Answer:
I think it is true you should go for true
Question 11 of 32
When do scientists form a hypothesis?
A. Before they form a theory
B. After they form a theory
O C. Before they perform an experiment
D. After they perform an experiment
SUBMIT
Answer:
C
Explanation:
a hypothesis always comes first
Answer:
C
Explanation:
They form hypothesis first, then perform the experiment to test the hypothesis. After multiple experiments, they form a theory.
Thus C is correct
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6.3 moles of water h20
Answer:
6.3 moles of water = 6.3*18=113.4 grams per mole
Explanation:
Which statement best describes what would happen to an ecosystem once the sun is removed?
A. The functions within the ecosystem will eventually stop & everything will die off.
B. The ecosystem will continue to thrive; it does not need the sun's energy to work.
C. The ecosystem will look for a different source of energy to use.
D. The ecosystem will instantly stop working.
Answer:
A. The functions within the ecosystem will eventually stop & everything will die off.
Explanation:
Everything is dependent on the sun --starting from the bottom of the food chain, the producers. However, we wouldn't die instantly because "Earth retains heat fairly well, so humans wouldn't freeze instantly."
If you put a piece of zinc into a solution of copper (I) sulfate and allow the single replacement reaction to go to completion, how will you know which of the reactants is the limiting reactant? Write the balanced equation, including the states of matter of the reactants and products, to help support your answer.
Explanation:
Reaction of zinc metal in copper sulfate solution.
[tex]\begin{array}{ll}\text { Oxidation : } & \mathrm{Zn}(s) \rightarrow \mathrm{Zn}^{2+}(a q)+2 e^{-}\\\text {Reduction : } & \mathrm{Cu}^{2+}(a q)+2 e^{-} \rightarrow \mathrm{Cu}(s) \\\hline \text { Full Reaction : } & \mathrm{Zn}(s)+\mathrm{Cu}^{2+}(a q) \rightarrow \mathrm{Zn}^{2+}(a q)+\mathrm{Cu}(s)\end{array}[/tex]
Zinc is listed above copper on the activity series, this means that zinc is more easily oxidized than copper. That is why copper(II) ions can act as an oxidizing agent when put into contact with zinc metal. Ions of any metal that is below zinc, such as lead or silver, would oxidize the zinc in a similar reaction.
All matter has both physical and chemical properties.
True or False
Answer:
F
Explanation:
Because of this, railroads use the reaction to provide molten steel to weld steel rails together when laying track. When 23.00g of iron(III) oxide reacts with aluminum metal, how many moles of molten iron (Fe) are formed
Answer:
0.288 mole of Fe.
Explanation:
We'll begin by calculating the number of mole present in 23.00g of iron(III) oxide (Fe2O3). This can be obtained as follow:
Mass of Fe2O3 = 23 g
Molar mass of Fe2O3 = (56×2) + (16×3)
= 112 + 48
= 160 g/mol
Mole of Fe2O3 =?
Mole = mass /Molar mass
Mole of Fe2O3 = 23 / 160
Mole of Fe2O3 = 0.144 mole
Next, we shall write the balanced equation for the reaction. This is given below:
2Al + Fe2O3 —> Al2O3 + 2Fe
From the balanced equation above,
1 mole of Fe2O3 reacted to produce 2 moles of Fe.
Finally, we shall determine the number of mole of Fe produced by the reaction of 23 g (i.e 0.144 mole) of Fe2O3. This can be obtained as illustrated below:
From the balanced equation above,
1 mole of Fe2O3 reacted to produce 2 moles of Fe.
Therefore, 0.144 mole of Fe2O3 will react to produce = 0.144 × 2 = 0.288 mole of Fe.
Thus, 0.288 mole of Fe is obtained from the reaction.
QUICK
Which of these is a ball and stick model?
Which diagram shows an element?
The number of waves that pass a given point in a certain amount of
time is the waves...
