Answer: K and Mg
Explanation:
The first one refers to the atomic radius and increases going down and to the left on the periodic table. K is in between Rb and Na.
Fill in the blank... spelling counts.
Speed is the ______ something travels divided by the _____ It takes to travel that dinstance.
Answer:
[tex]speed = \frac{distance}{time}[/tex]
(3.1 x 10^3) (1.00 x 10^7) =
Answer:
(3.1 x 10^3) (1.00 x 10^7) = 31000000000
group of students is investigating whether the force of friction depends on the nature of the surfaces in contact. The students push two pieces of wood each with the same force on a table. One piece of wood is smooth and the other is rough. The distance traveled by each piece of wood is shown.
Experimental Observations
Student 1 Student 2 Student 3 Student 4
Distance traveled by smooth piece of wood 20 cm 18 cm 16 cm 19 cm
Distance traveled by rough piece of wood 15 cm 12 cm 10 cm 11 cm
What was the outcome variable (dependent variable) in this experiment?
Group of answer choices
Distance traveled
Smooth wood
Rough wood
Number of students
Answer:
Distance traveled.
Answer: distance traveled
Explanation: I just got the answer right.
The melting and boiling points of a group of elements decrease as you go down the group, while their reactivity increases.
a.. Are the elements from the first group or the second last group of the Periodic Table?
b ..Does this group consist of metals, metalloids, non-metals or a mix?
c.. Identify two elements in this group.
Answer:
a) first group
b) metals
c) K - potassium, Li - lithium
Explanation:
a) they are the alkali metals
b) they're alkali metals lol
c) just look at a periodic table :P
calculate the molarity of a solution made by dissolving 3.7 moles of sodium chloride in 8.7 liters of water?
Answer:
Molarity = 0.425 M
Explanation:
Given data:
Number of moles = 3.7 mol
Volume of solution = 8.7 L
Molarity of solution = ?
Solution:
Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.
Formula:
Molarity = number of moles of solute / L of solution
Molarity = 3.7 mol/8.7 L
Molarity = 0.425 M
1) The speed constant was determined for the first order decomposition of an organic compound at various temperatures:
Calculate the activation energy for the reaction. Build a graph of Arhenius
2) The hydrolysis of sucrose. in which a sucrose molecule is broken in a glucose molecule and a fructose molecule, is part of the digestive process. Calculate the speed constant for the hydrolysis of sucrose at 35,0 C knowing that k=1,0x10^-3 L mol^-1s^-1 at 37 C and that the activation energy is 108kj mol^-1
Answer:
1) Eₐ = 100.3 kJ/mol
2) k = 7.62×10⁻⁴ M⁻¹s⁻¹
Explanation:
1) Make an Arrhenius graph by plotting ln(k) on the y-axis and 1/T on the x-axis (don't forget to convert temperature to Kelvin).
The slope of the line is equal to -Eₐ/R.
-Eₐ/R = -12065
Eₐ = 100,300 J/mol
Eₐ = 100.3 kJ/mol
2) Since we know the slope of ln(k) vs 1/T is -Eₐ/R, we can say:
-Eₐ/R = (ln(k₂) − ln(k₁)) / (1/T₂ − 1/T₁)
Plug in values and solve for k:
-(108,000 J/mol) / (8.314 J/mol/K) = [ln(k) − ln(1.0×10⁻³)] / [1/(35+273.15 K) − 1/(37+273.15 K)]
-12990 = [ln(k) + 6.91] / (2.09×10⁻⁵ K⁻¹)
-0.272 = ln(k) + 6.91
ln(k) = -7.18
k = 7.62×10⁻⁴ M⁻¹s⁻¹
What are the possible consequences of adding a chemical to the environment
Answer:
The release into the air of chemicals and particles can cause direct damage to the troposphere (air pollution); alter the composition and function of atmospheric layers (greenhouse effect) or other indirect damages (ozone layer depletion).
Explanation:
How many protons and electrons does a hydrogen atom have?
A hydrogen atom contains 1 electron, 1 proton
Explanation:
Right amount of gravity
the answer is: 9.80665
Question 20 of 66
Which of the following species has the same number of protons as Fe3+?
A) Mn3+
B) Co2+
C) Fe2+
D) Nit
E) CO3+
Fe²⁺ has the same number of protons as Fe³⁺.
In order to know the number of protons of a species, we need to look for the atomic number (Z) in the Periodic Table.
The atomic number of Fe is 26, so it has 26 protons. Since protons are in the nucleus, they are not lost nor gained. Fe³⁺ results from Fe losing 3 electrons, but it has 26 protons as well.
Taking this into account, let's consider the number of protons of the following species:
A) Mn³⁺. It has 25 protons like Mn (Z = 25).
B) Co²⁺. It has 27 protons like Co (Z = 27).
C) Fe²⁺. It has 26 protons like Fe (Z = 26).
D) Ni. It has 28 protons (Z = 28).
E) Co³⁺. It has 27 protons like Co (Z = 27).
Fe²⁺ has the same number of protons as Fe³⁺.
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The vaporization of Br2 from the liquid to the gas state requires 7.4 kcal/mol. write a reaction showing heat as a product or reactant
Answer:
Br₂(l) + ΔV → Br₂(g)
Explanation:
When a chemical or phase change occurs during a chemical process some heat is absorbed or released. For the process of vaporization of a substance, the heat (Usually required) is ΔV (How many energy is required for the process occurs).
In the vaporization of Br2 there are required 7.4kcal/mol, Δv. The reaction is:
Br₂(l) + ΔV → Br₂(g)Meaning of biocentric
can i please get brainlyest
"the view or belief that the rights and needs of humans are not more important than those of other living things."
Answer:
the view or belief that the rights and needs of humans are not more important than those of other living things.
explanation:
In Natural selection, individuals whose unique characteristics are well-suited for an environment tend to survive and produce more offspring. true or false? i need this help!right now!
Answer:
True
Explanation:
True. If an animal has attributes to it that help it survive better in an environment, it will survive better than its counterparts who do not have this attribute. More survival = More offspring
Answer:
True.
Explanation:
It's called survival of the fittest. Animals are genetically supposed to be well suited to their environment and if they aren't, they die out.
Read the statement below and decide if it represents physical change or chamical change.
Iron is heated, causing it to melt.
O Physical Change
Chemical Change
please help me :( What is the correct ratio of carbon to hydrogen to oxygen in glucose (C6H120.)?
12:12:6
01:2:1
02:1:1
6:6:12
Answer:
Either 12:12:6 or 6:6:12
Explanation:
If I remember correctly the answer should be 6:6:12
II. Pure magnesium metal is often found as ribbons and can easily burn in the presence of oxygen. When 3.86 g of magnesium ribbon burns with 155ml of oxygen at 1.0 atm and 275 K , a bright, white light and a white, powdery product is formed, magnesium oxide. How many grams of excess reactant remain?
Answer:
[tex]Excess=3.53g[/tex]
Explanation:
Hello,
In this case, the undergoing chemical reaction is:
[tex]2Mg(s)+O_2(g) \rightarrow 2MgO(s)[/tex]
Next, we identify the limiting reactant by computing the moles of magnesium oxide yielded by 3.86 g of magnesium and 155 mL of oxygen at the given conditions via their 2:1:2 mole ratios and the ideal gas equation:
[tex]n_{MnO}^{by \ Mg}=3.86gMg*\frac{1molMg}{24.3gMg}*\frac{2molMgO}{2molMg} =0.159molMgO\\\\n_{MnO}^{by \ O_2}=\frac{1atm*0.155L}{0.082\frac{atm*L}{molO_2*K}*275K} *\frac{2mol MgO}{1molO_2} =0.0137molMgO[/tex]
It means that the limiting reactant is the oxygen as it yields the smallest amount of magnesium oxide. Next, we compute the mass of magnesium consumed the oxygen only:
[tex]m_{Mg}^{consumed}=0.0137molMgO*\frac{2molMg}{2molMgO} *\frac{24.3gMg}{1molMg} =0.334gMg[/tex]
Thus, the mass in excess is:
[tex]Excess=3.86g-0.334g\\\\Excess=3.53g[/tex]
Regards!
Calcium reacts with oxygen to make calcium oxide, CaO. What is the theoretical yield (g) of CaO(s) that could be prepared from 7.75 g of Ca(s) and 2.44 g of O2(g)
Answer:
Explanation:
2Ca + O₂ = 2CaO
80 g 32 g 112 g
given amount of Ca = 7.75 g
it will require oxygen = 32 x 7.75 / 80 = 3.1 g
but available oxygen = 2.44 so oxygen is the limiting reagent .
32g oxygen reacts with calcium to give 112 g of calcium oxide
2.44 gram of oxygen reacts with calcium to give 112 x 2.44 / 32 of CaO .
= 8.54 gram .
Theoretical yield of CaO = 8.54 gram.
Calculate the density of an
object with a mass of 58g and a
volume of 20 mL.
Enter
Answer:
D = 2.9 g/mL
Explanation:
Density = Mass over Volume
D = m/V
Step 1: Define
m = 58 g
V = 20 mL
D = unknown
Step 2: Substitute and Evaluate for Density
D = 58 g/20 mL
D = 2.9 g/mL
How do elements tend to structure the molecules of life?
Answer:
The six most common elements in living things are carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur. Atoms of these elements combine and form thousands of large molecules. These large molecules make up the structures of cells and carry out many processes essential to life.
Explanation:
hope that helped
Different elements combine together to form an organism and other essential organic and inorganic molecules for the life and survival of organisms.
In multicellular organisms, such as animals, atoms form molecules by coming together. These atoms are present in the elements. Molecules can interact to form cells. Cells combine to form tissues, which make up organs.
At the most basic level, all organisms are made of a combination of elements:
carbon is the most common and essential element for the lifeCarbon has the ability to form a wide range of compounds.With other elements most commonly, hydrogen, the oxygen they form various molecules such as carbohydrates, lipids, and many more.With other molecules like phosphate, sulfur, and nitrogen they make essential macromolecules and nutrients like protein, vitamin, and nucleic acid essential for life.Thus, Different elements combine together to form an organism and other essential organic and inorganic molecules for the life and survival of organisms.
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how much valence electrons does aluminum have
Answer:
3
Explanation:
It is in the third column or group on the periodic table
in what and what no energy is used?
Answer:
Energy is used when someone is climbing while energy is not used when someone is going down the slope
1. As an electron in an atom moves from a higher energy state to a lower energy state, the atom
(A) becomes a negative ion
(C) releases energy
(B) becomes a positive ion
(D) absorbs energy
Answer:
(C) releases energy
Explanation:
From Bohr's model of the atom, we can understand the energy transitions involved when an electron moves from one energy level to another.
An electron in an energy level has a definite amount of energy associated with it at that level. When electrons change state, they must absorb or emit the exact amount of energy which will bring them from initial to final states. When the electron is excited, it moves from the ground state to an excited state, it must must absorb energy. On returning from an excited state, energy is emitted.(C) releases energy
From Bohr's model of the atom:
We can understand the energy transitions involved when an electron moves from one energy level to another.
An electron in an energy level has a definite amount of energy associated with it at that level. When electrons change state, they must absorb or emit the exact amount of energy which will bring them from initial to final states. When the electron is excited, it moves from the ground state to an excited state, it must must absorb energy. On returning from an excited state, energy is released or emitted.Therefore, option C is correct.
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in addition to Earthquake, hurricane, which of the following could be categorized as a "disaster" risk?
Answer:
I think its a World War.
Explanation:
This is just what my sister told me, since the cost for the war could make a country poor and the damage it could cause could lead a country to disaster.
i think d answer is tsunami
100 POINTS!!!!
The passage states that water exists in three states on Earth. Trace the changes in state of matter, from snow-capped mountain, through the water cycle, and finally back to the snow-capped mountain.
A) melting snow; lliquid runoff; liquid water evaporates; water freezes; precipitation of frozen water (snow) back to Earth
B) solid snow melts; liquid water flows to oceans; water evaporates; water condenses to form clouds; snow falls back to Earth
C) solid snow melts; liquid water evaporates; gaseous water vapor condenses; water freezes; precipitation of frozen water (snow) back to Earth
D) solid snow melts; liquid water soaks into ground; plants take up water; water evaporates; water freezes; precipitation of frozen water (snow) back to Earth
YOU CAN HAVE ALL MY POINTS AND THE BRAINLIEST PLS HELP ME!!!!
Answer:
C
Explanation:
solid snow melts; liquid water evaporates; gaseous water vapor condenses; water freezes; precipitation of frozen water (snow) back to Earth
only cycle that makes sense
Answer:
The answer is C
Explanation:
What is convection?
Transfer of heat through objects touching source
Transfer of heat through direct physical contact
Transfer of heat through electromagnetic waves
Transfer of heat through the movement of particles
Answer:
D.
Explanation:
Watts are a measurement of power
Answer:
Watts are a measurement of power, describing the rate at which electricity is being used at a specific moment. For example, a 15-watt LED light bulb draws 15 watts of electricity at any moment when turned on. Watt-hours are a measurement of energy, describing the total amount of electricity used over time.
Please mark as brainliest.
Answer: True
Watts are a measurement of power, used in light bulbs and other electricity. It is also measured as candela (C) in SI Units. The answer to the question is true because of this measurement.
Hope this helps!
2.
_______ properties depend on the amount of
matter present
Answer:
extensive properties
Explanation:
,such as mass and volume, depend on the amount of matter being measured. Intensive properties, such as density and color, do not depend on the amount of the substance present. Physical properties can be measured without changing a substance's chemical identity.
Question 1 of 10 What is molarity a measurement of? O A. The volume of liquid containing a dissolved substance B. The grams of a substance dissolved in a liquid O c. The concentration of a substance dissolved in a liquid O D. The number of moles of a dissolved substance
To do this measure called molarity is commonly used. Molarity (M) is defined as the number of moles of solute (n) divided by the volume (V) of the solution in liters. It is important to note that the molarity is defined as moles of solute per liter of solution, not moles of solute per liter of solvent.
so the answer is D.
hope this helps have a great day....!
According to the concept of molar concentration, molarity is defined as the number of moles of a dissolved substance.
What is molar concentration?Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.
The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.
In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.
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How do I find the hydrated formula?
Answer:
In order to determine the formula of the hydrate, [Anhydrous Solid⋅xH2O], the number of moles of water per mole of anhydrous solid (x) will be calculated by dividing the number of moles of water by the number of moles of the anhydrous solid (Equation
Explanation:
Scientific knowledge is open to change as new information is discovered. Which of the following would NOT be a result of new scientific knowledge?
A
Scientists discover that a type of fungus on this log does not require oxygen for absorption and change the classification system.
B
Scientists publish an article that mentions the historic decline in the population of blue stain fungi.
C
Scientists classify a recently discovered bacterium living on this log using generally accepted naming procedures.
D
Scientists discover a bacterium living on this log that is multicellular and revise their classification