Answer:
Strontium, as opposed to other elements on the periodic table (with the exception of others in the same group/column i.e., the vertical direction), is a good substitute for Calcium because they are in the same group.
Explanation:
This is because elements of the same group behave similarly and have similar properties. This is due to the fact that elements of the same group (in the vertical direction) have the same number of valence electrons.
Students are experimenting with a substance that they
think can be added to soil to increase the number of
flowers a certain plant will make. They set up 20 pots of
soil, each planted with the same type of seed. They
divide the pots into two groups and add 15 drops of the
substance to pots in one group and only 10 drops to pots
in the other group. After the plants grow for four weeks,
the students count how many flowers each plant has
made
What does this experimental investigation lack?
a control group
an independent variable
a dependent variable
a procedure
Answer:
A: Control Group
Explanation:
The control group is part of an expierment left untouched by anything that could possibly alter it, in the case of this question, the students have two groups of plants that have drops of liquid that could alter them, in order to see the growth, and to see if the liquid actually did anything, in order to do so, you would have to have a untouched plant, that shows what it looks like with out any alteration from researchers. So the answer would be control group.
Answer:
i think control group?
Explanation:
meow x3 UwU
A 36.04 g sample of water is boiled. When the steam expands to fill the vessel how many atoms of hydrogen would be found in the sample?
Answer:
The number of hydrogen atoms in 36.04 g sample of steam is 2.408 × 10²⁴ atoms of hydrogen
Explanation:
The given parameters are;
The mass of the sample of water, H₂O = 36.04 g
From the principle of conservation of matter, the mass of the water = The mass of the steam, therefore;
The mass of the steam = 36.04 g
The molar mass of H₂O = 18.01528 g/mol
Therefore, the number of moles, n, of H₂O in the 36.04 g of steam is given as follows;
n = Mass/(Molar Mass) = (36.04 g)/(18.01528 g/mol) = 2.00052399963 ≈ 2 moles
The number of molecules of H₂O per mole of H₂O is geven by the Avogadro's number = 6.02 × 10²³ molecules
Therefore;
The number of H₂O in 2 moles of H₂O = 2 × 6.02 × 10²³ = 1.204 × 10²⁴ molecules
The number of hydrogen atoms per molecule of H₂O = 2 hydrogen atoms
Therefore;
The number of hydrogen atoms in the 1.204 × 10²⁴ molecules of H₂O = 2 × 1.204 × 10²⁴ molecules of H₂O
Which gives;
The number of hydrogen atoms in the 1.204 × 10²⁴ molecules of H₂O = 2.408 × 10²⁴ atoms of hydrogen
Therefore;
The number of hydrogen atoms in 36.04 g sample of steam = 2.408 × 10²⁴ atoms of hydrogen.
how many significant figures are in the number 0.001022?
Answer:
4 sig figs.
Explanation:
Significant Figures Rules:
1. Anything that isn't a zero is a sig fig
2. If a decimal point comes after the ones digit, everything before the decimal is counted as sig fig (i.e 2000. would be 4 sig figs).
3. If we are dealing with small decimals, the zero before and after the decimal (i.e 0.002) is a placeholder and is not counted as sig figs.
4. Any zeros between 2 significant digits is considered in sig figs (i.e 2002 would be 4 sig figs).
We look at 0.001022.
We know that 0.00 are not sig figs and are placeholders.
We know that 1022 are significant digits and figures, and we have 4 of them.
Therefore, we have 4 sig figs.
My answer to the question is 4 significant figures.
HELP ASAP PLEASE
Use the word Precision in a sentence relating to chemistry!
Answer:
I needed to use good precision in my measurement for my chemistry lab
Explanation:
Circle the molecule(s) in the atmosphere that come from animals. (circle all that apply)
a. Carbon dioxide, CO,
b. Helium, He
c. Methane, CH
d. Oxygen, O2
Answer:
A and C
Explanation:
A; Animals inhale and exhale, breath oxygen, leave carbon dioxide.
