Answer:
I want to say option C: Testing which surfa e is easier to slide a wooden block across.
Explanation:
I'm not 100 % sure though with my answer. I'm truly so very sorry if my answer is wrong. I tried my best.
In physics, friction is said to be the opposing force that resists any object. Testing which surface is more effortless to slide a block across can be used to investigate friction. Thus, option c is correct.
What is friction?Friction has been defined as the resisting force that opposes the movement of objects across the surface. It can also be said as a force that opposes the relative motion of an object.
The friction can be rolling, sliding, fluid, or static depending on the surface and type of object. The frictional force is present only when the object has been in contact of the surface body.
When a surface is tested for sliding the wooden block, then the sliding friction has been used. It is possible as the resistant force of the surface with respect to the block is taken into the consideration.
Therefore, option C. the surface testing for sliding wooden blocks involves friction.
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THIS IS A SCIENCE QUESTION
Which choice describes how temperature differences affect air?
A. Hot air rises, and cold air sinks.
B. Hot air sinks, and cold air rises.
C. Hot air is steady, and cold air moves fast.
D. Hot air moves fast, and cold air rises.
Answer:
A
Explanation:
Hot air is less dense therefore it rises. Cold air is more closely packed therefore it is more dense. Less dense things rise while more dense things sink.
Answer:
A
Explanation:
Think of it like an hot air balloon
Hot air makes it rise and cool air sinks it downwards
How red blood cells different to animal cells
Answer:
By contrast, the red blood cells of mammals lack nuclei and other internal structures found in most animal cells. This simplification allows mammal red blood cells to carry more gas-transporting proteins and to squeeze through smaller blood vessels.
Explanation:
Which of the period 2 homonuclear diatomic molecules are predicted to be paramagnetic?
If the root word "derm” means "skin,” which of these words means "the study of skin diseases and treatment”? dermatologically dermatological dermatologist dermatology
Answer:
it would be dermatology
Explanation:
the first two dont make sense, and a dermatologist is the doctors themselves, so therefore dermatology is the study of it
SOMEONE PLEASE HELP ME
Answer:
1.7
Explanation:
4.52/2.6 = 1.738461538, which can be simplified to 1.7
Answer:
1.7
Explanation:
What is the pH at the equivalence point of the titration of 50.0 mL of 0.300 M NH3(aq) with 0.150 M HCl(aq)?
Answer:
pH = 5.19, at the equivalence point
Explanation:
This is titration of a weak base and a strong acid. pH in the equivalence point will be acid. To determine this pH, we know that in in the equivalence point:
mmoles base = mmoles of base
50 mL . 0.3M = 0.150 M . Volume of acid
Volume of acid = (50 . 0.3)/ 0.15 → 100 mL
Total volume of equivalence point is 50 mL + 150 mL = 200 mL
Neutralization reaction is:
NH₃ + HCl → NH₄Cl
NH₃ + H₃O⁺ ⇄ NH₄⁺ + H₂O
15 15
0 0 15
Ammonia's Kb = 1.8×10⁻⁵
In the equivalence point, we have only ammonium, beacuse all the amonia reacted to the protons. Let's make the equilibrium
NH₄⁺ + H₂O ⇄ NH₃ + H₃O⁺ Ka
I: 15 - - -
Eq: 15-x x x
Ka = 1×10⁻¹⁴ / Kb → 5.55×10⁻¹⁰
[NH₄⁺] = 15 mmoles / 200 mL = 0.075 M
In the equilibrium, we can avoid the 15 - x, because Ka is soo small.
Expression for Ka is [ NH₃ ] . [H₃O⁺] / [NH₄⁺] = 5.55×10⁻¹⁰
[H₃O⁺] = √(5.55×10⁻¹⁰ . 0.075)
[H₃O⁺] = 6.45×10⁻⁶
- log [H₃O⁺] = pH → 5.19
Which substance can be decomposed by a chemical change?
a. calcium
b. potassium
c. sodium
d. sodium chloride
Which of the following is a chemical change?
A. Boiling water using fire
B. Breathing in oxygen and breathing out carbon dioxide
C. Ripping a piece of paper in half
D. Melting gold to make jewelry
A mixture contains NaHCO3 together with unreactive components. A 1.54 g sample of the mixture reacts with HA to produce 0.561 g of CO2. What is the percent by mass of NaHCO3 in the original mixture
Answer:
69.55 (w/w) %
Explanation:
When NaHCO3 reacts with an acid HA, the reaction that occurs is:
NaHCO3 + HA → H2O + NaA + CO2
Where 1 mole of NaHCO3 produce 1 mole of CO2
Thus, we need to convert the mass of CO2 to moles using its molar mass (44g/mol). Then, based on the chemical equation, moles of CO2 produced are equal to moles of NaHCO3 in the mixture. With its molar mass -84g/mol- we can find the mass of NaHCO3 and mass percent:
Moles CO2:
0.561g * (1mol / 44g) = 0.01275 moles CO2 = Moles NaHCO3.