Answer:
100
Explanation:
nsvcscjkvschssvds
Help me plz I don’t know what it’s mean
Answer:
1 has the highest density because it has the most amount of circles in the least amount of space- it is the most densely filled with circles; it is the most dense.
Answer:
image 1 would have the highest density
Explanation:
the closer the molecules are the more solid an object is. if the molecules are far apart and rarely bump into eachother, it is more gaseous. the object in the middle (2) is a liquid
help is science, if you don't know the answer just don't put anything /:
Answer:
Light
Explanation:
Light is a good example of invisible particles. We cannot see light particles aka photon. We only know the light is present by the objects we see. Because we can only see objects when light reflects from them on our eyes.
[I could only think of one example if I can remember one more I'll edit it down]
How many grams of NaCl would be required
to react with 346 mL of 0.607 M AgNO3
solution?
Answer:
Mass = 12.27 g
Explanation:
Given data:
Mass of NaCl are required = ?
Volume of AgNO₃ = 346 mL (346 mL× 1L/ 1000 mL = 0.346 L)
Molarity of AgNO₃ = 0.607 M
Solution:
Chemical equation:
NaCl + AgNO₃ → NaNO₃ + AgCl
Number of moles of AgNO₃:
Molarity = number of moles / volume in L
0.607 M = number of moles / 0.346 L
number of moles = 0.607 M × 0.346 L
number of moles = 0.21 mol
now we will compare the moles of NaCl and AgNO₃.
AgNO₃ : NaCl
1 : 1
0.21 : 0.21
Mass of NaCl:
Mass = number of moles × molar mass
Mass = 0.21 mol × 58.44 g/mol
Mass = 12.27 g
What is causing the Hot Springs to be so hot? What is causing Hot Springs to be so acidic?
Answer:
Hot springs are hot because of geothermal heat. The Hot springs are acidic because hydrogen sulfide and carbon dioxide get in touch with water they evaporate which causes acid.
Explanation:
Oil and water placed in a jar will separate. Even when shaken and mixed, the oil still separates from the water.
Which best describes oil and water?
Oil and water are highly soluble because they have separate chemical properties.
Oil and water have a low solubility because they have separate chemical properties.
Oil and water are highly soluble because they exert different pressures.
Oil and water have a low solubility because they exert different pressures.
Answer:
Probably B?
Explanation:
I don't have one...
Hope it helps I guess..
Answer: i think is B
Explanation: HATE ME IF IM WRONG
A 0.85% saline solution is: a.8.5 mL of saline added to 91.5 mL of water b.85 g of NaCl made up to 1,000 mL of water c.0.85 g NaCl made up to 100 mL of water d.8.5 g NaCl in 100 mL of water
Answer:
c
Explanation:
A 0.85% saline solution would consist of 0.85 g NaCl made up to 100 mL of water.
A 0.85% saline solution contains 0.85% by weight of NaCl. Hence, in order to prepare such a solution, 0.85 g of NaCl is weighed out into a beaker or cylinder and distilled water is added up to the 100 mL mark. On the other hand, 8.5 g of the NaCl can be weighed out and then distilled water added to 1000 mL mark.
The correct option is, therefore, c.
(30 points) Ahhhhhhh can someone help me :'))
I'm not smart and I don't understand how to solve this problem:
Octane, one of the major components of gasoline, burns in air according to this unbalanced equation:
C₈H₁₈ (l) + O₂ (g) ----> CO₂ (g) +H₂O
The formula balanced is: 2 C₈H₁₈ (l) + 50 O₂ (g) ----> 16 CO₂ (g) + 18 H₂O
a) What volume of O₂ at STP is needed to burn 702g (1.00L) of octane?
b) What volume of O₂ at 18°C and 0.975 atm is needed to burn 702g of octane?
Answer:
a. 137.93 dm3
b. 150.61 L
Answer:
C₈H₁₈
Explanation:
A silver ring reacts with compounds containing sulfur in the air to form silver sulfide, a black substance that makes up the tarnish on the surface of silver objects. To remove the tarnish from the ring, students placed it in a pan lined with aluminum foil and added hot water. Baking soda was added to the hot water and stirred. Students made observations about the process. Which observation of this process provides evidence of a chemical reaction?
