Answer:
3- True or false: it is OK to leave your bags in the aisle
4- True or false: horseplay is fine before or after the lab
5- True or false: you do not need goggles or gloves for lab
6- True or false: you do not need to wash your hands after lab
7- True or false: it is OK to eat and drink in a lab class
8- True or false: it is OK to pour chemicals back into the bottle it came from
9-True or false: microscopes can be handled with one hand only
10-True or false: you do not need to read the instructions before lab
11-True or false: respect safety rules and guidelines
Explanation:
I bolded the ones that it's supposed to be. You're teacher gave you a lot of false's though
In the 1800s, one of the statements in john dalton's atomic theory was that atoms are indivisible. later experimental evidence led to the discovery of subatomic particles such as neutrons, electrons, and protons. what happened to the indivisible atom part of dalton's atomic theory, and why? the entire theory was discarded because dalton's scientific reputation was ruined once new evidence invalidated part of his theory. the indivisible atom part of the theory was discarded because consensus of data must exist for theories to be valid. the theory remained unchanged because dalton was correct regarding all other statements within the accepted scientific theory. the theory remained unchanged because new data is discarded if it doesn't fit within the accepted theory.
In 1800s, the john Dalton's atomic theory was that atoms are indivisible. later on , The indivisible atom part of the theory was discarded because consensus of data must exist for theories to be valid.
The Dalton's theory has some postulate which states that :
1) The atoms are the smallest form of matter and are the indivisible.
2) Each atom of same element have same and different atoms must be different types of element.
3) Atoms can not be created nor be destroyed but can be mix match.
4) Compound form from different elements combine in specific ratio.
now, the first postulate , has already been proving wrong by experiments like Rutherford's gold foil experiment and Thomson's discovery of electron.
Science is based on experiments and testings. in case of Dalton's atomic theory . it was not completely wrong but the only part that atom is indivisible was wrong.
therefore only this part was discarded that : The indivisible atom part of the theory was discarded because consensus of data must exist for theories to be valid.
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A sample of gallium exists as two isotopes, 69 Ga, relative abundance of 61.2%, and 71 Ga, relative abundance of 38.8%. Calculate the relative atomic mass of gallium. Pls, help me!!!
The relative atomic mass of gallium, given that it exists as two isotopes is 69.776 amu
From the question given above, the following data were obtained:
Mass of isotope A = 69Abundance of A (A%) = 61.2%Mass of isotope B = 71 Abundance of B (B%) = 38.8%Relative atomic mass =?How to determine the relative atomic massThe relative atomic mass of the isotope can be obtained as illustrated below:
Relative atomic mass = [(Mass of A × A%) / 100] + [(Mass of B × B%) / 100]
Relative atomic mass = [(69 × 61.2) / 100] + [(71 × 38.8) / 100]
Relative atomic mass = 42.228 + 27.548
Relative atomic mass = 69.776 amu
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check my answers! please hurry ive been working on this test for over 2 hrs lol
Question 1: The periodic table is arranged by various patterns. Is there a pattern with regard to ionic charge? In three to five sentences, explain your reasoning and provide specific examples.
Question 1 Answer: Negative ions increase in magnitude from right to left, whereas positive ions increase in magnitude from left to right. This is due to the fact that the left side of the periodic tale contains metals whereas the right side does not. As negative-charged electrons are always produced by metals, the element will become more positive when they are lost.
Question 2: Moving from the element with atomic number 10 to atomic number 11 on the periodic table, there is a change in reactivity. In three to five sentences, identify the direction of the change, and give two reasons for the change.
Question 2 Answer: The atomic number of sodium is 11, while neon is 10. Since neon has an outer shell made entirely of electrons, it doesn't interact with the other elements. The extra electron in sodium is located in the outer shell and there is one extra proton as well. By either losing one electron or gaining seven more, it might fill that shell. Since it will start losing that electron, sodium is a much more reactive element then neon.
Positive ions grow in magnitude from left to right, while negative ions grow in magnitude from right to left.
What are ions?Any atom or collection of atoms with one or more positive or negative electrical charges is known as an ion.
The periodic table shows that there are more valence electrons on the right than the left. The maximum amount of ionic charge that an element can hold fluctuates as the number of valence electrons rises.
Second, metals on the periodic table's left side primarily produce positively charged ions. These ions get stronger over time, increasing in size.
The negative charges on the ions that non metals on the right side of the periodic table produce have a diminishing magnitude over time.
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When incorporated into a polypeptide chain not at the n or c terminus, _______ would make the charge of the polypeptide more positive.