Mass NaHCO3:
0.01275 moles * (84g/mol) = 1.071g NaHCO3
Mass percent:
1.071g NaHCO3 / 1.54g sample * 100
69.55 (w/w) %
A Venn diagram is used to compare and contrast different topics. The items that are unique to each topic are represented in the separate sections of the circles, and the items that are common to both topics are represented in the center overlapping sections. Harlow creates this Venn diagram comparing and contrasting endothermic and exothermic processes. Two overlapping circles are labeled on the left endothermic and on the right exothermic. In the left circle are labels requires energy and examples. In the right circle are labels releases energy and examples. In the overlap is the label involve energy. What can be added to the Examples section of each circle? Endothermic: ice melting into water, and a heat pack becoming warm Exothermic: a glow stick glowing, and fireworks exploding Endothermic: ice melting into water, and an instant ice pack turning cold Exothermic: fireworks exploding, and gasoline burning Endothermic: a glow stick glowing, and a heat pack becoming warm Exothermic: an instant ice pack turning cold, and ice melting into water Endothermic: gasoline burning, and an instant ice pack turning cold Exothermic: ice melting into water, and an instant ice pack turning cold
Answer:
Endothermic: ice melting into water, and an instant ice pack turning cold Explanation:
Answer:
B is the correct answer lol its the only logical one
Explanation:
Find the enthalpy for a constant pressure calorimetry reaction where the reaction occurs in a 250ml aqueous solution. The temperature changes from 25.0c to 26.1 c
Assume that cool = 4.18j/gt
Answer:
[tex]\Delta H=1149.5J[/tex]
Explanation:
Hello!
In this case, since the calorimeter contains a solution for which the specific heat is 4.18 J/g°C, which is equal to that of the water, we can also notice that the density is 1.00 g/mL and therefore the present mass is 250 g. In such a way, we compute the enthalpy change as shown below:
[tex]\Delta H=mC\Delta T[/tex]
Thus, by plugging in the mass, specific heat and temperature change, we obtain:
[tex]\Delta H=250g*4.18\frac{J}{g\°C}(26.1\°C-25.0\°C)\\\\\Delta H=1149.5J[/tex]
Best regards!
In an ionic bond, what do the electrons do in order to form the bond?
1. Share
2. Transfer
Answer:
Transfer
Explanation:
Sharing happens at covalent bond
Transfer happens at ionic bond
This why we say to ion because they give electron get positive or take electron and negative
If you start with 1.5 moles of H2O, how many moles of H4SiO4 do you make?
Answer:
0.75moles of H₄SiO₄
Explanation:
Given parameters:
Number of moles of H₂O = 1.5moles
Unknown:
Number of moles of H₄SiO₄ = ?
Solution:
To solve this problem, we need to write the reaction equation first;
SiO₂ + 2H₂O → H₄SiO₄
From the balanced reaction equation:
2 moles of water will produce 1 mole of H₄SiO₄
So 1.5 moles of water will produce [tex]\frac{1.5}{2}[/tex] = 0.75moles of H₄SiO₄
Methane (CH4) is the main component of marsh gas. Heating methane in the presence of sulfur produces carbon disulfide and hydrogen sulfide as the only products. (a) Write the balanced chemical equation for the reaction of methane and sulfur. (Use the lowest possible coefficients. Include states of matter under SATP conditions in your answer.)(b) Calculate the theoretical yield of carbon disulfide when g of methane is reacted with an equal mass of sulfur.
Answer:
71.25 g
Explanation:
Methane + Sulfur = Carbon Disulfide + Hydrogen Sulfide
The equation is given as;
CH4 + S --> CS2 + H2S
Upon balancing, we have;
CH4(g) + 4S(s) → CS2(l) + 2H2S(g)
Theoretical yield of carbon disulphide;
Equal masses of 120g
The limiting reactant is sulphur It determines how much of the product is formed.
From the equation;
4 mol of S produces 1 mol of CS2
upon converting to masses using; Mass = number of mol * Molar mass
4 mol of S = 4 * 32
1 mol of CS2 = 76g
128g of S produces 76g of C2, 120g would produce ?
128 = 76
120 = x
x = 120 * 76 / 128
x = 71.25g
(a). The balanced chemical reaction will be:
[tex]\rm CH_4\;(g)+\;4\;S\;(s)\rightarrow\;CS_2\;(l)+\;2\;H_2S\;(g)[/tex]
(b). 120 grams of sulfur will produce 71.25 grams of carbon disulfide.
The heating of methane in the presence of sulfur can be given by:
[tex]\rm CH_4\;+\;S\;\rightarrow\;CS_2\;+\;H_2S[/tex]
(a). The lowest possible coefficients have been used to balance the number of elements on both sides i.e. reactant and the product.
[tex]\rm CH_4\;+\;4\;S\;\rightarrow\;CS_2\;+\;2\;H_2S[/tex]
The state of the elements has also been mentioned in the chemical equation. The state of methane is gas, sulfur is solid, carbon disulfide is liquid and hydrogen disulfide is gas.
Thus the balanced chemical reaction will be:
[tex]\rm CH_4\;(g)+\;4\;S\;(s)\rightarrow\;CS_2\;(l)+\;2\;H_2S\;(g)[/tex]
(b). When 120 grams of sulfur reacts, the yield of carbon disulfide will be:
From the balanced equation, 4 moles of sulfur will give 1 mole of carbon disulfide.
4 moles of Sulfur = mole [tex]\times[/tex] molecular weight
4 moles of Sulfur = 4 [tex]\times[/tex] 32
4 moles of Sulfur = 128 grams.
1 mole of carbon disulfide = 76 grams.
So, 128 grams of sulfur produces, 76 grams of carbon disulfide.
Thus, 120 grams of sulfur will produce = [tex]\rm \dfrac{76}{128}\;\times\;120[/tex] grams Carbon disulfide
120 grams of sulfur will produce = 71.25 grams of Carbon disulfide.
Thus, 120 grams of sulfur will produce 71.25 grams of carbon disulfide.
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What do you think the study of chemistry might be about? Thanks for everyone’s help
Answer:
Explanation:
chemistry lol
Which of the following is not a reason why chemical bonds are important
Answer:
I only see B as a answer
Explanation:
What two processes are occurring in this picture
A.erosion and deposition
B.weathering and deposition
C.weathering and erosion
Answer:
C. weathering and erosion
Explanation:
What is MS-Word?MS Word Ki Hai hardware software Ki Hai
Answer:
Ms word is a type of application that is used to make your work more easier nd attractive.
Explanation:
For ex- you can draw a line,you can highlight your text,make your text bold and you can also increase and decrease the font size.
What impact can limiting factors have on a population?
(a) Higher birth rate
(b) Higher death rate
(c) Stable population
(d) Lower death rate
Answer:
The answer is B. Limiting factors can lower birth rates, increase death rates.
How many unshared electrons are found in the lewis dot structure of Carbon Dioxide or CO2?
There are 4 lone pairs of electrons present in the carbon dioxide molecule
PLEASE MARK ME AS BRAINLIEST
Answer:
Explanation:
Carbon dioxide, CO2
Each oxygen contributes 2 electrons - 1 for each bond. That means there are a total of 8 electrons around the carbon, in 4 pairs. Because there are 4 bonds, these are all bond pairs.
Which should have the highest vapor pressure at a given temperature?
A CH4
B C2H6
C C4H10
D they should all be the same
what type of chemical reactions is NaOH(ag)+HCI(ag)=NaCL(ag)+H2O
Answer:
i hope it helps
Explanation:
This reaction involve an acid (HCl) reacting with a base (NaOH), producing a salt (NaCl) and water. Therefore it's a neutralization reaction.
A chemist determines that a sample of petrified wood has a carbon-14 decay rate of 6.00 counts per minute per gram. The decay rate of carbon-14 in fresh wood today is 13.6 counts per minute per gram, and the half life of carbon-14 is 5730 years. What is the age of the piece of wood in years?