C; We fart, so do they! (farts are a release of methane gas from our bodies) Just ask my dog...
Hope this helped!
The molecule(s) in the atmosphere that comes from animals is -
a. Carbon dioxide, CO2c. Methane, CH4Humans and other animals contribute to the atmospheric gas cycle such as nitrogen gas, oxygen gas, carbon dioxide, and other gases. Animals give up mainly two gases in the atmosphere that are:
Carbon dioxide: during cellular respiration, animals release carbon dioxide as a waste product with energy. This carbon dioxide is removed from the body of animals to the atmosphere.Methane is a gas that is also released by the animals to the atmosphere but in very low concentration or quantity. During the digestion process, methane gas is formed in the digestion tract. methane will be released as burp mainly.Thus, the molecule(s) in the atmosphere that comes from animals is -
a. Carbon dioxide, CO2c. Methane, CH4Learn more about:
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Is the number 5 x 10-4 greater or less than 1.0?
Answer:
Greater
Explanation:
Anton van Leeuwenhoek used a microscope to observe
tiny creatures swimming in a drop of pond water.
How did his observations contribute to the cell theory?
A. He showed that living cells come from other living cells.
B. He was the first person to observe and identify living cells.
C. He was the first person to observe dead plant cells.
D. He showed that all plants and animals are made of cells.
Answer:
b
Explanation:
what can you say about the average distance from the nuclease of an electron the 2's orbital as compared with a 3s orbital
Answer:
A 3s orbital is at a greater average distance from the nucleus than a 2s orbital
Explanation:
As the principal quantum number n increases, the distance of the orbital from the nucleus increases. Hence if we consider the 2s and 3s orbitals, it is easy to see that the 3s orbital is at a greater distance from the nucleus than the 2s orbitals.
This is clearly seen when we plot the radial distribution against the distance from the nucleus. This enables us to visualize the region in space in which an electron may be found.
7. How many significant figures are in the following numbers?
a. 0.0120350
b. 10.020
c. 12
d. 3.40 x 103
Suppose that 7.25 x 10^22 atoms of a hypothetical element have a mass of 3.88 g. What would be the molar mass (g/mol) of this element ? Correct number of sig figs are required.
Answer:
32.23 to 4 significant figures.
Explanation:
The molar mass of the element is the mass of 6.022 * 10^23 atoms (Avogadro's number).
So by proportion it is 6.022 * 10^23 * 3.88 / 7.25 * 10^22
= 32.23 to 4 significant figures.
wafting the air above a chemical is one way to it directly
Answer:
Explanation:
All it takes is a momentary lapse in concentration. When you are in the laboratory and take a direct sniff of the chemicals you are using, you run the risk of damaging your mucous membranes or your lungs.
A sample of aluminum weighs 100 grams and has a volume of 37.03 cm. What is the density of
aluminum?
Answer:
2.7005 g/cm²
explanation: as we know density=mass/volume
Which of the folling ion or atom has smallest size?
a. CI
b. CI-
c. K
d. K+
In what state of matter do the particles spread apart and fill all the space availble to them?
a)energy
b)liquid
c)solid
d)gas
how do groups and periods on the periodic table differ??
Answer:
Periods are horizontal rows while the groups are the vertical columns on the periodic table.
Every Methane molecule looks different. True or false?
please use vocabulary that i can understand
Answer:
False
Explanation:
Molecules of the same substance are made up of the same type of atoms and look exactly alike.
Hence, if I have two molecules of methane having exactly the same atoms of carbon and hydrogen,the both are indistinguishable from each other based on appearance.
Hence all molecules of methane are exactly alike if they are composed of atoms of the same isotope of hydrogen and carbon.
What is chemistry? How is it used in your everyday life? Give at least two examples and explain your answers. Must have at least 4 sentences to get full credit.