When incorporated into a polypeptide chain not at the n or c terminus, Arginine would make the charge of the polypeptide more positive.
Do humans require arginine?Because arginine is an essential amino acid for young organisms' optimal growth and development, it must be provided in the diet. Arginine is a conditionally essential amino acid for adults, particularly in conditions such as trauma, burn injury, small-bowel resection, and renal failure.L-arginine is an amino acid that aids in protein synthesis in the body. It also causes nitric oxide to be released into the bloodstream. According to a 2016 review, nitric oxide acts to widen blood vessels in the bloodstream, which may help with certain circulatory conditions. The substance also stimulates insulin release in the body.Because L-arginine relaxes blood vessels, it may benefit men suffering from erectile dysfunction (ED) caused by poor blood flow. It may improve the efficacy of medications such as sildenafil (Viagra). Taking L-arginine with ED medication may cause blood pressure to drop too low.To learn more about Arginine refer to
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The density of enthanol is 0.789 g/ml at 20 c what is the mass of a sample of ethanol at this temperature that has a volume of 175.0 ml?
The mass of a sample of ethanol at 20°C is with volume 175.0 mL and density 0.789 g/mL is 138.075 g.
Density is defined as the mass of a substance per unit volume. It is denoted by ρ.
The mass of a substance when the density and volume is given can be found by using the formula -
Density = mass
volume
ρ = m
v
Given data -
volume of ethanol = 175.0 mL
density = 0.789 g/mL
So, the mass is -
Mass = density x volume
mass = 0.789 g/mL x 175.0 mL
mass = 138.075 g
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Which of the following does not describe a physical property of iron?
A
B
C
D
Iron is silvery-white or gray in color.
Iron has a boiling point of about 3,000°C.
Iron is a magnetic element.
Iron and sulfur react to form iron sulfide.
BACK
Answer:
D: Iron and sulfur react to form iron sulfide.
Explanation:
To make iron sulfide you need to combined Iron and Sulfur atoms, producing a chemical reaction.
The four essential elements for life are _______. a. carbon, hydrogen, oxygen and nitrogen b. carbon, hydrogen, oxygen and iron c. carbon, nitrogen, oxygen and magnesium d. iron, nitrogen, oxygen and magnesium please select the best answer from the choices provided a b c d
Explanation:
it suppose to be oxygen hydrogen nitrogen and phosphorus
its A fr fr ong like this is fax
How many moles of atoms are in 50 atoms Ba
moles of atoms in 50 atoms of barium are 301.15 × 10^23
We may determine how many chemicals or particles are included in one mole using Avogadro's number.Chemistry's fundamental building block is an atom. It is the smallest fraction of matter into which electrically charged particles cannot be released. It is also the smallest piece of substance with chemical element-like characteristics.A mole of any substance is equal to 6.023 x 10^23, or Avogadro's number. Additionally, it is employed to express concentrations in terms of moles per litre or molecular weight.The number of atoms in exactly 12 grammes of pure carbon-12 is the value of a mole.Chemical element barium has the chemical symbol Ba and atomic number 56. In group 2, it is the fifth element.1 mole of substance = 6.023 x 10^23
so in 50 atoms of Ba = 50 × 6.023 × 10^23
= 301.15 × 10^23
Therefore, moles in 50 atoms of Ba is 301.15 × 10^23.
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Which sentence from the article BEST supports the idea that not all liquids evaporate at the same temperature?
A
The temperature at which a liquid turns into a gas is called its boiling point.
B
That same temperature can be considered the melting point if the temperature is increasing and causes a solid to become a liquid.
C
For example, liquid water turns to a solid form — ice — when it is cooled to 32 degrees Fahrenheit (0 degrees Celsius).
D
Different types of matter have different boiling, melting and freezing points.
The sentence which BEST supports the idea that not all liquids evaporate at the same temperature is: Different types of matter have different boiling, melting and freezing points; option D
What is evaporation?Evaporation is the process by which a liquid substance spontaneously changes to liquid.
Evaporation of a liquid is affected by the following factors:
the nature of the liquidthe boiling point of the liquidthe presence of windrelative humiditySubstances with low boiling point usually evaporate at a faster rate tan substances with higher boiling points.
However, due to the nature of various substances, different types of matter have different boiling, melting and freezing points. Thus, not all liquids evaporate at the same temperature.
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The usual soda pop can contains 360 mL. How many such cans could be filled from one 2.0 L bottle?
If there is a usual soda pop that contains 360 mL then the number of cans that can be filled from 2.0 L bottle are 5.5 pop cans.
Amount present in one soda can = 360 mL
Total amount present = 2.0 L
Convert 2.0 L into mL
1 L = 1000 mL
2.0 L = 2.0 x 1000 mL
= 2000 mL
So, the total amount = 2000 mL
Number of can using 360 mL = 1
The number of soda pop cans that can be filled using 2000 mL
= 2000 x (1/360)
= 2000/360 = 5.5 pop cans
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The km of an enzyme is 5. 0 mm. Calculate the substrate concentration when this enzyme operates at one‑quarter of its maximum rate.
The substrate concentration of this enzyme operates at one‑quarter of its maximum rate is = 0.333.
What is the relationship between Km and substrate concentration?In practice, Km is the concentration of substrate that allows the enzyme to achieve half Vmax. An enzyme with a high Km has a low affinity for its substrate and requires a higher concentration of substrate to achieve Vmax." Because Km is a constant, increasing the substrate concentration has no effect on it. The substrate concentration Km corresponds to the substrate concentration at which the reaction rate of the enzyme-catalyzed reaction is half of the maximum reaction rate Vmax.Steps of the equation :
[tex]V_{0} = \frac{V_{max}[5] }{[5]+Km}[/tex]
Fraction of [tex]V_{max}[/tex] :
[tex]\frac{V_{0} }{V_{max}} = \frac{[5]}{[5] + Km} = \frac{0.5 Km}{1.50 + Km} = 0.333[/tex]
The substrate concentration of this enzyme operates at one‑quarter of its maximum rate is = 0.333.
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How to convert a velocity of 2.03x10 to the -9 cm/min. to m/s.
The velocity in m/s will be 0.03 x 10^-11 m/s
2.03x10^-9 cm/min x 1 m/100 cm x 1 min/60 sec =
0.03 x 10^-11 m/s
What is Velocity ?As a vector measurement of the rate and direction of motion, velocity is defined. Velocity can be defined as the rate of movement in one direction. Velocity may be used to calculate the speed of a car moving north on a major motorway and the speed of a rocket launching into space.
There are several various forms of velocity, including uniform, variable, average, and instantaneous.According to the equation v = s/t, velocity (v) is a vector quantity that quantifies displacement (or change in position, s), over change in time (t).Learn more about Velocity here:
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Marco put a pot of water on to boil eggs. after a few minutes all the water was This is an example of _____.
Multiple choice question.
A)
condensation
B)
deposition
C)
sublimation
D)
vaporization
Answer:
D) vaporizationExplanation:
Marco put a pot of water on to boil eggs. after a few minutes all the water was dry
This is an example of vaporization.hopefully this helps you!
What is the mass of an object when the triple beam balance reads 100.00 g, 20.00 g, 0.20 g, and 0.05 g?
What is true about these two pictures? PLS HELP ME
Both A and B are molecules.
Both A and B are elements.
A is a compound, but B is an element.
A is an element, but B is a compound.
Answer:
Both A and B are molecules.
When a student is recording descriptions such as the color and shape of a rock specimen, the student is making a(n) __________.
A)
hypothesis
B)
inference
C)
theory
D)
qualitative observation
E)
quantitative observation
When a student is recording descriptions such as the color and shape of a rock specimen, the student is making a qualitative observation.
To geologists, rocks are natural substances made up of solid crystals of various minerals fused together into a solid mass. Minerals may or may not be formed at the same time. The point is that a natural process tied them all together. Weathering is a major deformation of rocks.
Heat and pressure form common rocks, but dramatic changes in their shape correspond to weathering because weathering breaks rocks from large structures into small mineral particles. These white bands or streaks, often called veins, are quartz or calcite. Quartz-filled crevices and fissures in the rock. Calcite was formed by the precipitation of calcium carbonate from water flowing over rocks.
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Answer:
Qualitative observation
Explanation:
There is a common difference between qualitative and quantitative observation
Quantity related observation such as mass of rock comes under quantitative observationBut here the color and shape is observed so it's qualitative observation
option D
How many molecules of water are required for the hydrolyzation of a polymer that is 22 monomer-long cellulose molecule?.
21 molecules of water are required for the hydrolyzation of a polymer that is 22 monomer-long cellulose molecule.
For hydrolyzation of 22 monomer-long cellulose molecule, 21 molecules of water are required. As for three monomer polymer there are 2 bonds so we require two water molecules.
The process of hydrolyzation is a step-by-step reaction in which-
The first step is the condensation of one glucose molecule to produce a 2 monomer-long chain, which releases one molecule of water.
The second step is reaction between the 2 monomer-long chain with other glucose molecule, which release an extra molecule of water.
These steps are repeated until 21 condensation reactions occurs, to give 22 monomer-long cellulose molecule.
The OH group from first monomer of the glucose unit and H group from second monomer is removed in the form of water molecules, when polymer bond is formed.
The reaction is known as the condensation reaction. It is referred to as the loss of water in a chemical reaction.
Therefore, 22 monomer long cellulose molecule indicates 21 reactions of condensation with release of 21 molecules of water.
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consider the following questions about polyprotic acids and determine if each statement is true or false. for polyprotic acids ka1 is typically much smaller than ka2 for most polyprotic acids, each proton dissociation can be looked at separately for most polyprotic acids all ka values must be considered to determine the ph of the solution
For polyprotic acid ka1 is greater than ka2 , each proton dissociation can be looked at sepatertely and all the ka values must be not considered to determine the PH.
Polyprotic acids is a substance capable of donating more than one proton. Di protic and tri protic are the one capable of donating two o three proton,respectively.
For polyprotic acid ka1 is smaller than ka2 is not correct. for polyprotic acid ka1 is greater than ka2 as they have tendency to give off more than one H+ ion.
The proton dissociation can be looked at separately for most polyprotic acid is correct . each proton dissociation can be look at separately.
All ka values must be consider to determine the PH of solution is not correct.we can use ka1 as an approx because ka2 is considerably smaller no.
Thus, for polyprotic acid ka1 is greater than ka2, each proton dissociation can be looked at separately and all the [tex]K{a}[/tex] values must not be considered to determine the PH.
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19. When are ionic bonds formed.
When electrons are transferred between two atoms.
O When covalent compounds are melted.
When electrons are shared between two atoms.
When ionic compounds are melted.
Answer:
when electrons are shared between two atoms
Explanation:
Ionic bonding is when two elements gain and lose electrons and protons until their last shell is full
Which blood vessels serve the body cells?
Veins
Arteries
Capillaries
Plasma
Answer: The blood vessels that serve the body cells is Capillaries.
Explanation: The tiniest blood vessels in the body, capillaries link the tiniest arteries to the tiniest veins. Because they provide oxygen and nourishment to every cell in the body and remove carbon dioxide so that it may be expelled, these capillaries are frequently referred to as the "microcirculation."
The hydrogen ion concentration of a vinegar solution is 0.00010 m. how is this concentration written in scientific notation? 1.0 times. 10â€""5 m 1.0 times. 10â€""4 m 1.0 times. 104 m 1.0 times. 105 m
1.0 ×[tex]10^{-4}[/tex] this is the concentration scientific notation.
What is the significance of scientific notation?The main reason for converting numbers to scientific notation is to make calculations involving unusually large or small numbers easier. Because zeros are no longer used to set the decimal point, all digits in a scientific notation number are significant, as demonstrated by the examples below.The primary reason for the importance of scientific notation is that it allows us to convert very large or very small numbers into much more manageable sizes. It is much easier to work with these numbers when they are written in scientific notation.In this problem, there are two significant figures. The final answer should also have two significant figures.
All scientific notation should have a non-zero number, followed by a decimal point to it's right, followed by remaining significant figures after that. The first non-zero number is 1, so the decimal point should follow the 1.
Moving the decimal to the right decreases the power of ten. The current number can be expressed as
0.00010×[tex]10^{0}[/tex]
00.0010×[tex]10^{-1}[/tex]
000.010×[tex]10^{-2}[/tex]
0000.10×[tex]10^{-3}[/tex]
00001.0×[tex]10^{-4}[/tex]
You can write the final answer by ignoring the initial zeros
1.0×[tex]10^{-4}[/tex]
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Which quantity expresses the sum of 22.1 g + 375.66 g + 5400.132 g to the correct number of
significant figures?
1) 5800 g
2) 5798 g
3) 5797.9 g
4) 5797.892 g
The quantity that expresses the sum of the given parameters is =5797.9g. That is option 3.
Calculation of the give figureSummation is the addition of figures to achieve a significant figure.
Significant figures on the other hand is the representation of digits in numbers that are reliable and accurate.
The given figures include the following:
= 22.1 g + 375.66 g + 5400.132 g
= 5797.892
= 5797.9g
5797.9g is the correct significant figure because the digit at the second decimal place is greater than five which is counted as one and is added to the next figure making it up to 9.
Therefore, the quantity that expresses the sum of the given parameters is =5797.9 g .
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Can someone help me finish this? (images attached)
Answer: Number 7 is molecules, Number 3 is the nuclear force, Number 8 is chemical
Explanation: For number 3 I don't know what other name is their for the nuclear force.