Question 4 options:
A Hot water heated the aluminum foil.
B The liquid solution changed color.
C The pan was lined with aluminum foil.
D The hot water cooled.
Answer:
c lined with aluminum foil
What is the approximate energy of a photon having a frequency of 4 x 10^7 Hz? (h = 6.6 x 10^-34 J . s)
Answer:
2.64 ×[tex]10^{-26}[/tex] J
Explanation:
I think you should mark it a physics question instead but anyway.
---------------------------------------------------------------------------
The Planck equation should be applied:
E = hv , while E is energy of proton; h is Planck constant; and v is frequency.
E = 6.6 × [tex]10^{-34}[/tex] × 4 × [tex]10^{7}[/tex]
= 6.6 × 4 × [tex]10^{-27}[/tex]
= 2.64 ×[tex]10^{-26}[/tex] J
is methane used as fule
gas true or false
Answer:
its true methane is used as a fuel gas
Explanation:
The model below shows a part of a human body's muscular system.
Muscles are organs that make movement possible. Which organ system is responsible for controlling muscular movement?
A. Endocrine system
B. Skeletal system
C. Nervous system
D. Digestive system
Answer:
you must go to jones im doing the same test
Explanation:
#1 - What is a pure substance? *
1 point
two or more atoms held together by chemical bonds
the attractive force that holds atoms together
a sample of matter that has specific chemical and physical properties
a pure substance made up of two or more different types of atoms joined by chemical bonds
#2 - TRUE OF FALSE: Water is a pure substance.
1 point
True
False
#3 - What is an atom? *
1 point
the smallest unit of an element that keeps the properties of that element
the attractive force that holds atoms together
a sample of matter that has specific chemical and physical properties
a pure substance made up of two or more different types of atoms joined by chemical bonds
#4 - What is a molecule? *
1 point
two or more atoms held together by chemical bonds
the attractive force that holds atoms together
a sample of matter that has specific chemical and physical properties
a pure substance made up of two or more different types of atoms joined by chemical bonds
#5 - What is a chemical bond? *
1 point
two or more atoms held together by chemical bonds
the attractive force that holds atoms together
a sample of matter that has specific chemical and physical properties
a pure substance made up of two or more different types of atoms joined by chemical bonds
#6 - TRUE OR FALSE: Molecules are all the same size. *
1 point
True
False
#7 - What is a compound? *
1 point
two or more atoms held together by chemical bonds
the attractive force that holds atoms together
a sample of matter that has specific chemical and physical properties
a pure substance made up of two or more different types of atoms joined by chemical bonds
#8 - TRUE OR FALSE: Compounds never form in a fixed ratio. *
1 point
True
False
#9 - TRUE OR FALSE: The structure of matter at the atomic and molecular levels is too small to observe directly. *
1 point
True
False
#10 - TRUE OR FALSE: A complex molecule may contain a few atoms bonded together. A simple molecule may contain thousands of atoms. *
1 point
True
False
#11 - What is a crystal? *
1 point
two or more atoms held together by chemical bonds
a substance in which the particles are arranged in an orderly, geometric, and repeating pattern
a sample of matter that has specific chemical and physical properties
a pure substance made up of two or more different types of atoms joined by chemical bonds
#12 - TRUE OR FALSE: Diamond and graphite are both made of carbon atoms. *
1 point
True
False
Answer/Explanation:
#1 - A pure substance is either an element or a compound, making it different from a mixture. A sample of matter that has specific chemical and physical properties is the only one that fits here.
#2 - A pure substance is either an element or a compound, making it different from a mixture. Water is a compound, and thus this would be true.
#3 - An atom is the smallest unit of an element that keeps the properties of that element. Just refer to its definition.
#4 - A molecule is two or more atoms held together by chemical bonds . Again, just refer to its definition.
#5 - A chemical bond is the attractive force that holds atoms together . Jus refer to its definition.
