr + Al₂(SO₄)₃
can you help me please
Answer:
N- 7 protons, 14 mass number
Ca- 20 protons, 20 neutrons, 20 electrons
I- 53 protons, 127 mass number
Cr- Cr, 12 neutrons
Br- 34 protons, 35 electrons, 79 atomic mass
15. Which chemical equation below is not balanced?
O 3 MgSO4 + 2 Na3PO4 + Mg:(PO4), + 3 Na2SO4
O C6H12O6 + 6 0, → 6 C0, + 6 H2O
HBr + AgNO3 → HNO3 + AgBr
2 NaOH + HNO. → NaNO: + 2 H20
Explanation:
yea that doesn't look right you should maybe organize that all a lot more
Which substance has the most thermal energy and will have the most heat flow from it?
A. a stovetop burner on medium (200°C)
B. a nuclear reactor core (1000°C)
C. the human body (36°C)
D. air at room temperature (32°C)
Answer:
B. a nuclear reactor core (1000°C)......
Which one is being shown in this picture?
Answer:
B. REFRACTION.
Is shown in fig.
In the reaction 2 Na(s) + F2(g) --> 2NaF (s), Given 12.5 g of fluorine with enough sodium, what mass of sodium fluoride forms?
Answer:
the mass of sodium fluoride is 15
Explanation:
One mole of F₂ or 38 g produces two moles or 84 g of NaF. Hence, 12.5 g of F₂ will produce 27.6 g of NaF.
What is sodium fluoride?Sodium fluoride is an ionic compound formed by the reaction of sodium metal and fluorine atom . Sodium metal loses one electron to fluorine and thus two moles of sodium and fluorine molecule produces 2 moles of NaF.
The molar mass of F₂ is 38 g. The molar mass of NaF is 42 g/mol. Thus mass of two moles of NaF is 84 grams. As per the balanced reaction, one mole or 38 g of F₂ produces two moles or 84 g of NaF. Thus mass of NaF is calculated as follows:
Mass of NaF = (12.5 g × 84 g) /38 g.
= 27.6 g.
Therefore, the mass of NaF produced by 12.5 g of F₂ in this reaction is 27.6 grams.
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Which are functions of the stomata in the leaves of seed plants? Check all that apply.
-reduce water loss
-make glucose
-absorb sunlight
-take in carbon dioxide
-produce oxygen
NEED CORRECT ANSWER ASAP BEING TIMED
Answer:
Take in carbon dioxide, reduces water loss, and produce oxygen.
Explanation: Hi! I've learned about these things in the past, really tough stuff! Hopefully this helps, I believe the three options above are correct, only one I'm possibly questioning is producing oxygen. Good luck!
Answer:
Take in carbon dioxide, reduces water loss
Explanation:
Calculate the volume occupied by 55.5 moles of water at STP.
Answer:
Volume occupied by 55.5 moles of water gas at STP = 1240 Liters.
Explanation:
1st keep in mind that 'volume' in the context of problems like this apply only to the gas phase form of the substance. Water in solid form (ice) or liquid form (liquid water) do not apply. Volume in this case is referred to as 'molar volume' and is a gas occupying 22.4 liters at STP conditions (0°C, 1Atm).
So, if 1 molar volume of water gas (steam) occupies 22.4 Liters at STP, then 55.5 moles of water gas occupies 22.4 Liters/mole x 55.5 moles = 1243.2 Liters, or 1240 Liters (3 sig. figs.). :-)
Which property (volume , mass , or density) is a measure of the space it takes up?
Answer:
mass
Explanation:
The 38 elements in groups 3 through 12 of the periodic table are called "Alkaline Earth Metals" O True O False
Answer:
FALSE
they're called transition metals
Answer:
false
Explanation:
The 38 elements in groups 3 through 12 of the periodic table are called "transition metals." As with all metals, the transition elements are both ductile and malleable, and conduct electricity and heat.
The survival of aquatic organisms depends on the small amount of O2 that dissolves in H2O . The diagrams above represent possible models to explain this phenomenon. Which diagram provides the better particle representation for the solubility of O2 in H2O , and why?
Answer:
Diagram 1
Explanation:
The solubility of the oxygen gas in water has to do with the interaction of the oxygen with the dipoles in water.
Water is a polar molecule having oxygen as the negative dipole and hydrogen as the positive dipole.
Water can interact with the oxygen atoms in the molecule via intermolecular hydrogen bonds with molecular oxygen as shown in diagram 1.
What is the main goal of cloning? A. To make living things that have identical DNA
B. To improve the process of asexual reproduction
C. To add medicines to the foods that people eat
D. To spread genes from transgenic plants to wild plants
Answer:
A
Explanation:
A p e x