I hope this helped!
The answer is: To think of different kinds of materials to use
Glass, Metal, Wood, Ceramic, Plastic are different kind of materials to be used.
Glass is versatile material, which is made up of sand and silicon dioxide. Most familiar glass today is soda-lime silica glass. they have properties like hardness, transparency and heat resistance.
Metals are the important materials found in earth and they are used in a vide variety of applications. Aluminium, iron and copper are some of the examples of metals. they can combined together to makes alloys. they have properties like conductivity, lustre and malleability.
Wood is the most common and easily available material. two kinds of wood are there hardwood and softwood. they are used in construction and as fuel for burning.
Ceramic are substances which are inorganic and non-metallic in nature. they are used to make pots, vessels etc. they are hard, heat resistant, and resistant to corrosion
Plastic are up of long chain of molecules. they are used in the production of variety of substances.. there are different types of plastics. they are cost friendly, strong and durable, resistant to water and electricity.
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An object has a mass of 12.5 grams and a volume of 2.7 mL
what is the object's density?
Answer:
[tex]4.6\frac{g}{mL}[/tex]
Explanation:
The formula for finding a object's density is:
D = M/V, which means Density equals Mass divided by Volume.
In this case, our mass is 12.5 grams, our volume is 2.7mL, and our density is the unknown we are solving for.
One important thing to keep in mind when finding density is the type of measurements used. Fortunately in this case, we are dividing grams by ml, which have a 1:1 conversion rate.
To find our answer, we just divide 12.5 by 2.7 to get:
[tex]\frac{12.5g}{2.7mL} = 4.6\frac{g}{mL}[/tex]
The true answer is 4.629, where 629 is repeating. However when we apply significant figures, we see our lowest amount of sig fig is 2 digits(in 2.7), so we round to 2 digits in our answer.
Hope this helps!
What is the purpose of photoreceptors?
a. They focus the light coming into the eye.
b. They contract and relax to control the pupil.
c. They change light to electrical signals.
d. They receive light and turn it into an image.
The purpose of photoreceptors are they 'convert light to electrical signals'
Photoreceptors are the cells in the retina that respond to light and in that special cells in the eye's retina that are responsible for converting light into signals that are sent to the brain and photoreceptors give us our color vision and night vision and there are two types of photoreceptor cells rods and cones. when light hits the retina special cells called photoreceptors turn the light into electrical signals. these electrical signals travel from the retina through the optic nerve to the brain and then the brain turns the signals into the images called photoreceptors and the best example is human eye retina is a good example of photoreceptor protein
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Which of the following has the largest second ionization energy and WHY?
A) Ca
B) Ga
C) Ge
D) K
E) Se
Ca has the largest second ionization energy of 589.8 kJ/mol .
The second ionization energy of an element is usually greater than the first because positive charge more strongly attracts electrons than negative charge.
What is ionization energy?Ionization energy, also known as ionization energy, is the minimal amount of energy needed to liberate the most loosely bound electron from an isolated gaseous atom, positive ion, or molecule in physics and chemistry.
Ionization energy, also known as ionization potential, is the quantity of energy needed to remove an electron from an isolated atom or molecule in physics and chemistry.
Ionization energy can be defined simply as a measurement of how difficult it is to remove an electron from an atom or ion or of an atom's or ion's propensity to give up an electron.
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Testing for pH levels can be useful in a variety of ways. Healthcare professionals may use pH tests on saliva or urine samples to help diagnose disorders. pH tests are also performed in the home on water samples from, for example, swimming pools.
3. pH strips measure the number of
__ in a solution.
Answer choices:
ions
charges
protons
A graduated cylinder has a mass of 80.0 g when empty. When 20.0 mL of water is added, the
graduated cylinder has a mass of 100.0 g. If a stone is added to the graduated cylinder, the water level rises to 45.0 mL and the total mass is now 156.0 g. What is the density of the stone?
Answer:
2.24g/
Explanation:
mass of water is found by getting 5he extra mass the cylinder gained after adding
100g-80g=20g - mass of water
Density of water: 1g/cm³ that means that 20g water has a volume of 20cm³
1cm³=1ml; 20cm³=20ml
volume of stone is the extra height the water gained: 45ml-20ml =
25ml
mass of stone is the extra mass now earned:
156g-100g=56g
Density of stone=mass of stone÷divide by volume of stone
56g÷25ml=
2.24g/ml
Inside Earth, it is very hot and this source of heat called
Answer:
Geothermal energy
Explanation:
Hope that helps !!!