Scientists hypothesize that a certain species of animal existed in the past.
But, fossils of the species have never been found. Which two statements
could explain why?
A. There were very few members of the species.
B. Their bodies decomposed quickly.
O C. Their bodies contained radioactive atoms.
D. Minerals seeped into their bones.
SUBMIT
Answer: Fossils of the species have never been found because:-
a. There were few members of the species.
d. Their bodies decompose quickly.
For an organism to become fossil it is important that it do not decompose before it get buried by sediments.
What are fossils?
A fossil is any preserved remains, impression, or trace of any once-living thing from a past geological age.
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Answer: The answer is B and A.
Explanation:
I took the test!
50 Points for whoever does it and shows their work. Maya has four glasses of milk. The temperature and the amount of milk in each glass are shown: Glass A: 20 grams of milk at 10 °C Glass B: 50 grams of milk at 80 °C Glass C: 20 grams of milk at 50 °C Glass D: 50 grams of milk at 80 °C Which statement is correct?
Answer:
A. 20 grams of milk at 10°C
Explanation:
Since we refrigerate milk, it would be cooler than the room temperature, which standard norm is 25°C. So the milk has to be colder than the room temperature. Therefore, our answer is A.
Answer: A is the correct answer
Explanation:
The temperature of room temperature is more than that and you need to keep it colder, hope this helped!
The correct name for molecule I is
Molecule I
I
|
CH3-CH-CH3
a. Iodopropane
b. 2-iodylpropane
c. 2-iodopropane
D. Propyliodine
14. The correct name for molecule III is
Molecule III
F
|
C= CH
——-
a. 2-Fluoroeth 1-yne
b. Fluoroethyne
C. Fluoroethene
D. Methylfluorine
16. Synthetic chlorinated hydrocarbons such as dioxins and furans are usually greater pollution hazard then natural organic substances because synthetic hydrocarbons are
a. More volatile
b. Less water soluble
C. Less Biodegradable
D. More chemically reactive
Question 17.
Sources of pollutants
1. High temperature combustion
2. Pulp and paper industry
3. Pesticides
4. Sour gas plants
Match each source of pollutant as numbered above with its pollutant as listed below. Use each number only once
17. Dioxins/furans
18. SO2(g)
19. Nox(g)
20. Phosphates
Answer:
c). 2-iodopropane
14) C). Fluoroethene
16) D). More chemically reactive
17) 1). High temperature combustion - Dioxins/furans
2). Pulp and paper industry - SO2(g)
3). Pesticides - Phosphates
4). Sour gas plants - Nox(g)
Explanation:
The correct name for molecule I would be '2-iodopropane' where the number 2 reflects the position of iodine. There are three carbons and 8 hydrogen atoms which reflect that it is an alkane compound. In the given carbon chain. In this chain of three carbons, iodine is present on the second carbon. Therefore, option C is the correct answer.
14). The appropriate name for molecule III exemplifies Fluoroethene as it consists of two carbons due to which it belongs to the 'ethane' group and it bears the prefix 'fluoro as it belongs to fluorine group and the suffix '-ene' due to double bond.
16). Synthetic hydrocarbons are 'more chemically reactive' and therefore, it generates greenhouse gases and leads to climate change, global warming, depletion of the ozone layer, etc.
17). 1). Dioxins are generated as a result of high-temperature combustion processes like commercial waste incineration or burning of fuels.
2). Pulp and paper industry releases various gases like nitrogen oxide, sulfur dioxide SO2(g), carbon dioxide, etc.
3). Phosphate is the pollutant released from pesticides that badly affects the fertility of the soil.
4). Nox(g) nitrogen oxide released by sour gas plants and coal-fired emissions is a major contributor to increased greenhouses gases and global warming.
How many moles of Al would be produced from 12.85 moles of Al2O3?
Al2O3 → AL + O2
Select one:
O a. 25.7
O b. 6.43
O c. 19.3
d. 8.61
PLEASE HELP ME
Sugar can be converted to carbon dioxide and water by burning in air or by metabolic reactions inside living cells. How are these reactions similar and how are they different?
Answer:
These reactions are similar because the process is similar and the products are carbon dioxide they are different because the substances are different to outgo these reactions
Explanation:
Q10. Calcium fluoride can be made from the reaction of calcium metal with fluorine gas. The image shows this reaction. Explain how the product is formed in terms of electron movement and what the final electron configurations are
Answer:
The answer to your question is given below
Explanation:
In this reaction, the calcium metal, Ca loses two electrons to form calcium ion, Ca^2+ and two fluorine atoms, F receives the two electrons to form two fluoride ion, F^-.
This is illustrated by the following equation:
Ca —> Ca^2+ + 2e
2F + 2e –> 2F^-
Ca + 2F + 2e —> Ca^2+ + 2F^- + 2e
Cancel out 2e
Ca + 2F —> Ca^2+ 2F^-
Thus, the electronic configuration can be written as follow:
Before combination:
Calcium, Ca (20) => 2, 8, 8, 2
Two fluorine atom, F (9) => 2, 7 and 2, 7
After combination:
Calcium ion, Ca^2+ => 2, 8, 8
Two fluoride ion, F^- => 2,8 and 2,8
In the reaction Ca + Cl2 → CaCl2, what is the mole ratio of chlorine to calcium chloride?
Select one:
O a. 2:3
O b. 2:1
O c. 1:2
O d. 1:1
PLEASE HELP ME
Answer:
D. 1:1
Explanation:
For every 1 mole of chlorine (Cl₂), there is one mole of calcium chloride (CaCl₂).
So, the mole ratio of chlorine to calcium chloride is 1:1.
Hope this helps. :)
The mole ratio of chlorine to calcium chloride in the given chemical reaction is 1:1.
What is the stoichiometry?Stoichiometry of the reaction gives idea about the relative amount of moles of reactants and products present in the given chemical reaction.
Given chemical reaction is:
Ca + Cl₂ → CaCl₂
From the stoichiometry of the given reaction it is clear that,
1 mole of chlorine = reacts with 1 mole of calcium chloride
So, mole ratio = Chlorine / calcium chloride = 1:1
Hence required mole ratio is 1:1.
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Consider preparing ammonia gas by the following reaction:
N2(g) + 3H2(g)
===>
2NH3(g)
If you have 28.02 g of N2 and excess H2, how many grams of NH3(g) can be produced.
6.06 g
14.01 g
34.08 g
68.16 g
28.02 g
Answer:
34.08 g
Explanation:
Take the atomic mass of N=14.0, H=1.0/
no. of moles=mmass/molar mass
no. of moles of N2 used = 28.02 / (14x2)
=1.0007mol
From the equation, the mole ratio of N2 : NH3 = 1: 2,
so one mole of N2 produces 2 moles of NH3.
Using this ratio, we can deduce that the no. of moles of NH3 = 1.0007x2
= 2.001428mol
mass = no. of moles x molar mass
Hence,
mass of NH3 produced = 2.001428 x (14+1x3)
= 34.03
≈C
procedure to find out if the penny is real copper with copper wire
Answer:
Four ways to test a copper penny are given below:-
Explanation:
Firstly, take a quick look only at the color of the penny. Zinc pennies may appear patchy, irregular whereas copper-gold coins may seem more probable to be orange or even chocolate. Secondly, drop your penny on the floor and hear the noise it's making. The copper penny would have a "started to ring" sound in this situation, whereas the zinc penny should "clunk." Third, you can weigh the centimeter. You'll need an accurate scale weighing in grams. The penny of copper will weigh 3.11 grams while the penny of zinc weighs 2.5 grams. In the end, look at the date. If your penny was taken out of circulation before 1982, 95 percent copper and 5 percent zinc will be made. Beginning in 1982, pennies had just 2.5 percent copper and 97.5 percent zinc in them. Pennies from any of the two formulations made in 1982 may be produced.
As Danny was pouring cereal for his breakfast, he noticed that the cereal box says that the cereal contains 5 milligrams of iron per serving. Danny decided to perform an experiment to test this claim. He found that the cereal contains 4.6 milligrams of iron per serving. Based on Danny's measurement, the value reported on the label is ( CORRECT OR INCCORECT) because A: (IT IS DIFFERENT FROM THE VALUE DANNY MEASURED) B: (IT IS REORTED TO THE NEAREST MILLIGRAM) C: (IT USES THE SAME UNITS THAT DANNY USED).
Answer:
Correct, because B it is reported to the nearest miligram
Explanation:
4.6 rounded up is 5
2. If the reaction of 5.75 moles of sodium with excess hydrofluoric acid is able to produce 2.49 mol H2, what is the percent yield of hydrogen gas?
Unbalanced equation:
Na + HF –> NaF + H2
94.2%
86.5%
43.3%
23.1%
Answer:
86.5%
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
2Na + 2HF –> 2NaF + H2
Next, we shall determine the theoretical yield of the hydrogen gas, H2. This is illustrated:
From the balanced equation above,
2 moles of Na reacted to produce 1 mole of H2.
Therefore, 5.75 moles of Na will react to produce = (5.75 x 1)/2 = 2.88 moles of H2.
Therefore, the theoretical yield of Hydrogen gas, H2 is 2.88 moles.
Finally, we shall determine the percentage yield of Hydrogen gas, H2. This can be obtained as follow:
Actual yield of H2 = 2.49 moes
Theoretical yield of H2 = 2.88 moles
Percentage yield of H2 =.?
Percentage yield = Actual yield /Theoretical yield x 100
Percentage yield = 2.49/2.88 x 100
Percentage yield = 86.5%
Therefore, the percentage yield of Hydrogen gas, H2 is 86.5%.
1. A 10.0 g sample of propane, C3H8, was combusted in a constant-volume bomb
calorimeter. The total heat capacity of the bomb calorimeter and water was 8.0
kJ/°C. The molar heat of combustion of propane is -2 222 KJ/mol. If the starting
temperature of the water was 20 °C, what will be the final temperature of the
bomb calorimeter?
Answer:
The final temperature of the bomb calorimeter is 82.98°C
Explanation:
The given information are;
The mass of the propane sample = 10.0 g
The heat capacity of the bomb calorimeter = 8.0 kJ/°C
The molar heat of combustion of propane is -2,222 kJ/mol.
The starting (initial) temperature of the water, T₁ = 20°C
The final temperature of the bomb calorimeter = T₂
The molar mas of propane = 44.1 g/mol
The number of moles, n, of propane present in 10.0 g of propane is found as follows;
[tex]Number \ of \ moles \ of \ propane, \ n = \dfrac{Mass \ of \ propane}{Molar mass \ of \ propane} = \dfrac{10}{44.1} = 0.227 \ moles[/tex]Which gives;
The heat, Δh, released from the combustion of 10.0 g of propane = 0.227 × -2222 kJ/mol
Δh = -503.85 kJ/mol
Heat gained by the calorimeter = Heat released from the combustion of 10.0 g of propane = 503.85 kJ/mol
Change in heat, Δh[tex]_c[/tex] in the calorimeter = Heat capacity × Temperature change
Δh[tex]_c[/tex] = m × C
503.85 kJ/mol = 8.0 kJ/°C × (T₂ - 20°C)
T₂ = -503.85 kJ/mol/(8.0 kJ/°C) + 20°C = 82.98°C
The final temperature of the bomb calorimeter = 82.98°C
How many Liters of 18 M H2SO4 are needed to make 0.5 L of 1.5 M H2SO4
Answer:
0.04 L
Explanation:
The following data were obtained from the question:
Concentration of stock solution (C1) = 18M
Volume of stock solution needed (V1) =?
Concentration of diluted solution (C2) = 1.5M
Volume of diluted solution (V2) = 0.5L
The volume of the stock solution needed can be obtain by using the dilution formula.
This is illustrated below:
C1V1 = C2V2
18 x V1 = 1.5 x 0.5
Divide both side by 18
V1 = (1.5 x 0.5)/18
V1 = 0.04L
Therefore, the volume of the stock solution needed is 0.04L.
The functional group for an ester is: RCHO RCOOH RCOOR ROH
Answer:
RCOOR
Explanation:
Odyssey ware
RCOOR is the functional group for an ester. An ester is an organic molecule created when an acid and an alcohol interact. The general structure of the compound is RCOOR, where R is an aryl or alkyl group.
What is the way for the structure ?This functional group is made up of an alkyl or aryl group (R) and a carbonyl group (C=O) linked to an oxygen atom. Two additional carbon atoms, one of which is a member of the carbonyl group and the other of which is a member of the alkyl or aryl group, are joined to the oxygen atom.
The connection between the oxygen atom and the hydrogen atom of the acid is broken during the interaction of an acid with an alcohol to create an ester.of a fresh connection between the oxygen atom and the alcohol's alkyl or aryl group. As a result, the RCOOR functional group is created.
Esters are significant organic substances with many different uses. They serve as solvents and are employed in the synthesis of flavours, perfumes, polymers, medicines, and other products. They are also employed in the creation of fragrances and cosmetics, as well as as lubricants. Other organic compounds can be made using esters as intermediates.
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What qualifications do you need to be a research scientist?
A. High IQ
B. College degree
C. High school diploma
D. Ph.D
Answer:
Ph.D
Explanation:
For the most part, research scientists need a bachelor's degree in a highly associated field. A master's degree or a doctorate is frequently expected.
Which lifestyle is most likely to lead to infertility in a male ?
A man who works as a mechanic
A man who works as a computer programmer and sits at desk magority of the day
A semi professional athlete
A man who works for a company’s that applies pesticides to lawns
Answer:
The second on, A man who works as a computer programmer and sits at desk magority of the day.
Explanation:
Answer:
Explanation:
The only answer I can think as being possible is the last one. Pesticides are chemicals that go after unwanted animal life. They do not know that they should not attack human beings.
Infertility could very well be one of the side effects of a pesticide. There are others as well. Some pesticides go after the central nervous system (think mice and rats) and those are dangerous to use and to leave around.
The others all involve occupations that either require authentic abilities or mental astuteness. Neither should affect a man's ability to reproduce.
Bromine water was added dropwise to test tubes containing aqueous solutions of bromide, chloride, and iodide. lodide was oxidized to iodine; bromide and chloride gave no reaction Arrange Br 2 ,Cl 2 ,I 2 in order of their strength as an oxidizing agent.
Answer:
Cl₂ > Br₂ > I₂
Explanation:
An oxidizing agent gains electron for itself by removing electrons from other reactants during a reaction. Oxidation is the loss of electrons. Chlorine can take electron from bromine and chlorine while bromine can take electron from iodine, therefore chlorine is a more oxidizing agent than bromine and iodine while bromine is a more oxidizing agent than iodine.
Oxidizing ability decreases down the group.
Therefore Cl₂ > Br₂ > I₂
SERE
What type of energy is the sum of an object's potential and kinetic energy?
mechanical energy
electromagnetic energy
chemical energy
thermal enemy
Answer:
Mechanical energy
Answer:
Mechanical Energy
Explanation:
The mechanical energy is the sum of the objects potential energy (energy the object possess due to its position) and its kinetic energy (energy the object possess due to its motion). Adding this two energies together, gives the total mechanical energy.
Determine the [H+] or [OH−] for each of a solutions at 25°C.
Solution B: [H3O+] = 9.99 x 10^-9 M
Solution B: [OH-] = ?
Solution C: [H3O+] = 0.000777 M
Solution C: [OH-] = ?
Answer:
Solution B: [OH-] = 1×10^–6 M
Solution C: [OH-] = 1×10^–6 M
Explanation:
Solution B:
Hydronium ion concentration, [H3O+] = 9.99×10^–9 M
Hydroxide ion concentration, [OH-] = ?
The Hydroxide ion concentration, [OH-] can be obtained as follow:
[H3O+] × [OH-] = 1×10^–14
9.99×10^–9 × [OH-] = 1×10^–14
Divide both side by 9.99×10^–9
[OH-] = 1×10^–14 / 9.99×10^–9
[OH-] = 1×10^–6 M
Therefore, the Hydroxide ion concentration, [OH-] is 1×10^–6 M
Solution C:
Hydronium ion concentration, [H3O+] = 0.000777 M
Hydroxide ion concentration, [OH-] = ?
The Hydroxide ion concentration, [OH-] can be obtained as follow:
[H3O+] × [OH-] = 1×10^–14
0.000777 × [OH-] = 1×10^–14
Divide both side by 0.000777
[OH-] = 1×10^–14 / 0.000777
[OH-] = 1.29×10^–11 M
Therefore, the Hydroxide ion concentration, [OH-] is 1.29×10^–11 M
In this molecule, what's the formal charge on the central O atom?
A. -1
B. -2
C. 0
D. +1
In water, oxygen is covalently bonded to two hydrogen atoms. Oxygen has the formal charge of zero and hydrogens also has the formal charge of zero.
What is formal charge ?Formal charge of an atom is the charge it possess in a compound. The formal charge of an atom is found out from its valence electrons, lone pair of electrons and bond pairs.
The equation of formal charge is written as follows:
Formal charge = Valence electrons - (Lone pair + bond pair)
In water, oxygen covalently bonds to two hydrogen atoms. The bond pair of electrons from oxygen is 2.
number of valence electrons in oxygen = 6
no.of lone pairs = 4
Then FC = 6 - (4 + 2) = 0
Therefore, the formal charge of oxygen in water is zero.
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