Answer:
17
Explanation:
We are given the equation:
[tex]5(3x)- 7y^2[/tex]
and asked to solve when x=3 and y=2. Therefore, we must plug 3 in for x and 2 in for y.
[tex]5(3(3))-7(2)^2[/tex]
Solve according to PEMDAS: Parentheses, Exponents, Multiplication, Addition and Subtraction.
Solve the exponent first.
⇒ (2)²= 2*2=4
[tex]5(3(3))-7(4)[/tex]
Multiply 3 and 3.
⇒3*3=9
[tex]5(9)-7(4)[/tex]
Multiply 5 and 9.
⇒5*9=45
[tex]45-7(4)[/tex]
Multiply 7 and 4.
⇒ 7*4=28
[tex]45-28[/tex]
Subtract 28 from 45.
[tex]17[/tex]
5(3x)-7y² when evaluated for x=3 and y=2 is 17
Scientific predictions can best be described as: a Problems you expect to identify b Questions you expect to ask c Experiments you expect to run d Evidence you expect to find
Answer:
Explanation:a
Scientific predictions are best described as consistent data that are presented in the form of if and then. It is a solution to the problem that may be identified. Thus, option a is correct.
What is scientific prediction?Scientific prediction is a statement that describes the events of the future that are not always correct or incorrect. In scientific research, the experiment is conducted based on the hypothesis to draw conclusions and results that are expected.
The expected results are said to be scientific predictions when they are represented in the form of "if and then" before the analysis of the experimental method and its result are done. It is an account of the events that may possibly take place under specific conditions.
Therefore, option A. scientific prediction is an expected problem.
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A small rock with the mass of 6 g is dropped into a graduated cylinder with 20 mL of water. The water rises to 23 mL. What is the density of the rock?
Answer: The density of the rock is 2g/mL. Hope this helped! :)
Explanation:
V= 3.0mL D=M/V
M= 6.0g
D=6.0g/3.0mL
D= 2.0g/mL
The nucleus of a helium atom is identical to: A) a gamma particle B) an alpha particle C) a beta particle D) all of the above
Answer: D. All of the above
Answer:
B. Alpha Particles
Explanation:
P: Have a Nice Day!
Question 2
Which statement describes a change of matter that I DIFFERENT from the others?
A
Peroxide breaking down into water and oxygen
B
Bubbles forming when a pot of water is heated
A pair of jeans soaked in water drying after hanging outside
D
A block of ice decreating in size due to a change in temperature
Answer:
A. Peroxide breaking down into water and oxygen
Explanation:
Generally when it comes to changes, there are physical and chemical changes. In physical changes, there are no new substances been formed, however in chemical change new substances are formed.
A. Peroxide breaking down into water and oxygen
This is a chemical change.
B . Bubbles forming when a pot of water is heated
This is a physical change
C. A pair of jeans soaked in water drying after hanging outside
This is a physical change
D . A block of ice decreasing in size due to a change in temperature
This is a physical change.
Only option A is different from the rest,hence this is the answer.
How does scientists benefit society
Answer:
scientists benefit the society because they prove many theories, plus they are always finding new solutions to new things
Explanation:
Answer:
The scientist uses specialized training to help solve problems
faced by society.
Explanation:
A P E X
PLEASE HELP I HAVE THIS TEST TOMORROW AM GIVING MORE POINTS THAN I SHOULD!
An unlit match contains approximately 1,000 J of chemical energy. When it burns, the match releases thermal energy and light energy. After it has burned, the remaining match contains 250 J of chemical energy. If the thermal energy was measured to be 400 J, how much light energy did the match emit?
Answer:
match emit 350 J light energy.
Explanation:
By law of conservation of energy, total energy before and after reaction for an isolated system remains constant.
Total energy for unlit match = 1000 j
When it burns type of energy released
thermal energy = 400 j
light energy --> it value is unknown which we have to find
also remaining match has 250 joule of chemical energy
applying law of conservation of energy
energy before match was unlit = energy after match was lit
1000 j = thermal energy + light energy + chemical energy of remaining match
1000 J = 400 J + light energy + 250 J
light energy = 1000 J - 400J - 250J
light energy = 350 J
Thus, match emit 350 J light energy.
Put the following elements in order according to the number of protons they contain: S; Si, Sc; Na Reorder answers 1.Si Reorder answers 2.S Reorder answers 3.Sc Reorder answers 4.Na
Answer:
he oxygen ion you have with 8 protons attracting 10 electrons is larger, ... As a result, the 3Al3+ ion will be smaller than the Si element, which has ... O<Al3+<Si<Al<O2-<Ag<Rb<Cs ... It is fairly easy to arrange the atoms according to atomic size. ... I would put it between Al and Ag .
Explanation:
what are different type of plastids explain them?
Answer:
Explanation:
There are 3 types of plastids :-
1) Chloroplasts:- The green plastids which contain chlorophyll pigments for photosynthesis.
2) Chromoplasts:-The coloured plastids for pigment synthesis and storage.
3) Leucoplasts:- The colourless plastids for monoterpene synthesis found in non- photosynthetic parts of the plants.
They are of three types:-
a) Amyloplasts- stores starch.
b) Proteinoplasts- stores proteins.
c) Elaioplasts- stores fats and oils.
0.15 m acetic acid/sodium acetate aqueous buffer at ph 4.5 is diluted to a concentration of 0.1 m with the addition of water what is the pH of the resulting buffered solution
Answer:
Explanation:
A mixture of a weak acid and its conjugate base (or a mixture of a weak base and its conjugate acid) is called a buffer solution, or a buffer. Buffer solutions resist a change in pH when small amounts of a strong acid or a strong base are added (Figure 1). A solution of acetic acid and sodium acetate (CH3COOH + CH3COONa) is an example of a buffer that consists of a weak acid and its salt. An example of a buffer that consists of a weak base and its salt is a solution of ammonia and ammonium chloride (NH3(aq) + NH4Cl(aq)).
The pH of the resulting buffer solution is 6.60.
How to calculate pH of acidic buffer solution?pH of acidic buffer solution is calculated by Henderson equation which is,
pH =pK[tex]_a[/tex] +log[salt]/log[acid]
As the buffer is diluted the concentration is reduced to half, that is
[acid]=0.075 M
[salt]=0.02 M pK[tex]_a[/tex]=4.74
substituting these values in Henderson's equation for acid buffers,
pH=4.74+log[0.075]/[0.02]
=6.6071
Thus, the pH of resulting buffer solution is 6.6071.
Acid buffers consist of a solution of weak acid and its salt.A commonly used acid buffer is prepared by mixing acetic acid and sodium acetate.
Henderson equation is used to calculate pH of buffer solution and ratio of salt to acid to prepare acid solution. pK[tex]_a[/tex] for acid buffers is constant.
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Which of the following is considered to be a chemical property of matter?
Answer: Meteorhpayne
Explanation: Correct me if im wrong :(
ASAP!
A solution is made by dissolving 125 g of sodium chloride in 1.5 kg of water. What is the percent by mass?
Answer:
8.3334%
Explanation:
You have two masses. To find the percent of sodium chloride in water by mass, you divide the mass of NaCl by water. First, make both units the same. Easiest is to convert kg into g. 1.5kg = 1500g
125g NaCl/1500g H2O = 0.0833333333 ==> 8.3334%
How many significant figures are in 10.060 L?
Answer:
5
Explanation:
you have two zeros that are sandwiched in between and one following a signifincant figure after the decimal.
List 3 common examples of physical changes
Answer: crushing a can, boiling water, breaking a glass
Explanation:
Should your height be measured in meters or centimeters
Your height should be measured in meters. Centimeters is much too small of a unit to measure the several feet most people are.
Q: A wind-up toy that is not wound up...
(drag the check on one)
does not have energy.
has potential energy.
has kinetic energy
has both kinetic and potential energy
S
A wind-up toy that is not wound up will have Potential Energy Hence, The correct option is Option (B)
What is potential energy ?Potential energy is that the energy control by associate object due to its position relative to alternative objects, stresses among itself, its charge, or alternative factors.
The total energy of a mechanical toy is given as follows ;
Total Mechanical Energy = Kinetic Energy + Potential Energy
During the winding up of the coil, the total energy becomes the kinetic energy
The total energy at the point of winding up of the coil = The kinetic energy supplied to the toy by winding the coil
From the first law of thermodynamics, energy can not be created nor destroyed however may be modified from one type to a different
Due to the coil being prevented from unwinding, the kinetic energy stored as Potential energy of the toy
When the toy is operated it then unwinds the coil bringing about motion and converting back the potential energy to kinetic energy by itself as if it was alive.
Therefore, A wind-up toy that is not wound up will have Potential Energy Hence, The correct option is Option (B)
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How can a new element be made?
Answer:
adding or removing protons
Explanation:
Elements are defined by the number of protons they have. If you add or subtract protons then that changes and makes a new element.
Answer:
by changing the number of protons in the nucleus
A liquid that can absorb and release huge amounts of heat energy without much change in the overall temperature of the water has what
A Has a high density capacity
B Has a high surface tension capacity
C Has a high specific leat capacity
D Has a high non-polar capacity
Answer:
Im pretty sure the answers b
Explanation:
Because if its talking about overall tempature the it means ihas tension with high surface.
If you drop an object with a mass of 3.66 grams and a volume of 4 mL into a beaker containing dish soap, would it float or sink? Dish soap has a density of 0.93 g/mL
A single atom of an element has 11 protons, 11 electrons, and 12 neutrons. Which element is it? a V b Na c Mg d Se
Answer:
B. Na
Explanation:
To identify an atom, you simply need to look at the number of protons. This atom has 11 protons. On the periodic table, you can see that the element with 11 protons is sodium (Na).
While burning coal and charcoal, you notice that coal releases more heat than charcoal. That means that the... 1. elastic energy 2.gravitational energy 3.chemical potential energy is 1.lower 2. higher in charcoal than in coal
Answer:
3). Chemical potential energy
1). lower in charcoal than in coal.
Explanation:
Chemical potential energy is defined as the energy that can be absorbed or stored in a substance's chemical bonds. It can be released when there is a change in the number of particles of the substance.
As per the question, coal releases more heat than charcoal because 'the chemical potential energy of charcoal is lower than the coal' and hence, the latter would release more heat on burning i.e. the energy that was absorbed in the chemical bonds of the substance. Hence, option 3 and 1 are the correct answers.
In carbon dioxide (CO2), how many grams of oxygen (O) would there be if there are 24 grams of carbon (C)?
Answer:
64g of Oxygen
Explanation:
Firstly, carbon and oxygen react to form CO2 as follows;
C + O2 => CO2
According to the equation, one mole of C reacts with one mole of O2 to give one mole of CO2
Since molar mass of C= 12g/mol, O= 16g/mol
One mole of (C) contains 12g
One mole of O2 contains 16(2) = 32g
Hence, If there are 24g of C, there would be 24 × 32 / 12
= 768/12
= 64g
Hence, there would be 64g of oxygen if there are 24g of Carbon
A jeweler has five rings, each weighing g, made of an alloy of silver and gold. She decides to melt down the rings and add enough silver to reduce the gold content to . How much silver should she add
Complete question :
A jeweler has five rings, each weighing 18 g, made of an alloy of 10% silver and 90% gold. She decides to melt down the rings and add enough silver to reduce the gold content to 75%. How much silver should she add?
Answer:
Kindly check explanation
Explanation:
Given the following :
Weight of each alloy = 18g
Initial % of Silver = 10% = 0.1
Initial % of Gold = 90% = 0.9
New % of gold = 75% = 0.75
Hence, new % of silver will be (1 - 0.75) = 0.25
Let the amount of silver to be added = s
Hence,
Initial gold content = final gold content + added silver
18 * 0.9 = 0.75(18 + s)
16.2 = 13.5 + 0.75s
16. 2 = 13.5 + 0.75s
16.2 - 13.5 = 0.75s
2.7 = 0.75s
s = 2.7 / 0.75
s = 3.6
S = 3.6
Hence the amount of silver needed per ring in other to reduce the gold content = 3.6g
Total for the 5 rings = (3.6 * 5) = 18g
An air mass that originates over land in central america is most likely
Answer: An air mass that originates over land in Central America is most likely warm & dry.
she adds 1.5 mL, 0.75 mL, and 1.2 mL. Her measurements of the oil are blank
Answer:
The total measurements of the oil is 3.45mL
Explanation:
Given
1.5 mL, 0.75 mL, and 1.2 mL.
Required
Determine the total
To get the total, we simply add the given volumes together.
[tex]Total = 1.5 mL+ 0.75 mL + 1.2 mL[/tex]
[tex]Total = 3.45mL[/tex]
Hence;
The total measurements of the oil is 3.45mL
why is sodium chloride soluble in water
Answer: because the very polar water molecules attract both the positively charged sodium ions and the negatively charged chloride ions.
need help asp thank you
Answer:
formed at earths surface
Explanation:
so easy
The typical capacity for human lungs is approximately 5800 mL. At a temperature of 37C (average body tempurature) and pressure of 0.98 atm, how many moles of air do we carry inside our lungs?
Answer:
0.22 moles of air we carry inside our lungs.
Explanation:
An ideal gas is a theoretical gas that is considered to be composed of point particles that move randomly and do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.
The gas laws are a set of chemical and physical laws that allow determining the behavior of gases in a closed system. The parameters evaluated in these laws are pressure, volume, temperature and moles.
The ideal gas law is an equation that relates the variables pressure P, temperature T and volume V if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases as follows:
P * V = n * R * T
In this case:
P= 0.98 atmV= 5800 mL= 5.8 L (being 1,000 mL= 1 L)n= ?R= 0.082 [tex]\frac{atm*L}{mol*K}[/tex]T= 37 C= 310 K (being 0 C= 273 K)Replacing:
0.98 atm* 5.8 L= n* 0.082 [tex]\frac{atm*L}{mol*K}[/tex] * 310 K
Solving:
[tex]n=\frac{0.98 atm* 5.8 L}{0.082 \frac{atm*L}{mol*K} *310 K}[/tex]
n= 0.22 moles
0.22 moles of air we carry inside our lungs.
convert 0.00043 dam to hm
Which statements differentiate DNA and RNA? Check all that apply.
Answer:
A:DNA is a double helix, and RNA is a single strand.
C:DNA is involved only in transcription, and RNA is involved in both transcription and translation.
E:DNA does not have uracil as a nitrogen base, but RNA does have uracil as a nitrogen base.
Explanation:
I did the test an Edge.
Which statement accurately compares the trends in atomic number and atomic mass in the periodic table
the Answer is C
Both the atomic mass and the atomic number increase from left to right.
Answer: is C
Explanation:
Both the atomic mass and the atomic number increase from left to right