Answer:
B
Explanation:
the number of protons never changes even if the atomic mass changes
Hyenas eat larger mammals like antelope and wildebeest, but will also eat lizards, birds, snakes, and insects. What type of teeth would you expect a hyena to have?
Answer:
Large Sharp Teeth
Explanation:
i got a 100 on my test!
Large Sharp Teeth !
i got it right on my quiz
Calculate the percent composition (out of 100) by weight of potassium in potassium carbonate decahydrate.
Answer:
12.26%
Explanation:
MM K = 39.1 g/mol
MM K2CO3 . 10H2O = 2x39.1 + 12.01 + 3 x 15.99 + 10 x 18.02= 318.38 g/mol
% by weight = (MM K/MM K2CO3.10H2O ) x 100= (39.1/318.8) x 100=12.26 %
The percent composition by weight of potassium in potassium carbonate decahydrate is 13.98%
Let's represent the chemical formula of the compound as follows;
potassium carbonate decahydrate = CH₂0KO₁₃
The molecular mass of the compound can be calculated as follows:
Molecular mass of CH₂₀KO₁₃molecular mass = 12 + 20 + 39 + (16×13) = 279 g/molmass of potassium = 39 g
Therefore,
% mass of potassium = 39 / 279 × 100
% mass of potassium = 3900 / 279
% mass of potassium = 13.9784946237
% mass of potassium = 13.98 %
learn more on percentage composition here: https://brainly.com/question/3905173
Which example indicates that a chemical change has occurred? *
1 point
A. When two aqueous solutions are mixed, a precipitate is formed.
B. As ammonium nitrate dissolves in water causes the temperature to decrease.
C. Alcohol evaporates when left in an open container.
D. Water is added to blue copper(II) chloride solution. The resulting mixture if lighter blue in color.
Answer:
A. When two aqueous solutions are mixed, a precipitate is formed.
Explanation:
The precipitate (a solid substance that falls from the liquid) is the result of a chemical reaction taking place between the liquids.
The other three answer choices are indicative of physical changes (temperature change, phase change, color change).
When two aqueous solutions are mixed, a precipitate is formed indicates that a chemical change has occurred.
Hence, option A is correct answer.
What is Chemical change ?Chemical change are those changes in which substance changes chemical composition. These changes are permanent changes. In chemical change new substances formed and in chemical change substances can not get back into its original form. It is irreversible change.
What is Physical change ?Physical changes are those changes in which substance changes physical properties only. Properties like temperature, pressure, shape, color, size, state (solid, liquid and gas). These changes are temporary in nature. In physical change no new substances formed. It is reversible change.
Now, check all the options one by one:
Option (A): When two aqueous solutions are mixed, a precipitate is formed is a chemical change. Since precipitation indicate a chemical reaction (that is double displacement reaction).
Option (B): As ammonium nitrate dissolved in water causes the temperature to decrease is a physical change because heat energy is absorbed here and it is a endothermic reaction.
Option (C): Alcohol evaporates when left in an open container is a physical change because evaporation is a physical change as it changes the state from liquid state to gas state.
Option (D): Water is added to blue copper (II) chloride solution. The resulting mixture if lighter blue in color is a physical change as properties like change in color is physical change.
Thus, from above conclusion we can say that When two aqueous solutions are mixed, a precipitate is formed indicates that a chemical change has occurred.
Hence, option A is correct answer.
Learn more about physical and chemical change here: https://brainly.com/question/17166994
#SPJ2
thermal energy is what we call energy that come from ___ of matter
I NEED AWNSER ASAP What forms as a result of the wind's frictional force on water?
deep sea currents that move in a path opposite to the wind currents
surface currents that move in a path similar to the wind currents
surface currents that move in a path opposite to the wind currents
deep sea currents that move in a path similar to the wind currents (the sub is science)
Answer:
2 no. is the answer surface currents that move in a path opposite to the wind currents
Answer:
no.2 is the answer of your question
Can someone please help me!!
Answer:
Less in the top
your well wisher
How many grams equal 4.3 x 1024 atoms of oxygen (02)?
Answer: 248.66g
Explanation:
4.3e24 / 6.23e23 = 6.9 mols O2
6.9(18.02*2)=248.66
pond water with microscopic organisms inside mixture or pure substance
Answer:
it's mixture
Explanation:
since pond is composed of not only microbes and also more aqatic animals so I think pond become mixture but not pure substance am I right or not...
Which of the following do scientists use to form a hypothesis?

A.
A question and observations

B.
A conclusion and data

C.
A conclusion and a theory

D.
A question and opinions
Explanation:
The scientific method involves making observations and asking questions. Scientists form hypotheses based on these observations and then develop controlled experiments to collecting and analyze data. Using this data, they are able to draw conclusions and form questions for new scientific research.
:)ᴍᴀʀᴋ ᴀꜱ ʙʀᴀɪɴʟɪꜱᴛ
Whoever gets these 2 right gets brainliest! :)
the first one is A covalent bond.
the second one is Answer: B Decomposition
What causes a ionic bond to occur
Answer:
when the valence (outermost) electrons of one atom are transferred permanently to another atom
The equation below illustrates the process of
Pb2+ (aq) + 11- (aq) → Pblu (s)
a) dissolution
b) precipitation
c) decomposition
Answer:
The correct answer is - b) precipitation.
Explanation:
In the given question the lead ion in an aqueous solution is mixed with the Leutium ion in an aqueous solution and forms an insoluble or solid salt. This type of reaction is referred to as precipitation reactions in chemistry.
Such reactions are helpful in determining if a particular ion is present in the solution or not.
Pb2+ (aq) + lu- (aq) → Pblu (s)
A student plans a two-step synthesis of 1-ethyl-3-nitrobenzene from benzene. The first step is nitration of benzene to give nitrobenzene, and the second step is a Friedel-Crafts alkylation using CH3CH2Cl and AlCl3. The plan is flawed because: A : When the alkyl halide interacts with AlCl3, the resulting carbocation can rearrange before it has a chance to react with the aromatic ring. B : Nitrobenzene is too deactivated (by the nitro group) to undergo a Friedel-Crafts alkylation. C : The nitro group will direct the incoming alkyl group para position, rather than to the meta position. D : A blocking group is required to achieve this synthesis.
Answer:
Nitrobenzene is too deactivated (by the nitro group) to undergo a Friedel-Crafts alkylation.
Explanation:
The benzene ring in itself does not easily undergo electrophilic substitution reaction. Some groups activate or deactivate the benzene ring towards electrophilic substitution reactions.
-NO2 ia a highly deactivating substituent therefore, Friedel-Crafts alkylation of nitrobenzene does not take place under any conditions.
This reaction scheme is therefore flawed because Nitrobenzene is too deactivated (by the nitro group) to undergo a Friedel-Crafts alkylation.
how many moles of nitrogen gas are produced in the reaction if we started with 6 moles of ammonium nitrate
The percent by mass of iron(III) 1 Fe2S3
is _____%
Answer:
percent=69.94%
help plz and will give brainly
What % of original U238 remains after three half lives?
1-50
2-25
3-12.5
4-6.25
Answer:
12.5
Explanation:
After three half-lives, one eighth (1/2 x 1/2 x 1/2) of the uranium-238 will remain. One-eighth equals 12.5%
Click to review the online content. Then answer the question(s) below, using complete sentences. Scroll down to view additional questions.
Online Content: Site 1
How did the gold rush transform Australia? (Site 1)
marking brainliest
Answer:
In 1851 gold-seekers from around the world began pouring into the colonies, changing the course of Australian history. The gold rushes greatly expanded Australia's population, boosted its economy, and led to the emergence of a new national identity.
Explanation:
Answer:
People from all over the world look for gold and in 1851 people started forming colonies to look for it which had a huge impact on the history of Australia. The gold rushes increased Australia's population which improved its economy.
I need help ASAP plz :)
hi, if your looking for extra points (50+) and brainiest here is ur chance, answer this question correctly plz
Its the warm air what helps them also of energy of the sun
If you began a reaction with the following ions in solution, what would be the net ionic equation?
Na+, PO43–, Fe2+, and NO3–
Answer:
2 PO₄³⁻(aq) + 3 Fe²⁺(aq) ⇒ Fe₃(PO₄)₂
Explanation:
Let's consider the complete ionic equation between the ions present. It includes all the ions and the insoluble compounds (Fe₃(PO₄)₂ is insoluble).
Na⁺(aq) + 2 PO₄³⁻(aq) + 3 Fe²⁺(aq) + NO₃⁻(aq) ⇒ Fe₃(PO₄)₂ + Na⁺(aq) + NO₃⁻(aq)
The net ionic equation includes only the ions that participate in the reaction (not spectator ions) and the insoluble compounds.
2 PO₄³⁻(aq) + 3 Fe²⁺(aq) ⇒ Fe₃(PO₄)₂
5. Given the formula of a substance:
H Hн H
IT
C-C-C=C
1
H
H
What is the total number of shared electrons in a
molecule of this substance?
A) 22
B) 11
C) 9
D) 6
A) 22
In a single bond one pair of electrons is shared, with one electron being contributed from each of the atoms. Double bonds share two pairs of electrons and triple bonds share three pairs of electrons. Bonds sharing more than one pair of electrons are called multiple covalent bonds.In the given molecule:
There are total 7 single bonds and 2 double bonds.
As we know, In a single bond one pair of electrons is shared and double bonds share two pairs of electrons.
Thus,
Total number of shared electrons in a molecule= 7*2+2*4=14+8=22
So, total number of shared electrons in a molecule is 22.
Therefore, option A) is correct.
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help please guys i need it
Answer:
Amplitude
Explanation:
Hope I helped :)
mathdrrggeszdrsz seer r-
Answer:
130!!
Explanation:
Help me with my homework plzy
Answer:
the second answer choice i think
Explanation:
Balance the chemical equation
C2H6+O2 = CO2 +H2O
Use the balanced equation in the image below. How many moles of
ammonia (NH3) will be produced if 2.22 moles of nitrogen (N2) are used?
(Assume there is excess hydrogen gas.) SHOW YOUR WORK TO RECEIVE
CREDIT. *
N2 + 3H2 → 2 NH3
Since there is excess hydrogen, that means that the concentration of hydrogen is not limiting.
According to the balanced chemical equation:
every mole of N2 and every 3 moles of H2 we obtain 2 moles of NH3. Since we have the amount of N2 and excess of hydrogen, we only need to work with the amount of N2.
1 mol of N2 will produce 2 moles of NH3
so now we can get a conversation tool :
moles of N2 * (2 moles of NH3/ 1 mole of N2) = moles of NH3
(2.22 mol of N2 x 2) ÷ 1 = 4.44 mol of NH3
Guys please help me i will mark brainly!
Answer:
D
Explanation:
what grade percentage is developing, proficient, exceeding, and emerging?
Answer:
Grade A is the best percentage that is developing, proficient, exceeding, and emerging
The smallest arteries in your body are called _____. arterioles capillaries veins bronchioles
Answer: arterioles
Explanation: