Time Period Duration (Millions of Years ago)
Cenozoic 66-0
Mesozoic 252-66
Paleozoic 541-252
Trilobites appeared approximately 521 years ago and disappeared approximately 250 million years ago. During which era did the trilobites live?
a
Cenozoic
b
Mesozoic
c
Paleozoic
d
None of These
Answer:
B
Explanation:
Help pls!! Due in 30 mins!
Which equation represents a single replacement reaction?
1. 2Al(s) + 3Cl2(g) → 2AlCl3(s)
2. 2Al(s) + 6HCl(aq) + 2AlCl3(aq) + 3H2(g)
3. 2AlCl3(s) → 2Al(s) + Cl2(g)
4. AlCl3(aq) + 3KOH(aq) + Al(OH)3(s) + 3KCl(aq)
2. 2Al(s) + 6HCl(aq) + 2AlCl3(aq) + 3H2(g) represents a single replacement reaction
Further explanationA single replacement reaction is a chemical reaction in which one element replaces the other elements of a compound to produce new elements and compounds
Not all of these reactions can occur. We can use the activity series(voltaic series), which is a list of elements that can replace other elements below / to the right of them in a single replacement reaction.
1. 2Al(s) + 3Cl2(g) → 2AlCl3(s)
Syntesis/combination reaction
2. 2Al(s) + 6HCl(aq) ⇒2AlCl3(aq) + 3H2(g)
Single replacement reaction
3. 2AlCl3(s) → 2Al(s) + Cl2(g)
Decomposition reaction
4. AlCl3(aq) + 3KOH(aq) + Al(OH)3(s) + 3KCl(aq)
Double replacement reaction
In a single replacement reaction, one element replaces another one. The reaction that shows the single replacement reaction is:
[tex]\bold { 2Al(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2(g)}[/tex]
Single replacement reaction:It is a chemical reaction in which one element of the reactant compound replaces the other elements of another compound to form a new molecule.In these reactions, a more active element replaces the less active element.
[tex]\bold { 2Al(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2(g)}[/tex]
In the given reaction, aluminum replaces the hydrogen from hydrochloric acid to form Aluminum chloride.
Therefore, the reaction that shows the single replacement reaction is:
[tex]\bold { 2Al(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2(g)}[/tex]
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Metals react by losing valence electrons. Which of the alkali metals loses its valence electrons most easily? Explain.
Answer:
lol you have an aot profile pic
how can you use these materials to test whether land or water heats faster?
Materials:
sand
water
heat lamps
thermometers
cups
Answer:
Put sand in one cup and water in the other. Put two heat lamps at equal height and under each one put the water and sand, this must be done at the same exact time. Set a timer for 5, then 10, then 15, and so forth minutes. Each time measure the temperature of each with the thermometers and write the down. Have a certain temperature you want them to get to and see which gets to it quicker. Then set a new temp 3 times to see if the answer is consistent.
Explanation:
Doing this would test whether land or water heats quicker.
Answer:
heat lamps
Explanation:
What is the change in entropy (AS) when sodium chloride dissolves in water?
The Environmental Protection Agency and health officials nationwide are concerned about the levels
of Radon gas in homes. The half-life of Radon-222 isotope is 3.8 days. If a sample of gas taken from
basement contains 4.38 ug of Radon-222, how long will it be until 0.55 ug will remain? How many half lives?
It takes 11.4 days⇒three half-lives
Further explanationGeneral 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
t1/2=3.8 days
No=4.38 μg
Nt=0.55 μg
[tex]\tt 0.55=4.38\dfrac{1}{2}^{t/3.8}\\\\0.125=\dfrac{1}{2}^{t/3.8}\\\\\dfrac{1}{2}^3=\dfrac{1}{2}^{t/3.8}\\\\3=t/3.8\rightarrow t=3.8\times 3=11.4~days[/tex]
what is the element that is in f block and period 6 that is a rare earth metal
Answer:
Neodymium
Explanation:
need helpppppp hurry pls, i just really need help
Answer:
6.8 mole of O₂
Explanation:
Given expression:
2H₂ + O₂ → 2H₂O
Number of moles of H₂ = 13.6moles
Unknown:
Number of moles of O₂ = ?
Solution:
In the given problem, we are to find the number of moles of oxygen gas that will use up 13.6mole of hydrogen gas;
From the reaction equation;
2 mole of H₂ will completely react with 1 mole of O₂
13.6 moles of H₂ will completely be used up by [tex]\frac{13.6}{2}[/tex] mole of O₂
= 6.8 mole of O₂
can someone solve this plz
βeta decay
carbon atomic mass 14
atomic # 6
Answer:
14/6C your welcome
Explanation:
When the moon is between the earth and the sun what moon phase will this be
Answer: New Moon Phase
Explanation:
Answer:
The New Moon phase
Explanation:
The moon in between the earth and the sun will cause it being a new moon because the sun's light doesn't reach the side of the moon thats facing the earth
HELP DUE TOMMOROW! FAILING CLASS!!! When it would be appropriate to use Radiocarbon dating, Rubidium-Strontium dating, Uranium-Lead dating, and Potassium-Argon dating. Include if the types of dating are used for organic or inorganic things and the time range they are useful for.
Answer:
Uhm if you're failing the class why are you still using brainly to get answers... Where's your momma boy?
Explanation:
It izzz what it izzz
If you have 100 particles of hydrogen and 100 particles of oxygen, how many units of water can you form? Will you use all the particles of both
elements? If not, what will remain?
Answer:
82
Explanation:
i took the assingment
the diagram below shows three containers of gas.
Which list correctly describes the gases in containers R, S, and T?
a R= element s = compound t = mixture
b R= compound s = element T= mixture
cR= element s = mixture t= compound
d r = mixture s= emelem t = compound
ASAP
Answer:
d
Explanation:
The correctly describes the gases in containers R, S, and T is R = mixture S = element and T = compound. Hence option d is correct.
What are gases?Gases are defined as the state of matter where particles often travel very swiftly, far apart from one another, and with little or no attraction to one another. They take up much more space than the liquids or solids from which they are formed, are simple to compress, and expand to fill their containers.
Particles make up all matter; these particles can be single atoms or atoms that have been chemically combined to form molecules. This fact allows us to divide matter into three general categories: elements, compounds, and mixtures. All the atoms in an element are of the same kind. A compound is created when more than one kind of atom is chemically bonded.
Thus, the correctly describes the gases in containers R, S, and T is R = mixture S = element and T = compound. Hence option d is correct.
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Analyze how friction can be both a positive and negative aspect in our everyday lives. Use examples to support your statements.
Answer:
For example, friction between our shoes and the floor stop us from slipping and friction between tyres and the road stop cars from skidding. Friction is sometimes unhelpful. For example, if you don't lubricate your bike regularly with oil, the friction in the chain and axles increases.
Explanation:
Calculate the percent composition of C6H12O6
Answer:
Did you just let your cat walk on your keyboard? XD
Could you explain this a bit better please?
I'll answer the question in the replies of this comment if you can give me a bit more information.
Explanation:
May I have brainliest please? :)
A 23.7 g piece of iron at 54.9°C is cooled and releases 338 J of heat. The specific heat of iron is 0.450 J/g°C.
Answer:
The heat capacity and the specific heat are related by C=cm or c=C/m. The mass m, specific heat c, change in temperature ΔT, and heat added (or subtracted) Q are related by the equation: Q=mcΔT. Values of specific heat are dependent on the properties and phase of a given substance.
Explanation:
Answer:
23.2 degrees c
Explanation:
1. Which of these is not one of the main 6 forms of energy?
O a. Nuclear energy
O b. Chemical energy
O c. Light energy
O d. Electromagnetic energy
Answer:
Chemical energy
Explanation:
Chemical Energy
what is atomic?................................................
Answer:
oh I'm here thanks for your points
Answer:
thanx for the points
Explanation:
How many moles of carbon dioxide molecules
are there in 50g of carbon dioxide?
Answer:
3.011×1023 individual carbon dioxide molecules
3. IDENTIFY the following reactions as Oxidation / Reduction reactions ?
a) PbO + H2 --> Pb + H2O
b) ZnO + C --> Zn + CO
c) H2S + Cl2--> 2HCl + S
d) Fe203 + 3C0 --> 2Fe + 3CO2
e) PbS + 4H202 --- PbSO4 + 4H2O
Explain what occurs when an electron is given energy from an outside source.
Answer:
An electron can become excited if it is given extra energy, such as if it absorbs a photon, or packet of light, or collides with a nearby atom or particle.
Explanation:
Mark me brainliest.
6. Look carefully at the following diagram. It does not obey the law of conservation of matter. Explain why it does not follow the law of conservation of matter using evidence
from the diagram.
Answer:
Sort of answer, but it'll lead you in the right direction I hope.
Explanation:
I mean, ofc, the molecules or atoms or whatever the circles are can't be put together that way bc matter says so. It looks like the other diagram is showing water or gas, and if it were turning into the one on the right, then it would usually either settle into water if it was gas or become a single solid object like water. If this is gas, then it doesn't make sense, because gas particles are always separate from each other.
The chemical equation below shows the amount of the reactants used and the amount of only one of the products formed. How much water (H2O) should be formed in this chemical reaction? CH4 mass 4 + 2O2 mass 16 CO2 11 + 2h2O mass ?
Answer:
CH4 + 2O2 → CO2 + 2H2O
Explanation:
This is all i could come up with im sorry.
The amount of water formed in the given chemical reaction is 9 grams.
What is Stoichiometry?Stoichiometry is the calculation for the determination of the relative amount of reactants and products in chemical reactions. Stoichiometry is based on the law of conservation of mass where the total mass of the reactants in reaction equals the total mass of the products.
If the quantity of one reactant is known and the quantity of the product can be determined empirically, then the quantity of the other reactants can be calculated.
Given chemical equation is:
CH₄ + 2O₂ [tex]\longrightarrow[/tex] CO₂ + 2H₂O
16g 32g 44g 32g (from their molecular masses)
The amount of methane, oxygen, and carbon dioxide is 4g, 16g, and 32 g respectively.
16g of methane react with oxygen = 32g
4g of methane will react with oxygen = 8g
It means here methane is the limiting reagent as the given amount of oxygen is more than reacted one. So CH₄ will decide the amount of water.
16g of methane produces water = 32g
Then 4g of methane will produce water = (32/16) × 4 = 9 g
Therefore, 9 grams of water should be formed in this reaction.
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the first 5 elements (in increasing order) that are found in group 18
Answer:
Today, I will present the first eighteen elements which are Hydrogen, Helium, Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Fluorine, Neon, Sodium, Magnesium, Aluminum, Silicon, Phosphorus, Sulfur, Chlorine, and Argon.
First 5: Hydrogen. The first and simplest element on the periodic table.
Helium. a very light colorless element that is one of the six inert gasses.
Lithium. A very soft, light metal.
Beryllium. A very light metal; although it is 3 1/2 times the density of Lithium.
Boron. The fifth element in the periodic table.
Explanation:
Is cell membrane a plant or animals cell
Answer:
They both have a cell membrane, however a plant also has a cell wall.
Explanation:
What is the role of CdKs? to create enzymes that produce chemical changes to signal the cell to move to the next phase of the cell cycle to build structural components of DNA and energy-rich substances to activate the cyclins that cause progression of the cell cycle
Answer:
It’s b
Explanation:
Answer:
Regulation of the cell cycle is carried out by which of the following? Check all that apply.
CdKs
cyclins
What is the role of CdKs?
to signal the cell to move to the next phase of the cell cycle
Explanation:
As the frequency decreases the wavelength...
Answer:
Increase
Explanation:
Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency of the wave: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths.
Also can someone help me with this one as well, thank you! :)
Answer:
a. The density of the aluminum will change if the sample gets too big.
Explanation:
Since increasing its size increases its volume hence it affects the value of its density by decreasing.
note: Density = mass/volume.
Carbon makes up part of all life forms on Earth. The human body, for example, is about blank % carbon.
For the water, what color is the hydrogen molecule?
Answer:
White is the color of a hydrogen molecule
Answer:
green. It is white when separate, but it turns green when it's formed into water.
Explanation: