Answer:
All zeros between other significant digits are significant. The number of significant figures is determined by starting with the leftmost non-zero digit. The leftmost non-zero digit is sometimes called the most significant digit or the most significant figure. For example, in the number 0.004205, the '4' is the most significant figure.
Explanation:
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*1. Which statement about the temperature of a phase changes in electrostatic forces holding the molecules is correct?
A. The temperatures of which a substance changes phases is dependent of the size of the molecules in the substance.
B. The strength of the forces between molecules in a substance depends on the number of filled electron shells.
C. The temperatures at which a substance changes phases indicate the relative strength of the forces between molecules in the substance.
D. The strength of the forces between molecules in a substance is the strongest at higher temperatures.
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*2. Which list shows the phases of matter in order from strongest collective electrostatic forces to weakest collective electrostatic forces?
A. Gas, solid, liquid
B. Gas, liquid, solid
C. Liquid, solid gas
D. Solid, liquid, gas
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*3. Which change happens when water boils?
A. The forces between water molecules become stronger, and the bonds between atoms in the water remain unchanged.
B. The forces between water molecules are unchanged, and the bonds between the atoms in a water break.
C. The force is between water molecules in the bonds between the atoms in the water molecules break.
D. The forces between water molecules break, and the bonds between the atoms in water are unchanged.
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*4. A sample of calcium carbonate is cooled. Which change happens to the molecules of calcium carbonate in the sample?
A. The forces weaken, and the molecules move around.
B. The molecules break apart and then form stronger forces.
C. The forces strengthen, and the molecule structure becomes more rigid.
D. The molecules vibrate more and weaken the forces.
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*5. The boiling point of acetone is lower than the boiling point of ethanol. Based on this information, which conclusion can be drawn about the two substances?
A. The intramolecular bonds in acetone are stronger than the intramolecular bonds in ethanol.
B. The intermolecular forces in ethanol are stronger than the intermolecular forces in acetone.
C. The intramolecular bonds in ethanol are stronger than the intramolecular bonds in acetone.
D. The intermolecular forces in acetone are stronger than the intermolecular forces in ethanol.
Answer:
see below
Explanation:
1. The temperatures at which a substance changes phases indicate the relative strength of the forces between molecules in the substance.
2. solid, liquid, gas
3. The forces between water molecules break, and the bonds between the atoms in water are unchanged.
4. The forces strengthen, and the molecule structure becomes more rigid.
5. The intermolecular forces in ethanol are stronger than the intermolecular forces in acetone.
The the degree of intermolecular interaction between molecules determines the magnitude of boiling point of the substance.
During phase change, a substance moves from one state of matter to another. The temperature at which a phase change occurs is determined by the strength of the forces between molecules in the substance. The relative magnitude of intermolecular forces between molecules in different states of matter is solids > liquids > gases.
During boiling, energy is imparted to the molecules of a liquid. When this occurs, the forces between water molecules break, and the bonds between the atoms in water are unchanged.
We must recall that the molecules of a substance are in constant random motion. The average kinetic energy of molecules is proportional to temperature. As a sample of calcium carbonate is cooled, the forces between molecules strengthen, and the molecule structure becomes more rigid.
The magnitude of intermolecular interaction affects the boiling point of a liquid. The stronger the magnitude of intermolecular interaction,the higher the boiling point. As such, ethanol having hydrogen bonds between its molecules has a higher boiling point than acetone which only posses weaker dipole - dipole interactions.
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Which of the following is an example of climate?
A. The polar regions have long winters and short, cool summers.
B. Humidity levels are high today.
C. Canada experienced an unusually warm summer this year.
D. Tornados formed across Oklahoma yesterday.
Answer:
A. The polar regions have long winters and short, cool summers.
Explanation:
Climate is location based, however is over long periods of time, so Canada would not be considered because it is only 1 summer
Fusion is a type of _____.
chemical reaction
nuclear reaction
physical reaction
Answer:nuclear reaction
Explanation: Nuclear fusion is a type of nuclear reaction where two light nuclei collide together to form a single, heavier nucleus. Fusion results in a release of energy because the mass of the new nucleus is less than the sum of the original masses.
Fusion is the process that powers the sun and the stars. It is the reaction in which two atoms of hydrogen combine together, or fuse, to form an atom of helium. In the process some of the mass of the hydrogen is converted into energy.
cm 5. Express the result of adding 856.6g and 23.86g to the correct number of significant figures.
Answer:
880.5
Explanation:
Express the result of adding 856.6g and 23.86g to the correct number of significant figures.
856.6 +23.86 = 856.6 + 23.9 = 880.5
The result of adding 856.6 g and 23.86 g after rounding off to correct significant figures is 856.6 + 23.9=880.5.
What are significant figures?Significant figures are used for establishment of a number which is presented in the form of digits. These digits give a meaningful representation to the numbers.
The significant figures are the significant digits which convey the meaning according to the accuracy. These provide precision to the numbers and hence are called as significant numbers.There are rules for counting significant figures which are as follows:
1)All non-zero digits are significant .
2)All zeroes which occur between non-zero digits are significant.
3)All zeroes to the left and right of a non-zero digit are not significant.
4) All zeroes on right of decimal are significant if a non-zero number follows them.
5)All zeroes on right side of non-zero digit are significant.
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The table shows the boiling points of fluorine, chlorine and bromine.
Element
Boiling point in °C
Fluorine
-186
Chlorine
-34
Bromine
+59
(c) Explain why the boiling points in the table are low.
Explanation:
the chemicals are group 7 elements and one of their characteristics is that the melting and boiling point increase progressively
1) When a beam of white rays is dispersed by a prism which colour will be refracted to a larger extent?
Explanation:
since diferentes colours of light través at diferentes speeds, the refractiva index is diferentes for each color. The result? that whenthe White light países thought the prism it cover into a red light
How do atomic and molecular interactions explain the properties of matter that we see and feel
The atomic and molecular interactions unveil the bulk properties of matter in our environment by ways of the fact that everything in the whole universe is made of either atoms, molecules or even ions
How matter is made up of atoms and molecules?It has been proven practically everything in the whole universe is matter and everything which interact with matter is also matter. This explains to us the reasons why matter could be atoms, molecules or ions.
That being said, some substances (matter) is made up of atoms of elements, some made up of molecules or atoms and molecules and others ions or both. However, matter is anything which has mass and occupies space.
In conclusion, we can now conclude from the explanation above that the properties of matter are as a result of the interaction which exists between matter at the atomic and molecular level.
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Help pretty please :)
five differences between true solution and false solution
Answer:
k im silly frrr lol have a great day
Which of the following solutions represents a good buffer system? a solution that is 0.10 mol L-1 NaOH and 0.10 mol L-1 KOH a solution that is 0.10 mol L-1 HCl and 0.10 mol L-1 NH4+ a solution that is 0.10 mol L-1 HF and 0.10 mol L-1 CH3COONa a solution that is 0.10 mol L-1 HCl and 0.10 mol L-1 KCl a solution that is 0.10 mol L-1 CH3COOH and 0.10 mol L-1 CH3COOLi
Answer:
chu papi
Explanation:
Identify three ways you could increase the rate of an aspirin tablet dissolving in a glass of water.
Answer:
If you are trying to dissolve a substance, you have three primary avenues to increase the dissolution rate: decreasing the particle size of the solid, increasing the temperature and/or increasing the mixing or stirring rate.
Explanation:
How are sound and light similar? How are they different?
Answer:
Sound requires a medium to move through; light does not.
Sound and light are similar in that both are forms of energy that travel in waves.
Explanation:
Sound and light are similar in that both are forms of energy that travel in waves. They both have properties of wavelength, freqency and amplitude. Sound can only travel through a medium (substance) while light can travel through empty space. Sound is a form of mechanical energy caused by vibrations of matter.
Light waves DO NOT require a medium, they travel fastest in empty space; Sound waves REQUIRE a medium, they travel fastest in dense material like solids. Sound is a longitudinal wave.
The empirical formula of hydrazine, molecular mass 32 grams, is NH2. What is the molecular formula of hydrazine?
A) (NH)4
B) N2H4
C) NH
D) NH2
Answer:
B) N2H4
Explanation:
Dirty water is a _____.
mixture
or
compound ?
Answer: mixture
Explanation: they are heterogeneous mixtures not homogeneous
It's Mixture
Reason:- Dirty water is a mixture of dirt and water. Mixture are made up of 2 or more different substance with different characteristics
The diagram shows the box for elements in the periodic table. What is the atomic number of the element shown. A. 27.0 B. 40.0 C.26 D.13
I think it is B.40.0
Because if you do 27+13=40
It will give 0.
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The atomic number of the shown element Al (Alluminium) is ~
[tex]13[/tex]Explanation:
atomic number = no. of protons = 13
therefore atomic number of aluminium is 13 as given
so option D 13 is correct option .
hope this answer helps you dear! take care
What is the reaction between CCl4 and H2O?
Answer:
At temperatures > 400 °C, CCl4 reacts with H2O over a MgO catalyst to yield HCl and CO2.
Can anyone help me with this question?
sure i can help
so u have to ask someone else
how many moles of s atoms are in 1 mol of CaSO4
I think u asked for the atoms of sulfur? its 4..
Explanation:
calcium = 4
sulfur = 4
oxygen = 4
I hope this is correct
Which one of these is not an important structural feature found by the number of
electron rich regions
Hybridization
Bond Angles
Electronegativity
Electron Geometry
Answer:
Electronnegativity
Explanation:
There are three important structural features: Hybridization, Bond angels, and Electron Geometry.
The not so important structural feature found by the number of electron rich regions is electronegativity. Hence option c is correct.
What are structural feature?Structural feature is defined as the modeled as a directed acyclic graph (DAG), with the variable names as pathways and the variable values as nodes. The study of the construction of biological molecules is known as structural biology. Scientists study molecules in three dimensions using a range of imaging techniques to examine how they are put together, how they work, and how they interact.
