If I could change something in my previous science classes, it would have been the fact that I struggled in the question concerning exponents. It was simple one, but I don't know how I didn't understood that. For example, if there is a question with a calculation "xy²", then I would first multiply x and y, and then calculate the exponent. I did 3 of the questions wrong because of this, it was when I was in 7th grade. I wish I had not done this kind of silly mistake. I an in 10th grade and understand it well now, though.
A sample taken from a layer of mica In a canyon has 2.10 grams of potassium-40. A test reveals it to be 2.6 billion years old. How much potassium-40 was in the sample originally if the half-life of potassium-40 is 1.3 billion years? A. 4.20 g B. 8.40 g C. 12.6 g D. 16.8 g the E. 25.2 g
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option b) is correct answer.
Describe how you would prepare a supersaturated solution
Answer:
A supersaturated solution contains more dissolved solute than required for preparing a saturated solution and can be prepared by heating a saturated solution, adding more solute, and then cooling it gently. Excess dissolved solute crystallizes by seeding supersaturated solution with a few crystals of the solute.
Explanation:
Which is the formula mass of (NH4)2SO4?
96.07 amu
114.12 amu
116.17 amu
132.17 amu
Answer:
132.17amu
Explanation:
(14.01+1.01 multiplied by 4)=18.05×2=36.1
36.1+32.07= 68.17
16.00×4=64
68.17+64=132.17
Answer:
132.17 amu
Explanation:
just took the test. got 100
Name the following bases.
Fe(OH)3
- iron(III) hydroxide
- iron(II) hydroxide
- iron hydroxide
Answer:
1
Explanation:
Ferric Hydroxide
3. 1
Fe. (OH)
Fe(OH)3
Answer:
iron(III) hydroxide
Explanation:
I just took the quiz!
1. Necesitas un "cubo concentrado" (de esos que se usan para sazonar las comidas Maggie, ricostilla) dos vasos de vidrio o plástico y agua (caliente y fría). 2.Agrega al vaso con agua fria la mitad de un cubo concentrado y déjala reposar unos minutos. Prepara el segundo vaso con agua caliente y agrégale la otra mitad del cubo. 3. Argumenta tus observaciones en relación con lo observado y con la teoria vista. ¿Como influye la temperatura en este experimento?
why is it important of having regular supervision of the market?
Analysis of an ore of calcium shows that it contains 13.61 g calcium and 21.77 g oxygen in a 46.28-g sample. Calculate the percent composition of this compound.
Answer:
29.41% of Calcium and 47.04% of Oxygen
Explanation:
The percent composition of an atom in a molecule is defined as 100 times the ratio between the mass of the atom and the mass of the molecule.
The mass of the molecule of the problem (Ore) is 46.28g. That means the percent composition of Calcium is:
13.61g / 46.28g * 100 = 29.41% of Calcium
And percent composition of Oxygen is:
21.77g / 46.28g * 100 = 47.04% of Oxygen
Which of the following processes does NOT facilitate containment?
Answer:
b is the answr
Explanation:
The correct answer is Option (B) Enrichment of Uranium-235 is done.
What is Containment? Containment is the process of preventing pollution or contamination of the immediate site environment by dust, chemicals, and other materials to prevent corrosion.What is Corrosion?Corrosion is a natural process that converts a refined metal into a more chemically stable oxide.The degree of containment is directly proportional to the degree of toxicity present in the corrosion preventive substance being applied.Why other options are incorrect?Option (A) , (C) , (D) are the options that facilitate containment because these are the processes for preventing contamination.
Hence Option (B) is correct because enrichment of uranium-235 is achieved by the process of conversion So , It does not facilitate containment
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BJECTIVE TYPE QUESTIONS
Fill in the blank spaces by choosing the correct words from the words given in list.
List : composition, heat, chemical, photosynthesis, physical
1. Heating of zinc oxide is a
change.
2. Burning of coal is a
change.
3. There is a change in state and
during a chemical change.
4. Plants make their food by the process of
5.
energy is generally given out or absorbed during a chemical change
Answer:
1.Physical change
2. Chemical change
3. Heat
4.photosynthesis
5. composition
HELP ME ASAPPPP PLZZZZZ!!!!!
For the reaction C + 2H2 → CH4, how many grams of hydrogen are required to produce 16.8 moles of methane, CH4 ?
Which of the following are true for an element? (i)Atomic number= number of protons + number of electrons (ii)Mass number = number of protons+ number of neutrons (iii)Atomic mass= number of protons= number of neutrons (iv)Atomic number = number of protons = number of electrons
Answer:
ii and iv
Explanation:
atomic mass is the sum of protons and neutrons
protons ( postively charged) usually have the same number like electrons( negatively charged)
Using dobereiner's triads, what conclusion could have been made about magnesium
Answer:
Triads were groups of 3 elements with similar chemical and physical properties. Beryllium, magnesium, and calcium are all earth alkalis found in the earth
Explanation:
2. Nitric oxide contains 46.66% nitrogen and 53.34% oxygen. Water contains 11.21% hydrogen and 88.79% oxygen. Ammonia contains 17.78% hydroger and 82.22% nitrogen. Use these data to verify the law of reciprocal proportions.
Answer:
The law of reciprocal proportions states that if two elements react individually with a given weight of a third element, the ratio of the masses with which they combine with the third element are either the same or a simple multiple of the ratio of the masses with which they combine with each other
The compounds formed includes;
1) Nitric oxide, NO
Nitrogen = 46.66% × 30.01 = 14
Oxygen = 53.34% × 30.01 = 16
2) Water, H₂O
Hydrogen = 11.21% × 18.01528 = 2
Oxygen = 88.79% × 18.01528 ≈ 16
3) Ammonia, NH₃
Hydrogen = 17.78% × 17.031 ≈ 3
Nitrogen = 82.22% × 17.031 ≈ 14
The ratio of nitrogen to oxygen in nitric oxide = 14:16 = 7:8
The ratio of nitrogen to hydrogen in ammonia = 14:3
The ratio in which hydrogen and oxygen combine with nitrogen = 3/16
The ratio of hydrogen and oxygen combine with each other in water = 2/16
Therefore, the ratio with which hydrogen and oxygen combine with nitrogen, is (2/3) times the ratio with which they combine with each other, which verifies the law of reciprocal proportions
Explanation:
Which of the following about a balanced chemical reactions is
NOT true?
O A properly written chemical equation will include the states of matter
for every substance in the reaction.
O The number of atoms of each element must be the same for both
reactants and products.
A balanced chemical equation must follow the Law of Conservation
of Matter
A balanced chemical equation must always include coefficients on
every reactant and product.
Answer:
A balanced chemical equation must always include coefficients on every reactant and product.
Explanation:
A balanced chemical equation does not need to include coefficients on every reactant and product.
For example, below is a balanced chemical equation in which the reactants and the products have no coefficients whatsoever:
NaOH(aq) + HCl (aq) -----> NaCl (s) + H2O (l)
Of course, a properly written chemical equation must include the states of matter of all the substances in the reaction and the number of atoms of each element must balance both in the reactant and product sides of the equation. Generally, a balanced chemical equation must obey the law of conservation of matter which opines that matter can neither be created nor destroyed but can only be converted from one form to another.
Hence, that a balanced chemical equation must always include coefficients on every reactant and product is not true.
Element 'X' forms a chloride with the formula XCl2, which is a solid with high melting point. X would most likely be in the same group of the periodic table as:
I) Si
2) Al
3) Mg
4) Na
pls pls answer fast
Answer:
Mg
Explanation:
Mg forms 2+ ions and mgcl2 has a melting point over 700°C I believe.
Name five metal which are both dilute and memorable? class 10
What is the change in enthalpy of the first reaction below, given the enthalpies of the other two reactions?
