Answer:
FALSEExplanation:
A pure substance is a element in it's original state. Two metals mixed together are not pure, if they were separated they would be pure. A rock is not pure since it is a mixture of a lot of materials, that formed that rock. Does this help?
Answer:
False
Explanation:
Pure substance has no mixtures
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
The group in an experiment that is not exposed to the tested variable is called the group
Answer:
yes your answer is correct for this question.
An automobile achieves a gas mileage of 24.5 mi/gal. How many kilometers can it travel on 1.5 L of gasoline?
when sodium metal is treated with water we get gas which is absorbed by palladium metal is ?
that gas is called hydrogen gas
which surface has most friction
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"
Lithium has a 1+ charge, and oxygen has a 2− charge. A Lewis dot diagram should contain one lithium atom and two oxygen atoms to show how these atoms form an ionic bond. true or false
Answer:false
Explanation:
i took the test
molar mass of acetone(CH3COCH3)
Answer:
58.09 g/mol
Explanation:
To find the molar mass, add together the atomic masses of all the elements in the compound.
C - 3 × 12.01 = 36.03
H - 6 × 1.01 = 6.06
O - 16.00
36.03 + 6.06 + 16.00 = 58.09 g/mol
The molar mass of acetone is 58.09 g/mol.
Hope that helps.
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!
A buret is used to dispense standardized NaOH solution. The initial buret reading is 2.73 mL, and after dispensing a known volume of NaOH the buret reading is 15.67 mL. If the concentration of the NaOH is 0.125 M, how many moles of NaOH were dispensed
Answer:
1.62x10⁻³ moles of NaOH were dispensed
Explanation:
Molarity is an unit in chemistry defined as the ratio between moles of solute (In the problem, NaOH), per liter of solution.
The concentration of the solution is 0.125moles per liter. That means 1L of solution has 0.125 moles of NaOH.
The volume you dispensed in the buret was:
15.67mL - 2.73mL =
12.94mL of the 0.125M NaOH are:
12.94mL = 0.01294L * (0.125moles / L) =
1.62x10⁻³ moles of NaOH were dispensedHELP PLEASE !!!!! which of the following molecules has a bent shape
Answer:
A
Explanation:
APEX
The sulfur dichloride has bent shape.
i.e, option A is correct one.
What is shape of the molecule?The three dimension (3D) representation of molecule by excluding lone pair of electron is called shape of the molecule.
The geometry and shape of the molecule is determined by using some theories like valence bond theory, hybridization and VSPER theory.
To learn more about shape of the molecule here.
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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.
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.
Magnesium hydride of mass 0.0348g was dissolve in 15cm cube of water to form a solution .a. write a balanced equation for the reaction
Answer:
It looks like there aren't any great matches for your search
Tip: Try using words that might appear on the page you’re looking for. For example, "cake recipes" instead of "how to make a cake."
What is the percentage of water in the following compound? Answer using three significant figures. Sodium carbonate decahydrate, Na2CO3 • 10H2O % by mass H2O
Answer:
63% (Or any value you get that can round to this percentage)
Explanation:
First, you will need to collect various values such as molar mass to start off this question.
The molar mass of sodium carbonate is 106g per mole. You can find this value with your provided molar mass sheet within your respective textbook or by simply searching this value up on the Internet. The coefficient of sodium carbonate is 1 (since there is no value shown for the coefficient), so the mass of sodium carbonate will be 106g.
The molar mass of water is 18.01g per mole, so this means that the mass of water here will be 180.1g since the coefficient of H2O is 10, and 10*18.01g/mole is 180.1g.
Now, you will need to add the masses of both substances together.
106g + 180.1g = 286.1g
The mass of water is 180.1g so...
180.1g / 286.1g = 0.6295
Because we need a percentage for the answer, you will need to convert the decimal into a percentage.
0.6295 => 63% (The answer!!!)
Answer:
63.0% on edge
Explanation:
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 :)
What defines the mass number of an isotope? the sum of the neutrons and protons the sum of the neutrons and electrons the number of neutrons the number of protons
Answer:
The mass number of an isotope is the sum of neutrons and protons.
Explanation:
In any elemental isotope, the only things that will affect molar mass and mass number is the number of protons and neutrons. Electrons are not counted because we usually assume they are equal to the amount of protons and have no weight.
Protons are what gives the element its atomic number and the neutrons determine the type of isotope it is within the element.
For instance:
There can be a regular Carbon - 12
But there are isotopes like Carbon - 13 and Carbon - 14.
*The number of protons stays the same but the number of neutrons are different
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 statement describes all chemical changes, but not all physical changes? Bubbles are produced. A new substance forms. Phase changes occur. A color change occurs.
Answer:
A new substance forms
Explanation:
A chemical change is a change in matter that results in a change in its identity and properties. Therefore, a new substance forms.
Answer:
b
Explanation:
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
Which statement is most likely true?
Ernest Rutherford’s experiment led to the nuclear model of the atom.
Ernest Rutherford’s experiment established the plum pudding model of the atom.
Robert Millikan’s postulates form the most accepted theory for the atomic structure.
Robert Millikan’s results had little impact on determining of the charge of an electron.
Answer : Option A) Ernest Rutherford’s experiment led to the nuclear model of the atom.
Answer:
A: Ernest Rutherford’s experiment led to the nuclear model of the atom.
Explanation:
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.
To find density of an object what 2 things are needed?
Answer: mass and volume
Explanation:
Divide the mass by the volume in order to get an object's Density.
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.
Select the correct answer. Which factor causes water to form small drops on a waxy surface? A. van der Waals forces B. hydrogen bonding C. London dispersion forces D. ionic bonding
Answer:
B. hydrogen bonding
Explanation:
Waxy surfaces are non-polar while also water is polar. There is a difference in electronegativity between the atoms O and H, in which O is more electronegative than H. Such a difference in electronegativity causes the two covalent O-H bonds to become polar in water, where O atom has a partial negative charge, and the H atom has a partial positive charge.
Therefore from the above explanation the correct answer is B
11. Group 17 elements are called.
there is no group 17
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
name the harmful by products formed by the burning of diesel and coal
Burning of diesel and coal produces a suffocating and corrosive gas-Sulphur dioxide gas, and Petrol engines give off gaseous oxides of nitrogen. Oxides of these sulphur and nitrogen dissolves in rain water and causes Acid Rain
Answer:
Burning of coal and diesel release sulphur dioxide gas. It is an extremely suffocating and corrosive gas. Sulphur dioxide and nitrogen oxide dissolve in rain water to form acid. Such rain is called acid rain.
Explanation:
what are 2 differences between the atomic theory described by Thompson and that described by Rutherford ?
Explanation:
1)Thomson model, electrons are embedded in positive charged solid material(nucleus)
Rutherford model, electrons surround the positive charged nucleus
2)Thomson, does not explain about atomic nucleus
Rutherford, explains in detail about nucleus
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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