Answer:
6,765 years
Explanation:
Calculation to determine the age of the piece of wood in years
First step is to calculate decimal fraction of Carbon-14 that was remaining
Decimal fraction of Carbon-14= 6.00 counts per minute per gram/ 13.6 counts per minute per gram
Decimal fraction of Carbon-14 remaining= 0.4411765
Second step is to calculate the numbers of half-lives that have elapsed
(1/2)^n= 0.4411765
Hence,
n log 0.5 = log 0.4411765
n = 1.18057
Last step is to calculate the length of time that has elapsed
Using this formula
Elapsed length of time=Half life of carbon-14 *n
Let plug in the formula
Elapsed length of time=5,730 years * 1.18057
Elapsed length of time= 6,765 years
Therefore the age of the piece of wood in years will be 6,765 years
How many grams of water (s=1.00 cal/g C) will release 1367 J of heat when cooled from 45.2 C to 36.2 C?
a) 42 g
b) 36 g
c) 31 g
d) 28 g
Answer:
Mass of water = 36 g
Explanation:
Given data:
Amount of energy released = 1367 J = 1367/4.184 = 327 cal
Initial temperature = 45.2 °C
Final temperature = 36.2 °C
Amount of water = ?
Solution:
Specific heat capacity of water is 1 cal/g.°C
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 36.2 °C - 45.2 °C
ΔT = -9°C
-327 cal = m×1 cal/g.°C × -9°C
m = -327 cal/-9cal/g
m = 36 g
the increase in atomic radius as you go down the periodic table is caused by?
Answer: The number of energy levels increases as you move down a group as the number of electrons increases. Each subsequent energy level is further from the nucleus than the last. Therefore, the atomic radius increases as the group and energy levels increase.
how many atoms of oxygen are in a molecule of nitroglycerin
Answer:
i think there are 3 carbon and 5 hydrogen
Explanation:
There are 9 atoms of Oxygen in a molecule of nitroglycerin.
What is Nitroglycerin?Nitroglycerin is also called Trinitroglycerin, It is an oily, thick, colorless liquid.
A vasodilator, nitroglycerin is generally used to relieve anginal chest pain. Currently, the FDA has approved it for the acute prophylaxis of angina pectoris owing to coronary artery disease as well as the acute alleviation of an episode.
It is used in manufacturing explosives.
The molecular formula of Nitroglycerin is C₃H₅N₃O₉
The chemical formula is 1,2,3-trinitroxypropane.
A molecular formula shows the number of atoms present in the compound.
The number of atoms of Carbon present is 3.
The number of atoms of Hydrogen present is 5.
The number of atoms of Nitrogen present is 3.
The number of atoms of Oxygen present is 9.
So, the total number of atoms of Oxygen present is 9.
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50 POINTS
Which is a mixture whose solute particles are individual ions or molecules?
solvent
suspension
colloid
solution
Answer:
A mixture whose components are soluble in each other. ... a solution that has water as its solvent; most have an ionic substance as the solute, may contain a liquid ... The suspensions of particles larger than individual ions or molecules, but the ... This effect is used to determine whether a mixture is a true solution or a colloid.
process of solute particles being surrounded by water molecules arranged in a ... solution. homogeneous mixture consisting of a solute dissolved into a solvent. ... apart from the crystal, the individual ions are then surrounded by solvent particles in a ... are intermediate in size between those of a solution and a suspension.
A suspension is a heterogeneous mixture in which some of the particles ... The particles in a suspension are far larger than those of a solution, so gravity is … ... Particle size: 0.01-1nm; atoms, ions or molecules, Particle size: ... solutions because the individual dispersed particles of a colloid cannot be seen.
Explanation:
When comparing the offspring of sexually and asexually reproducing organisms, we would expect the genetic material of the sexually reproducing organism to -
A. Contain fewer mutations
B. Have fewer organisms
C. Be simpler overall
D. How more variation
Answer:
D more variation.
Explanation:
Asexual reproduction is literally the organism dividing itself into 2, so there is hardly any variation.
The sexual mode of reproduction has been expected to have more variation in the genetic material than the asexual mode of reproduction. Thus, option D is correct.
The asexual mode of replication has been involved with only the parent cell that has been divided into daughter cells with the meiosis and mitosis process.
The sexual mode of reproduction has been accomplished by the fusion of male and female gametes.
The chances of variations or mutations have been higher in the sexual mode of reproduction as two cells fuse together for the formation of the offspring. In the asexual mode of reproduction, the same cell has been divided into the daughter cell, thus the chances of variations have been lower.
Thus, the sexual mode of reproduction has been expected to have more variation in the genetic material than the asexual mode of reproduction. Thus, option D is correct.
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How many dots would the electron dot structure for Be have?
Answer:
it has 2 valence electrons
Explanation:
i hope this helps
Which TWO statements describe the ocean floor giving brainliest pls
Answer:
i think that it is. d and b, im not completely sure but ik d is included
Explanation:
Answer:
think b and a
Explanation:
