Answer:
The track of the Moon's shadow across Earth's surface is called the Path of Totality. This path is typically 16,000 kilometers (about 10,000 miles) long but only 160 kilometers (100 miles) or so wide. In order to see the Sun totally eclipsed by the Moon you must be in the path of totality.
Explanation:
PLEASE HELP : what are 2 chemical and physical properties of a base and two chemical and physical properties of an acid?
Answer:
physical: color, appearance chemical: reactivity, flammability
what is meant by the term chemical reaction
Answer:
[tex] \huge{ \underline{ \underline { \bold{ \sf{ \orange{See \: below}}}}}}[/tex]Explanation:
▪️[tex] \underline{ \bold{ \sf{ \blue{Chemical \: reaction}}}}[/tex]
⇒The composition , decomposition or displacement of molecules of matter during chemical change is called chemical reaction.
▪️[tex] \underline{ \bold{ \sf{ \purple{ \: Further \: more \: explanation}}}}[/tex]
Various conditions bring about these changes. The chemical reactions are represented by chemicalequation. The compounds or elements that take part in chemical reaction are called reactant. They are written at the left side of an arrow that represent a change while the compound or elements that formed after the chemical change are called product. They are written at the right side of the arrow.
▪️[tex] \underline{ \bold{ \sf{ \purple{For \: example}}}}[/tex]
When nitrogen reacts with hydrogen to form ammonia :
Nitrogen + Hydrogen ⇒ Ammonia
N₂ + 3H₂ ⇒ 2NH₃
Presentation of a chemical reaction in the form of equation is called chemical equation . Chemical equation may be word equations or formula equations.
Hope I helped!
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Review
1 Why is gold considered to be valuable?
2. Who owned the gold mines during the ancient Egyptian and Roman civilizations?
3. What is the elixir of life?
4. What contributions to modern chemistry were made by the alchemists?
Answer:
1. Gold is valuable because of its high quality physical and chemical properties
2. The gold mines where the state's property in both Egyptian and Roman civilizations
3. The elixir of life is akin to the philosopher stone. It is a chemical portion that when drank, grants eternal life
4. The contribution of alchemists to modern chemistry, includes the formulation of the first ideological periodic table, the distillation process, metalworking, gunpowder, glass, ink, paints, cosmetics and many other innovations
Explanation:
when sodium metal is treated with water we get gas which is absorbed by palladium metal is ?
that gas is called hydrogen gas
which unit of measurement is used in the metric system miles kilograms gallons tons
Answer:
Kilograms
Explanation:
The metric system denotes their measurements with prefixes (kilo)
I need help with number 3 please look at the picture!!
Answer:
Answer is (a)
Explanation:
Which equation describes the mass of an object in relation to its volume and density? a. m=DV b. m=D×V c. m=D+V d. m=VD
Answer:
B
Explanation:
the formula is d=m/v
both sides xV
dv=m
The equation describes the mass of an object in relation to its volume and density is m=D×V. option B is correct.
What is density?
The density of a substance is the mass of per unit volume of a substance or any object and the density will be equal to the division of mass of the substance to the volume of the substance and its SI unit will be cubic centimeter.
The equation of mass can be calculated by the help of the formula of density too. so, the mass will be the multiplication of the density of a substance and the volume of the substance and the unit will be kilogram.
Therefore, equation describes the mass of an object in relation to its volume and density is m=D×V. option B is correct.
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as a result of the law of conversation of mass a balanced chemical equation must
The scientific method is an order of steps that is followed and the first step of scientific inquiry is often ____________________________________
Group of answer choices
Design the experiment
Interpret data
develop a hypothesis
Developing the problem
Answer:
Developing the problem
Explanation:
In order to have an experiment or to make the experiment's data useful, you must first find a problem to solve.
Determine the density of a liquid from the following data: Mass of the
graduated cylinder: 33.79 g. Mass of the cylinder and liquid: 40.14 g
Volume of liquid: 13.3 mL
Answer:0.477 g/ml
Explanation:
Density=(40.14-33.79)/13.3 ml
Density=6.35/13.3
Density=0.477 g/ml
which two quantities are used to predict gravitational force according to newton's law of universal gravitation
Answer:
Observe how the force of gravity is directly proportional to the product of the two masses and inversely proportional to the square of the distance of separation.
Explanation:
I think im not sure
At STP, how many moles are in 21.5 L CH4?
Answer:
0.96 mole of CH4.
Explanation:
From a background knowledge of gas laws, we understood that 1 mole of a gas occupy 22.4 L at STP. This implies that 1 mole of CH4 also occupy 22.4 L at STP.
Now, we shall determine the number of mole of CH4 that will occupy 21.5 L at STP. This is illustrated below:
1 mole of CH4 occupied 22.4 L at STP.
Therefore, Xmol of CH4 will occupy 21.5 L at STP. i.e
Xmol of CH4 = (1 × 21.5)/22.4
Xmol of CH4 = 0.96 mole
Therefore, 0.96 mole of CH4 will occupy 21.5 L at STP.
Convert 64,567 milliliters into nanometers
Answer:
64567000000 nanolitres
Explanation:
Base 10 decimal system: 1 milli = 1000000 nano
We simply multiply 64,567 millilitres by 1000000 to get our number in nanolitres:
64567(1000000) = 64567000000 nanolitres
Recording a change in the color of a substance is an example of collecting __________ data.
Answer:
Qualitative
Explanation:
Recording a change in the color of a substance is an example of collecting qualitative data.
Data generally refer to information collected or recorded through observations. There are different types of data:
Quantitative data: data that can be quantified/measured. Examples include; height, number of cars, intelligence quotient, etc.Qualitative data: Data that cannot be quantified but categorized or ranked. E. g. beauty, color, etc.Hence, recording a change in the color of a substance can be classified as collecting qualitative data.
3. An irregularly shaped stone was lowered into a graduated cylinder holding a volume
of water equal to 2.0 ml. The height of the water rose to 7.0 ml. If the mass of the
stone was 25 g, what was its density?
Answer:
Hey there!
The volume rose by 5 ml, and that means the stone has a volume of 5 ml. Thus, the stone has a density of 25/5, or 5 g/cm^3.
Let me know if this helps :)
4. "The art of oration (speaking) is being
replaced by personal broadcasting." What does
this mean?
Answer:
People show more interest in personal broadcasting.
Explanation:
The art of oration (speaking) is being replaced by personal broadcasting mean now people used webcam or camcorder for creating its own content and transmit it to other people through internet. Personal broadcasting provides audio and video to the individual that make it more interesting as compared to oration. People show more interest in personal broadcasting as compared to oration so that's why oration is replaced by personal broadcasting.
what is the importance of cell membrane
Answer:
the membrane forms an outer boundary of the cell and, as such, holds the cell together. The membrane is also pliable, which means it can move and flex in response to the surrounding environment. The fluid nature of the membrane is important because it allows the cell to survive in various environments.
Explanation:
understand yourself!
How might a museum curator be involved in science?
Answer and explanation:
A museum curator is most likely an art conservationist. They would have to determine the age an art piece was developed and ways to preserve older artefacts.
These processes would require the use of chemicals and physical tests, and also research laboratories.
I hope this answer is helpful and clear.
Briefly define correlation
Answer:
Correlation means association - more precisely it is a measure of the extent to which two variables are related. There are three possible results of a correlational study: a positive correlation, a negative correlation, and no correlation.
Explanation:
PLS MARK BRAINLIEST
Answer:
a mutual relationship or connection between two or more things.
Explanation:
"research showed a clear correlation between recession and levels of property crime"
1. The volume of a given mass of gas is 720 ml at 15°C. Assuming
constant pressure, at what temperature will its volume be 960 ml?
2. A sample of gas is found to occupy a volume of 900 cm3 at 270
°C. Calculate the temperature at which it will occupy a volume of
300 cm3, provided the pressure is kept constant.
please mark my answer brainliest...
condition...pressure remains constant.
for 720 ml temp is 15°...so for 960ml temp will be 15/720×960=20°...(.answer for 1st part...)for 900cmcube temp is 270°C...so for300cmcube temp will be 270/900×300=90°....(answer for 2nd part)...I hope it helps the dear students...and if it is then let me know through ur comments...and please mark my answer as brainliest...plz...1. The temperature at which the volume of gas has been 960 ml is [tex]\rm \bold{19.99\;^\circ C}[/tex].
2. The temperature at which the volume of gas has been [tex]\rm 300\;cm^3[/tex] is [tex]\rm \bold{90^\circ C}[/tex].
1. The gas has been assumed to be an ideal gas. For an ideal gas, the relationship between temperature and volume at constant pressure has been given as:
[tex]\dfrac{V1}{T1}=\dfrac{V2}{T2}[/tex]
Where, the initial volume, [tex]V1=720\;\text {ml}[/tex]
The final volume, [tex]V2=960\;\text {ml}[/tex]
The initial temperature, [tex]T1=15\;^\circ \text C[/tex]
Substituting the values, the final temperature, T2 can be given as:
[tex]\rm \dfrac{720\;ml}{15\;^\circ C}=\dfrac{960\;ml}{\textit{T}2} \\\textit T2=\dfrac{15\;^\circ C}{720\;ml}\;\times\;960\;ml\\\textit T2=19.99\;^\circ C[/tex]
The temperature at which the volume of gas has been 960 ml is [tex]\rm \bold{19.99\;^\circ C}[/tex].
2. The temperature for gas to occupy [tex]\rm 300\;cm^3[/tex] has been given as:
Where, the initial volume, [tex]V1=900\;\rm{cm^3}[/tex]
The final volume, [tex]V2=300\;\rm {cm^3}[/tex]
The initial temperature, [tex]T1=270\;^\circ \text C[/tex]
Substituting the values, the final temperature, T2 can be given as:
[tex]\rm \dfrac{900\;cm^3}{270\;^\circ C}=\dfrac{300\;cm^3}{\textit{T}2} \\\textit T2=\dfrac{270\;^\circ C}{900\;cm^3}\;\times\;300\;cm^3\\\textit T2=90\;^\circ C[/tex]
The temperature at which the volume of gas has been [tex]\rm 300\;cm^3[/tex] is [tex]\rm \bold{90^\circ C}[/tex].
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11. Group 17 elements are called.
there is no group 17
Which bond is intermediate in terms of strength? why is it weaker than the strongest? ap bio?
Answer:
Covalent bonds are intermediate in strength and weaker than ionic bonds
Explanation:
Because ionic bonds tend to form a rigid lattice structure that make them more stronger and difficult to remove electrons from them
Question 2 (4 points)
(01.06 LC)
Air is an example of a mixture because the elements and compounds that make up air retain their individual properties. (4 points)
True
Or False
Answer:
True
Explanation:
They do retain their individual properties.
at 25*C, the vapor pressure of pure water is 23.8 torr. a solution is prepared by dissolving 0.30 mol Na2SO4 in 8.0 moles of water. what is the vapor pressure of this solution at 25*C
Answer:
Vapor pressure of the solution is 22.9 torr at 25°C
Explanation:
When a non volatile solute is added to a pure solvent, the vapour pressure of the mixture decrease regard to the pure solvent following the equation (Raoult's law):
[tex]P_{solution}=X_{solvent}.P^0_{solvent}[/tex]
Where vapour pressure of the pure solvent (Water) is 23.8torr at 25°C.
Mole fraction of water is the ratio between moles of water and total moles in solution. The solution has a mole fraction of water of:
[tex]X_{water}=\frac{8.0Moles_{water}}{0.30mol_{Na_2SO_4}+8.0mol_{water}} = 0.9639[/tex]
Replacing in Raoult's law:
[tex]P_{solution}=0.9639*23.8torr[/tex]
Vapor pressure of the solution is 22.9 torr at 25°CQuestion 5
5. CFC's break down
Ozone
carbon dioxide
Oxgygen
nitrogen
Answer:
ozone. CFCs drift slowly upward to the stratosphere, where they are broken up by ultraviolet radiation, releasing chlorine atoms, which are able to destroy ozone molecules.
Answer:
C: Oxygen
Explanation:
When they are exposed to strong ultraviolet light, CFCs finally break down to release lone chlorine atoms with an unpaired electron. These chlorine atoms are highly unstable and react with ozone to break it down into oxygen through a type of chain reaction.
Chemistry course is intended for what type of students?
Answer:
Chemistry course is intended for students who did not take chemistry in high school or who struggled with high school chemistry.
Explanation:
246.24+238.278+98.3
Calculate to the appropriate number of significant figures
Answer:
The correct answer is 582.8.
Explanation:
To solve this problem, we must remember the rules for significant figures for addition. Recall that the answer should have the same number of decimal places as the term with the least number of decimal places that we are adding. In this case, we can see that out of our three terms, 98.3 has the least number of decimal places. This lets us know that our answer should be rounded to the tenths place.
With this in mind, we can compute the addition.
246.24 + 238.278 + 98.3
= 582.818 (unrounded value)
However, we stated that our answer should be rounded to the tenths place.
Therefore, our answer is 582.8.
Hope this helps!
What is dimensional analysis? How is it used?
Answer:
dimensional analysis is the way of converting different units. when you add two physical quantities or equate them they must be in same units.
uses:
to check the correctness of a physical formula
to convert the value from the one system to another.
to form a relationship between different physical quantities
A pharmaceutical company wanted to test a new drug developed to lessen the effects of
the common cold. To test this drug, scientists tested fifty volunteers, each of whom
was suffering the effects of a cold. Twenty-five of the people were given the drug.
while the other twenty-five were given a placebo, a sugar pill. None of the participants
knew who was taking which pill. All participants received a pill at 8:00 a.m. daily for the
first three days of the study. All participants lived in the same environment, with the
same climate, eating the same diet, and having the same level of activity. The severity
of the cold, hence the effectiveness of the pill, was determined by the number of
tissues each person used within a 24-hour period. At the end of a 7-day period it was
concluded that those with the sugar pill used the same amount of tissues as those who
had taken the new wonder drug. The executive committee decided to produce the drug
anyway thinking that the public would do anything to relieve the symptoms of a cold.
Answer:
This question is incomplete; the remaining part of the question asks to
State the problem, the hypothesis, independent variable, dependent variable, control group, constants, conclusion and if the data is qualitative or quantitative
Please find the answer to each of the above mentioned below
Explanation:
1. The problem of this experiment conducted by the pharmaceutical company is to test whether a newly developed drug will lessening common cold effects in people.
2. The hypothesis is testable explanation given to solve a problem. In this experiment, the hypothesis will be: IF the volunteers took the newly produced drug, THEN the severity of the cold will be reduced.
3. Independent variable is the variable that is manipulated or changed in an experiment. The independent variable in this experiment is DRUG because it is what is changed by the pharmaceutical company.
4. The dependent variable is the variable that is measured or tested in an experiment. It is what responds to change in the independent variable. In this experiment, the dependent variable is the EFFECT OF THE COMMON COLD/NUMBER OF TISSUES USED
5. The control group in an experiment is the group that is not administered the experimental treatment. In this case, the twenty-five people that were given a placebo, a sugar pill is the CONTROL GROUP.
6. Constants or Control variables are the variables that the experimenter keeps constant or unchanged throughout the experiment. In this case, the constants are the same environment, the same climate, eating the same diet, and the same level of activity.
7. The CONCLUSION of this experiment is that the sugar pill used the same amount of tissues as those who had taken the new wonder drug. This means that both the drug and sugar pill have the same level of effectiveness. Hence, the hypothesis is DISPROVED because the drug had no improved effect on the people.
8. A quantitative data is one which involves the use of values and numbers. In this experiment, the effectiveness of the pill was determined by the number of tissues used, hence, the data is QUANTITATIVE.
The reaction between between common salt and concentrated tetraoxosulphate(vi) acid will liberate
A. sulphur (iv) oxide
B. oxygen and chloride
C. Hydrogen chloride gas
D. Hydrogen sulphide gas
most prolly option D
Explanation:
NaCl + H2SO4 -> Na2SO4 + HCl[g]
The reaction between between common salt and concentrated tetraoxosulphate(vi) acid will liberate Hydrogen chloride gas .
What is a Chemical reaction?
This is the type of reaction in which two or more elements/compounds react together to form a new substance.
The reaction between common salt and concentrated tetraoxosulphate(vi) acid can be seen below:
NaCl + H2SO4 ⇒ Na2SO4 + HCl(g)
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