Which statement best describes chemical properties of matter?
Answer:
Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form.
Explanation:
i took the test:P
Hope this helps!
Dmitri Mendeleev developed a chart-like arrangement of the elements called the ______ . He stated that if the elements were listed in order of increasing ______, their properties repeated in a regular manner. He called this the ______ of the elements. The arrangement used today differs from that of Mendeleev in that the elements are arranged in order of increasing ______. Each horizontal row of elements is called a(n) ______. Each vertical column is called a(n) ______, or , because of the resemblance between elements in the same column, a(n) ______.
Answer:
Explanation:
Dmitri Mendeleev developed a chart-like arrangement of the elements called the Periodic Table ______ . He stated that if the elements were listed in order of increasing atomic mass______, their properties repeated in a regular manner. He called this the periodicity of properties ______ of the elements. The arrangement used today differs from that of Mendeleev in that the elements are arranged in order of increasing atomic number______. Each horizontal row of elements is called a(n)period ______. Each vertical column is called a(n) column_____, or , because of the resemblance between elements in the same column, a(n) __group____.
1. Dmitri Mendeleev developed a chart-like arrangement of the chemical elements called the: periodic table.
2. According to Dmitri Mendeleev, the properties of chemical elements are repeated in a regular manner, if the chemical elements were listed in order of increasing: atomic mass.
3. Dmitri Mendeleev called the increasing order of chemical elements on the periodic table: the Periodic Law of the elements.
4. The arrangement used today differs from that of Dmitri Mendeleev in that the chemical elements are arranged in order of increasing: atomic number.
5. Each horizontal row of chemical elements is called a: period.
6. Each vertical column is of chemical elements is called a: group.
7. Because of the resemblance between chemical elements in the same column, each vertical column is called a: family.
Dmitri Ivanovich Mendeleev was a Russian chemist and inventor who was born on the 8th of February, 1834 in Tobolsk, Russia.
He formulated the Periodic Law and devised the periodic table of chemical elements.
The Periodic Law of chemical elements stated that the properties of all chemical elements are repeated in a regular manner, provided the chemical elements were arranged (listed) in order of increasing atomic mass.However, the modern periodic table of chemical elements differ because the chemical elements are arranged in order of increasing atomic number.On a periodic table, each horizontal row of chemical elements is called a period while each vertical column is of chemical elements is called a group.
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Which part of an atom is mostly empty space?
A) Nucleus
B) Proton cloud
C) Electron cloud
D) Neutron
Answer:
Answer is C. Electron cloud
Explanation:
<3
what is reactivity siries of metal??
Answer:
It's a list of metals from most to least reactive.
Explanation:
You should be able to find it listed really easily online.
An experiment looking at structures smaller than a cell would most likely employ a
Answer Scientist
Explanation:
Question 6
1 pts
A scientist is studying a homogeneous solid with a consistent and ordered arrangement in
the lab. Which specialty is the scientist most likely working in?
Answer:
He is probably studying Geomorphology.
Explanation:
Geology is the science that studies the composition, structure, dynamics, and history of planet Earth, the processes by which it has evolved including everything that has to do with its natural resources and with this the processes that affect the surface, and therefore, the environment.
Geomorphology is a branch of geosciences, more specifically geography and geology. One of his most interesting models explains the ways in which the earth's surface is the result of a consistent dynamic balance.
What is the mass of an object when the volume is 50.0mL and the density is 1.5g/mL
What is the relationship between the sequence of DNA’s subcomponents and the properties of DNA? 1. The amino acid sequence along a segment of DNA determines the three-dimensional shape of the protein that will be produced. 2. The deoxyribose sequence in a DNA molecule determines the complementary molecule that will form double stranded DNA. 3. The nitrogenous base sequence along a segment of DNA determines the amino acid sequence that will be produced. 4. The sequence of enzymes in a DNA molecule determines the direction in which DNA will be transcribed into mRNA.
Answer:
3.
Explanation:
There are four nitrogenous bases in a DNA including guanine (G), adenine (A), cytosine (C) and Thymine (T) and together they form the nitrogenous base sequence arranged in a specific order of three letters such as GAC and TAG to form a genetic code.
These nitrogenous base sequences forming genetic code are amino acid specific and determine the amino acid sequence in DNA. for example: CTT determines leucine and GTT determines valine.
Hence, the correct option is "3".
Water is a pure substance. Which of the following is true about water? (5 points)
a.) Its compounds can only be chemically separated into the elements that make it up.
b.)Its compounds can only be physically separated into the elements that make it up.
c.)It is made up of a variety of compounds, each with a different set of properties.
D.) it is made up of one element and one compound, each with the same properties.
Answer:
a.) Its compounds can only be chemically separated into the elements that make it up.
The compound of water can only be chemically separated into the elements that make it up. The correct option is A.
What is a compound?A compound is made up of atoms from different elements that have been chemically combined in a specific ratio.
A mixture is a combination of two or more substances in which no chemical reaction or combination occurs. Compounds are made up of different elements arranged in a specific order via chemical bonds.
Atoms/molecules are (chemically physically) combined in a compound so that the elements that comprise the compound (retain/lose) their identities and take on a new set of properties.
The most common chemical methods of isolation and purification are distillation, crystallization, adsorption, membrane procedures, absorption and stripping, and oxidation.
Because each water molecule is made up of two hydrogen atoms and one oxygen atom, water can only be decomposed chemically.
Thus, the correct option is A.
For more details regarding a compound, visit:
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4) Which is a characteristic of a solution? * Its particles scatter light. Its particles are evenly distributed. Its particles settle out.
Answer: The correct answer is B. It’s particles are evenly distributed. (:
Explanation:
Answer:
b
Explanation:
An atom has an atomic number of 16 and a mass number of 33.
What is the symbol of the element?
How many protons does the atom contain
How many neutrons does the atom contain?
How many electrons does the atom contain?
Answer:
sulfur
Explanation:
protons: 16 neutrons: 16 electrons: 2,8,6 i hope this helps!
A 1.0 m solution of a compound with 2 ionizable groups (pka's = 6.2 and 9.5; 100 ml total) has a ph of 6.8. what are the concentrations of the relevant acid and conjugate base?
Answer:
[H₂A] = 0.2M
[HA⁻] = 0.8M
Explanation:
A compound with 2 ionizable groups has as equilbriums:
H₂A ⇄ HA⁻ + H⁺ ⇄ A²⁻ + H⁺
A pH of 6.8 is near to the first equilibrium:
H₂A ⇄ HA⁻ + H pKa = 6.2
To determine concentrations of the acid H₂A and conjugate base HA⁻ we use H-H equation:
pH = pKA + log [HA⁻] / [H₂A]
6.8 = 6.2 + log [HA⁻] / [H₂A]
0.6 = log [HA⁻] / [H₂A]
3.981 = [HA⁻] / [H₂A] (1)
As concentration of the buffer is 1.0M:
1M = [HA⁻] + [H₂A] (2)
Replacing (2) in (1):
3.981 = 1- [H₂A] / [H₂A]
3.981[H₂A] = 1 - [H₂A]
4.981 [H₂A] = 1
[H₂A] = 0.2M
And [HA] = 1M - 0.2M = 0.8M
What is the mass of substance that exactly fills a 247.2 mL container? The density of the substance is 0.81 g/mL. Give the answer with two decimals.
Answer:
mass = 200.23 gExplanation:
The density of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]
Since we are finding the mass
mass = Density × volumeFrom the question
Density = 0.81 g/mL
volume = 247.2 mL
Substitute the values into the above formula and solve for the mass
mass = 0.81 × 247.2
= 200.232
We have the final answer as
mass = 200.23 g to 2 decimal placesHope this helps you