Answer: Percent composition by element
Element Symbol Mass Percent
Hydrogen H 6.498%
Carbon C 19.357%
Nitrogen N 22.574%
Oxygen O 51.571%
HOPE THIS HELPS
4. DBearded waste of Co-60 must be stored until it is no longer radioactive. Cobalt-60
waste weighing 14.5g has been in storage før 26.5 years. How much of this radioisotope
was present when the sample was put in storage?
464 g radioisotope was present when the sample was put in storage
Further explanationGiven
Sample waste of Co-60 = 14.5 g
26.5 years in storage
Required
Initial sample
Solution
General formulas used in decay:
[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]
t = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
Half-life of Co-60 = 5.3 years
Input the value :
[tex]\tt 14.5=No.\dfrac{1}{2}^{26.5/5.3}\\\\14.5=No.\dfrac{1}{2}^5\\\\No=\boxed{\bold{464~g}}[/tex]
Which element is most likely to have an oxidation number of +2?
O sodium (Na)
O magnesium (Mg)
O chlorine (CI)
O argon (Ar)
The answer is magnesium (Mg).
How many kilocalories of heat are released when 75 g of steam at 100 degrees Celsius is converted to ice at 0 degrees Celsius?
Answer:
∴ Q = -7.52kCal
Explanation:
Using the formula for specific heat capacity:
Q = mcΔT
where ΔT = change in temperature (final - initial) = (0 - 100)°C = -100°C
m = mass (g) = 75g
c = specific heat capacity = 4.2 J/g°C in water
⇒ Q = 75 × 4.2 × -100
= -31,500J
But 1J - 0.000239kCal
∴ Q = -7.52kCal
Let me know if I can be of further assistance.
Need help with this ASAP
Answer:
yes ?
Explanation:
...............................
Balance the equation below:
Fe+CuSO4
[Fe+CuSO4 = FeSO4+Cu is not the correct answer]
Answer:
Fe+CuSO4 ⇒ FeCu+SO4
Answer:
Fe + CuSO4 = Fe2 (SO4)3 + Cu - Chemical Equation Balancer
Explanation:
To balance Fe + CuSO4 = Cu + FeSO4 you'll need to be sure to count all of atoms on each side of the chemical equation. When we balance equations with polyatomic ions, like SO4 2- it is helpful to consider the SO4 as one item as long as there is a SO4 on both sides of the chemical equation.
Once you know how many of each type of atom you have you can only change the coefficients (the numbers in front of atoms or compounds) to balance the equation.
Important tips for balancing chemical equations like Cu + FeSO4 | Iron and Copper(II) Sulfate:
- Only change the numbers in front of compounds (the coefficients).
- Never change the numbers after atoms (the subscripts).
- The number of each atom on both sides of the equation must be the same for the equation to be balanced.
does the mean molecular speed chnage as much as the temperature as the water heats up? explain please help
Explanation:
When water is heated up then its molecules move rapidly from one place to another. Hence, kinetic energy of the molecules tend to increase.
Also, K.E = [tex]\frac{3}{2}kT[/tex]
where, T = temperature
Therefore, more is the increase in temperature more will be the mean molecular speed change in the water molecules.
As a result, mean molecular speed change increases with increase in temperature and vice-versa.
help!!
The volume of air in the lungs of a typical human is 6.0 L. Traditional free divers, known for their ability to hold their breath during long dives while gathering objects from the ocean bottom, could descend underwater to a depth of 30 m where the pressure is four times that at the surface. What would be the volume of air in their lungs at 30 m?
please!!
Answer: these are for questions 1,2,4,5,7
Explanation: number 3: as the pressure in the volume decreases, the volume increases causing it to expand and eventually blow.
number 6: because the temperature and the amount of gas don’t change, these terms don’t appear in the equation. What Boyle’s law means is that the volume of a mass of gas is inversely proportional to its pressure. This linear relationship between pressure and volume means doubling the volume of a given mass of gas decreases its pressure by half.
hope this helps :))
Which element is considered to be a transition element?
F
Sn
Cu
Na
Answer:
Cu
Explanation:
From the given choices only Copper is considered a transition element.
Transition elements are found between the groups IIIB - IIB on the periodic table.
These elements are also said to be d-block elements.
Copper is the 29th element on the periodic table of elementsIt belongs to the first row of the transition elements. Fluorine is in the p-block and a member of the halogenTin is the 5th groupNa is an alkali - metal15. If I make 94.8 L of O2, how many grams of H2O did I start with? (Show ALL work)
Answer:
double
Explanation:
.
I have a brick, dimensions 4 cm tall, 9 cm wide, and 25 cm long, with a mass of 1250 g. What is the density?
Answer:
1.389
Explanation:
P = m / V
m = 1250
V = 4x9x25 = 900
1250/900 = 1.388889
What are the 3 primary states of matter?
Answer:
solid liquid gas
Explanation:
solid liquid gas
UNDERSTANDING CONCEPTS-Fill in the Blanks:
Periodic Trends: Write either INCREASE or DECREASE or VARIABLE:
17.lon size = Atom → Cation
18. Atomic radius (size) = Down a group
19. Electronegativity = Across a period left
20. Ionization energy = Down a group
Atom Anion
Across a period right
Up a group
Across a period left
Answer:
17 decrease
18 increase
19 increase
20 decrease
Explanation:
What caused the shielding effect to remain constant across a period
Answer:
When moving from left to the right of a period, the number of electrons increases and the strength of shielding increases. As you move across period the number of shells remain same, the shielding effect will also remain constant.
Explanation:
Look at the questions labelled A, B, C, D. A How many substances are there in drinking water? B How much fluoride is in drinking water? C Is fluoride soluble in drinking water? D Should fluoride be added to drinking water? Which one of the questions cannot be answered by science alone? Tick one box.
Answer:
Magnesium, calcium and sodium.
Explanation:
Magnesium, calcium, sodium, and other beneficial minerals are the substances present in drinking water. Different regions have different fluoride concentration in their water such as in sea water, fluoride level is 1.1 mg/L while in surface water, the concentration is 0.01–0.3 ppm. Yes, fluoride is soluble in water. No, fluoride should not be added to drinking water because it harm for health. All the questions can be answered by science because it is related to chemistry.
please help last assignment of the day
In this qn, you use the mole formula,
amount (mol) = mass (g) ÷ molar mass
(molar mass is the mass number of an element, which u can find by referring to the periodic table)
so by subbing in the values given to you, you can find the answer
5. amount of Cu = 55.9 ÷ 63.5 = 0.880mol (3sf)
6. amount of N2 = 340 ÷ 2(14.0) = 12.1mol (3sf)
(note: you multiply the molar mass of N by 2 as there are 2 N atoms)
for qn 7 and 8, youre finding the mass and not the amount. By bringing the molar mass over to the other side of the formula, you get
mass = amount (mol) × molar mass
thus,
7. mass of Fe = 0.063 × 55.8 = 3.52g (3sf)
8. mass of H2 = 94.7 × 2(1.0) = 47.4g (3sf)
extra things to take note of:
- likewise, you can also find the molar mass of an element by using
molar mass = mass(g) ÷ amount(mol)
^^ this is commonly only needed when you need to find the molar mass of an isotope. the question will give you the amount and mass of the element, and you just need to factor them in to find your answer.
- typically, you use 3 sf in your final answer and 5sf in your working. remember to write (3sf) at the end of your number statement when necessary.
- when you get an answer of (eg.) 0.6mol, you still need to write it in 3sf, so your answer would be 0.600mol
Help please How much water do you think the average household in the US uses every day?
Answer:
About 140 gallons?
Explanation:
The portion of Earth underneath the crust containing the asthenosphere and the mesosphere is the
Answer:
lithosphere
Explanation:
Answer:
mantle
Explanation:
A neutral aluminum atom is ionized and loses 3 electrons. What is the
charge of the resulting aluminum ion?
Explanation:
The neutral aluminium atom loses all 3 of its valence electrons to obtain a stable octet structure.
The aluminium ion has a positive charge of 3.
=> Al3+, Charge = +3.
What is the mass of 0.572 moles of Al?
Some people have one sickle cell gene and one normal gene. They have few defctive cells and no symptoms because the sickle cell gene and one copy of a normal gene?Describe the process
Answer:
The sickle cell gene is recessive to the normal gene
Please find the description below
Explanation:
Sickle cell is a blood disease inherited genetically from one's parents. The sickle cell is associated with the blood genotype of an individual. The allele for sickle cell trait is S, while that of the normal gene is A. In this gene, the allele for normal gene (A) is dominant over the allele for sickle cell (S).