#6 - Molecules are most definitely not all the same size, especially given the huge number of them. This would be false.
#7 - A compound is a pure substance made up of two or more different types of atoms joined by chemical bonds . Just refer to its definition.
#8 - Compounds always form in a fixed ratio, so this would be false.
#9 - If by directly, the problem means with the naked eye, this would be true.
#10 - False. It's reversed.
#11 - A crystal is a substance in which the particles are arranged in an orderly, geometric, and repeating pattern . Just refer to its definition.
#12 -True; to be more specific, they are covalent network solids.
what would you need to do to calculate the molarity of 10g of NaCl in 2kg of water?
A. convert the 10 g of NaCl to Kg of NaCl
B. Convert the 10g of NaCl to moles of NaCl
C. Convert the 2kg of water to liters of water
D. Convert the 2kg of water to moles of water
Answer:
B) we will convert the 10 g of NaCl into moles.
Explanation:
Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.
Formula:
Molarity = number of moles of solute / L of solution
we will convert the 10 g of NaCl into moles.
Number of moles of NaCl:
Number of moles = mass/molar mass
Number of moles = 10 g/ 58.44 gmol
Number of moles = 0.17 mol
1 Kg = 1 L
Molarity = 0.17 mol / 2 L
Molarity = 0.085 mol/L
Molarity = 0.085 M
Answer:
B. Convert the 10g of NaCl to moles of NaCl
pls help me with science
what is a chemical change? and what is a physical change?
In a chemical reaction, there is a change in the composition of the substances in question; in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition.
A chemical change is a change where something new can be formed and normally can not be changed back. Examples of a chemical change are precipitates being formed, gases being formed, quick temperature change rust, bubbling, foaming, burning, etc. A physical change is a change where nothing new is formed and normally can be changed back. For example you painted a wooden block red. If you want, you can always change the color again. Nothing chemically or permanantly happened to it. More examples of a physical change are; color change, change of state, luster, shape, size, hardeness, etc.
:)
What object do you think will take up
more space? Why do you think this?
Answer:
solids
Explanation:
BC they r heavier than liquid and gas
when 3.18 g of copper (||) oxide were carefully heated in a stream of dry hydrogen, 2.54 g of copper and 0.72 g of water were formed determine the number of moles of hydrogen atoms which combine with one mole of oxygen atoms
Answer:
the number of moles of atom is 0.91584
what is dark matter
can we travel faster than speed of light
what is chlorophyll
Answer:
Explaining dark matter and black holes
Here are six big questions about our universe that current physics can’t answer:
What is dark energy, the mysterious energy that appears to be accelerating the expansion of the universe?
What is dark matter, the invisible substance we can only detect by its gravitational effect on stars and galaxies?
What caused inflation, the blindingly fast expansion of the universe immediately after the Big Bang?
For that matter, what caused the Big Bang?
Are there many possible Big Bangs or universes?
Is there a telltale characteristic associated with the death of a universe?
Despite the efforts of some of the world’s brightest brains, the Standard Model of particle physics – our current best theory of how the universe works at a fundamental level – has no solution to these stumpers.
A compelling new theory claims to solve all six in a single sweep. The answer, according to a paper published in European Physical Journal C by Herb Fried from Brown University and Yves Gabellini from INLN-Université de Nice, may be a kind of particle called a tachyon.
Tachyons are hypothetical particles that travel faster than light. According to Einstein’s special theory of relativity – and according to experiment so far – in our ‘real’ world, particles can never travel faster than light. Which is just as well: if they did, our ideas about cause and effect would be thrown out the window, because it would be possible to see an effect manifest before its cause.
Alt
Explanation:
Due to travelling faster than light, dark matter has a higher than usual mass in relation to its resting mass, thus accounting for the large 'missing' mass around galaxies. ... Dark matter is therefore non-baryonic, travelling faster than light and has a mass half that of a photon...
bts army forever.....vzgGgzs0
.......JK
.....justin bieber