Here's the reactions:
There was a formatting issue with the specific chemistry symbols, there all correct in the picture below
2C(s) + O2(g) → 2CO(g)
C(s) + O2(g) → CO2(g) ∆H0= -394 KJ/mol
CO(s) + 1/2 O2(g) → CO2(g) ∆H0= -283 KJ/mol
There was a formatting issue with the specific chemistry symbols, there all correct in the picture below
Answer:
∆H0 = -222kJ/mol
Explanation:
Using Hess's law, we can find the ΔH of a reaction from the sum of another related reactions as follows:
Using the reactions:
(1) C(s) + O2(g) → CO2(g) ∆H0= -394 KJ/mol
(2) CO(s) + 1/2 O2(g) → CO2(g) ∆H0= -283 KJ/mol
Twice (1):
2C(s) + 2O2(g) → 2CO2(g) ∆H0= 2*-394 KJ/mol = -788kJ/mol
The inverse reaction of (2):
-(2) CO2(g) → CO(g) + 1/2 O2(g) ∆H0= 283 KJ/mol
Twice this reaction:
2*-(2) 2CO2(g) → 2CO(s) + O2(g) ∆H0= 2*283 KJ/mol= 566kJ/mol
Now, the sum of 2*(1) - 2*(2) produce:
2C(s) + 2O2(g) + 2CO2(g)→ 2CO2(g) + 2CO(g) + O2(g) ∆H0= -788kJ/mol + 566kJ/mol
Subtracting the molecules that ar in both sides of the reaction:
2C(s) + O2(g) → 2CO(g) ∆H0 = -222kJ/mol
The intermediate product formed during the production of urea is,
Answer:
Arginine is intermediate product formed during the production of urea
The key combination is ornithine, on which the urea molecule is 'created'; intermediates in the procedure contain citrulline and arginine.
What is the Production of Urea?
The urea cycle is a procedure of conversion of toxic ammonia to negligibly toxic urea. Consequences of the urea cycle are 1 molecule of urea, 2 molecules of ADP, and 1 molecule of both AMP and fumaric acid.
When Ammonia and carbon dioxide recovery During urea decomposition a mixture of gaseous carbon dioxide and also ammonia is accumulated and also immersed into a dilute aqueous urea resolution.
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Please hurry this is due tomorrow morning
A student is studying the ways different elements are similar to one another. Diagrams of
atoms from four different elements are shown below.
Which two atoms are of elements in the same group in the periodic table?
F Atom 1 and Atom 2
G Atom 1 and Atom 4
H Atom 2 and Atom 3
J Atom 3 and Atom 4
Cual es la longitud de onda de un foton emitido durante la transicion desde el stado n=5 al estado n=3 en atomo Hidrogeno? Dar como respuesta de la longitud de onda en nm (nanometros)
Answer:
1302 nm
Explanation:
Del formulario de Rydberg para longitud de onda
1 / λ = R (1 / nf ^ 2 - 1 / ni ^ 2)
1 / λ = 1.097 × 10 ^ 7 (1/3 ^ 2 - 1/5 ^ 2)
1 / λ = 1.097 × 10 ^ 7 (0.11 - 0.04)
1 / λ = 1.097 × 10 ^ 7 (0.07)
= 1,302 × 10 ^ -6 m
o 1302 nm
A galaxy that has an undefined shape is best classified as a(n)
galaxy.
Answer:
irregular galaxy
pls give brainliest :)
Answer:
irregular galaxy
it is undefined shape
can u plz solve it n send the answer
1. Cl2 + H2O → HOCl + HCl
2. Tooth decay starts when when the pH of the mouth is lower than 5.5. Tooth enamel is made up of calcium phosphate and it is one of the hardest substances of the body. But it is corroded when the pH is less than 5.5. The bacteria of our mouth produce acids by degradation of sugar and food particles remaining in our mouth after eating food.
3. Fluorine salts are added in toothpaste to protect our teeth from tooth decay. Fluorine salts are mildly basic, so they neutrelise the acid in our mouth that leads to tooth decay.
4. Tincture of iodine is iodine, pottasium iodide and sodium iodide dissolved in ethanol. Iodine acts in an antiseptic manner by destroying microbial proteins and DNA.
5. Tincture of iodine is clear and reddish brown liquid.
how do i calculate the concentration of a certain solution
Answer:
Divide the mass of the solute by the total volume of the solution. Write out the equation C = m/V, where m is the mass of the solute and V is the total volume of the solution. Plug in the values you found for the mass and volume, and divide them to find the concentration of your solution.
“during times of personal crisis we may feel the need to engage the services of a therapist to help us with out problems”
fact or opinion and why
Answer:
That is a fact.
Explanation:
A therapist can help support you going forward and when in a personal crisis.
A therapist can help us mentally during a personal crisis. This is a fact. because there are personal therapist who helps us to recover from negative thoughts and mental illness.
What is psychotherapy?Individual psychotherapy is the use of psychological techniques to address emotional and personality issues or disorders. In other words, there are treatments that assist in treating emotional disorders in a manner similar to how a doctor would treat a fever or cold.
Milder emotional conflicts to serious psychopathologies might all be a part of these issues. As a result, both those who are depressed and those who are having marital problems can seek counselling.
The problems that can be healed through psychotherapy include difficulties coping with stressors , trauma and related experiences, mental illnesses such as depression, anxiety an so on.
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Which statement describes the "Law of Conservation of Mass" for the following reaction?
4 Fe + 302 -
2 Fe₂O₃
Select one:
tion
a.
grams of Fe + grams of Fe2O3 = grams of O2
O b. grams of O2 + grams of Fe2O3 = grams of Fe
O c. grams of Fe +grams of O2 = grams of Fe203
O d. None of these.
Name this ionic compound.
Answer:
c
Explanation:
why water molecules remain associated in liquid water
Answer:
Answer: They are attracted to each other due to their electrostatic attraction. All that means is the hydrogen atom is positively charged, while the oxygen atom is negatively charged. ... The hydrogen of one water molecule will bond to the oxygen atom of another molecule.
Answer:
They are attracted to each other due to their electrostatic attraction. All that means is the hydrogen atom is positively charged, while the oxygen atom is negatively charged. ... The hydrogen of one water molecule will bond to the oxygen atom of another molecule.
Explanation:
It's said that not all electrons in an atom have the same amount of energy. Is it the same for protons? Because if it's not then how come they have the same atomic number at the end?
Answer:
When an atom has an equal number of electrons and protons, it has an equal number of negative electric charges (the electrons) and positive electric charges (the protons). The total electric charge of the atom is therefore zero and the atom is said to be neutral.
I HOPE THIS HELPS !!!!!!!!!!!
While studying bacterial cells, scientists measure the lengths of the cells in one colony. The chart shows their data. The scientists notice that one measurement stands out. How should the scientists best deal with this measurement?
Answer:
The scientists should best deal with this measurement by stating that there was an error during measuring and collect further data.
The graph shows the change in concentration of one of the species in the reaction
A + B + C→D.
If the graph indicates the reaction rate, then the concentration of which species is plotted?
A
B
C
D
Answer:
its D
Explanation:
Took the test
The specie whose concentration is plotted is D. The rate of reaction is how quickly or slowly hat a reaction proceeds.
Rate of reactionThe term rate of reaction refers to how quickly or slowly hat a reaction proceeds. A reaction rate plot involves the concentration of the species plotted against time.
Now we can see from the plot that concentration is increasing with time. Since the concentration of products increases with time, then the specie whose concentration is plotted is D.
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hii pls help me to balance chemical equations
ammonia + oxygen ------> nitrogen + water
Answer:
Explanation:
Ammonia = NH3
Oxygen = O2
When these two (2) chemical elements react together, they form two chemical compound which are nitrogen oxide and water.
NH3 + O2 -----> NO + H2O
We would balance the chemical equation like this;
NH3 + 3O2 -----> 4NO + 2H2O