Electronegativity is defined as the propensity for atoms involved in covalent bonds to draw the bonding electrons. The negatively charged electrons are drawn to the positively charged protons in the nucleus. The electronegativity or attraction will rise with the number of protons in the nucleus. Therefore, in a row of the periodic table, electronegativity rises from left to right.
Thus, the not so important structural feature found by the number of electron rich regions is electronegativity. Hence option c is correct.
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Which method of separation is used to separate chemicals from blood? Explain with reason.
machine called a centrifuge spins your blood to separate your red blood cells, platelets and plasma. As the blood is separated, the heavier reds cells sink to the bottom and are given back to you.
Air is a mixture of (mostly) oxygen (molecular mass 16) and nitrogen (molecular mass 14) gases. At room temperature, which molecules in this room have more kinetic energy (on average)
The molecules of the two gases will have the same kinetic energy at room temperature.
The average kinetic energy of gaseous molecules can be calculated using the formula:
Kinetic Energy = 3/2RT, where R = constant and T = temperature in Kelvin
This means that the kinetic energy of a gaseous molecule is dependent on the temperature of the molecule only.
In other words, the molecular mass of molecules of gases has no bearing on the kinetic energy of each molecule.
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If 22.5 L of nitrogen at 748 mm Hg are compressed to 725 mm Hg at constant temperature. What is the new volume?
Before
P1 : 748 mmHg
V1 : 22.5 L
After
P2 : 725 mmHg
V2 : ?
748 mmHg / 22.5 L = 725 mmHg / V2
Cross Multiply...
748 mmHgV2 = 16312.5 mmHgL
748 mmHgV2 / 748 mmHg = 16312.5 mmHgL / 748 mmHg
V2 = 21.808155 L
V2 = 21.8 L (sig figs)
What is the volume of 0.1 M HCl required to neutralize 12.0 mL of 0.25M
Ba(OH)2?
Answer:
15ml
4HCl + 2Ba(OH)2 so moles ratio is 4:2
a peanut butter and jelly sandwich contains 9.00 g of fat, 6.00 g of protein, and 25.0 g of carbohydrate. How many calories does this sandwich provide?
Answer:
205 calories.
Explanation:
According to the USDA, "Carbohydrates provide 4 calories per gram, protein provides 4 calories per gram, and fat provides 9 calories per gram." 9 grams of fat at 9 calories per equals 81 calories + 6 grams of protein at 4 calories per gram which equals 24 calories + 25 grams of carbohydrate at 4 calories per gram which is equal to 100 calories.
Total that all up and you get 81 cal + 24 cal + 100 cal=205 calories.
I don't know what kind of course this is for, but if they are incredibly picky, what we refer to as "calories" are actually kilocalories, which are equal to one thousand "real" calories each. However, I'm very confident that the correct answer is 205 calories.
The sandwich will provide 205 calories.
What is calories?A calorie is an energy unit. It's the quantity of heat needed to increase the temperature of one gramme of water by [tex]1^{0} C[/tex] at one atmosphere of pressure.
Its is given that, Fat = 9 g, protein = 6 g, carbohydrate = 25 g.
It is known that, fat contains 9 calories / gram , carbohydrate contains 4 calories / gram and protein contains 4 calories / gram.
Now, adding all terms.
Total calories = (9×9) +(6×4) +(25×4)
= 205 calories.
Therefore, the sandwich will provide a total of 205 calories.
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What is the charge on an electron?
Answer:
Negative Charge
Explanation:
Write a balanced chemical equation for the complete combustion of methanol, ethanol, propanol, butanol and paraffin wax(C25H52). This information will be needed for the experiment. Transfer the answer to the data sheets also. (10 pts)
Answer:
Explanation:
1. Methanol:
CH3OH + O2 ---> CO2 + 2H2O
2. Ethanol:
C2H5OH + 3O2 ----> 2CO2 + 3H2O
3. Propanol:
2C3H7OH + 9O2 ------> 6CO2 + 8H2O
4. Butanol
C4H9OH + 6O2 -------> 4CO2 + 5H2O
5. Paraffin Wax:
C25H52 + 38O2 ----> 25CO2 + 26H2O
Why were people from lower castes drawn to Buddhism?
O The Buddhist belief in equality appealed to them.
O Buddhism allowed people from all castes to participate.
People from the lower castes were born into Buddhism.
O People in the lower castes wanted to choose their own religi
Answer:
During the Maurya empire, the Indian culture and way of life were deeply influenced by Buddhism. Buddhism appealed to people of lower castes because it emphasized individuals' path to enlightenment and salvation, which could be attained in this life.
Explanation:
What statement describes how water is involved in weathering a rock?
Answer:
Water, in either liquid or solid form, is often a key agent of mechanical weathering. For instance, liquid water can seep into cracks and crevices in rock. If temperatures drop low enough, the water will freeze. ... Changes in temperature cause rock to expand (with heat) and contract (with cold).
Answer:
the rock has been rubbed away at for hundreds or thousands of years and the water steady washed the rock away. hope this helped.
What is vibration????
Calculate the mass of butane needed to produce 57.3 g of carbon dioxide.
Answer:
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