Hence, people that have one sickle cell gene (S) and one normal gene (A) will have an AS genotype. The individual will have few defective cells and no symptoms because the phenotypic expression of the sickle cell allele has been masked by the normal one.
How many grams are in .705 moles of Cr?
Answer:
51.9961 grams
Explanation:
Just did worksheet
earth science includes the study of air , water and land
true or false
Answer: ITSSSS TRUE!!!!!
Explanation:
what does a negative cell voltage mean?
A. the reaction releases energy
B. the reaction is non-spontaneous
C. the reaction can never happen
D. the reaction is spontaneous
Answer:
I think its B but i may be wrong
Explanation:
Sorry if im wrong!! Took that test but i dont rm the answer well enough to be for sure
The reaction is non-spontaneous
this is the correct answer
Balance the chemical equation below using the smallest possible whole number stoichiometric coefficients.
P4(s)+NaOH(aq)+H2O(l)➪
PH3(g)+Na2HPO3(aq)
A chemical equation is said to be balanced if the quantity of each type of atom in the reaction is the same on both the reactant and product sides. In a balanced chemical equation, the mass and the charge are both equal. P₄ + 4NaOH + 2H₂O → 2PH₃ + 2Na₂HPO₃.
A chemical equation is said to be balanced if the quantity of each type of atom in the reaction is the same on both the reactant and product sides. In a balanced chemical equation, the mass and the charge are both equal.
A chemical equation must balance according to the rule of conservation of mass. According to the rule, mass cannot be generated or removed during a chemical process.
To know more about balanced chemical equation, visit;
https://brainly.com/question/14015590
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Cancer cells grow so rapidly thatthey have a higher rate of anaerobic metabolism than most body tissues, especially at the center of a tumor. Can you use drugs thatpoison the enzymes of anaerobic metabolism in the treatment ofcancer? Why, or why not?
Answer:
No, you cannot
Explanation:
One of the major properties a cancer drug must have is that, it must be highly specific. If a drug that poisons enzymes of anaerobic metabolism is used on a cancer patient, it should be noted that the drug will not only kill cancer cells but will also kill under cells that make use of anaerobic metabolism. Hence, this drug is not a specific to cancer cells but will also affect other normal cells in the patient's body. Thus, it would be wrong to use such drugs to treat cancer.
1. Which piece of laboratory glassware is used to make precise
concentrations of solutions?
A. volumetric flask
B. beaker
C. buret
D. test tubes
Answer: I beleive it is the volumetric flask.
Explanation:
I searched it up.
A compound with a mass of 48.72g is found to contain 32.69g of zinc and 16.03g of sulfur. What is the percentage composition of the compound
Answer:
dic
Explanation:
Identify each of the following compounds as binary or ternary.
a. nickel (III) oxide
b. copper(II) iodide
c. tin(IV) nitride
d. chromium (II) bromide
e. iron (III) phosphide
f. lithium hydroxide
g. Potassium sulfate
h. Ammonium phosphide
i. Barium nitrate
j. cobalt (II) phosphate
Answer:
binary compounds have 2 different elements, and ternary compounds have 3
Nickel(III)oxide: binary, Ni2O3
Copper (II)iodide: binary, CuI2
Tin(IV) nitride: binary, Sn3N4
Chromium (II)bromide: binary, CrBr2
Iron(III)phosphide: binary, FeP
Explanation:
In gymnastics, a gymnast must be able to balance on a balance beam. What is the best explanation for what forces are acting on the gymnast on a balance beam?
Explanation:
When the gymnast is standing straight up, gravity acts on the gymnast but the gymnast is able to stay relatively stable.Tihis happens because her center of mass is directly above the beam which means that gravity is pushing her down onto the beam.
PLEASE I WILL RATE YOU AND I DONT HAVE TIME PLEASEEE The volume of a substance is 20cm³ and its mass is 80 gm. Will this substance sink or float in water. Explain the reason showing calculation.
Answer:
80g=0.08kg
20cm=0.02m
density=m/v
= 0.08/0.02
=4kg/m^3
it is less than density of water so it floats