Answer:
A hypothesis is a testable statement that is proposed to explain an observation/theory. In this case, one hypothesis that could be used is: Taller people have longer arms than smaller people. You could also say: As the height of an individual increases, the length of their arms also increases.
Independent variables are the variable that is manipulated. In this case, the independent variable is the height of the individual.
Dependent variables are those that change in response to the independent variable. In this case, the dependent variable is arm length.
how many moles are in 150 grams lf NaOH
Answer:
3.75 mole
Explanation:
molecular mass of NaOH = 39.97 gm
i.e,
==>39.97 gm NaOH contains 1 mole of NaOH
==>1 gm of NaOH contains 1/39.97 mole of NaOH
==>150 gm of NaOH contains (1/39.97) *150 mole of NaOH
==>150 gm of NaOH contains 3.75 mole of NaOH.
A solid, whose original weight was 8.492 grams, was dissolved in water. The
water solution was evaporated down to a small volume, then allowed to sit in a lab
drawer for a week. The resulting weight of the recovered solid was 9.045 grams.
a) Calculate the perfect recovery of the solid ._____
b) Give at least one reason why the percent recovery was greater than 100.0%
Answer:
See below
Explanation:
9.045/8.492 * 100% = 106.5%
There was other solids already dissolved in the water, or dust or other contaminants got into the water. ....or the measurement was incorrect. (like maybe the solid was still wet?)
Answer:
dfgdsgdffgfddffg
Explanation:
dfggffgdgdf
how many atoms are there in 56 moles of silver
Answer:
3.4 x 10²⁵ atoms Ag
Explanation:
To find the amount of silver (Ag) atoms, you need to use Avogadro's number to convert between moles and atoms. Make sure to arrange the ratio in a way that allows for the cancellation of moles. The final answer should have 2 sig figs to correlate with the number of sig figs in the given value (56 = 2 sig figs).
Avogadro's number:
6.022 x 10²³ atoms = 1 mole
56 moles Ag 6.022 x 10²³ atoms
-------------------- x ---------------------------------- = 3.4 x 10²⁵ atoms Ag
1 mole
Two substances both exhibit hydrogen bonding Substance A has a boiling point of 78.4°C. Substance B has a boiling point of
100°C. Which statement correctly compares the substances? (1 point)
O Substance A has stronger bonds, and it takes less energy to undergo a phase change.
O Substance B has stronger bonds, and it takes less energy to undergo a phase change.
O Substance B has stronger bonds, and it takes more energy to undergo a phase change.
O Substance A has stronger bonds, and it takes more energy to undergo a phase change.
Answer: Substance B has stronger bonds, and it takes more energy to undergo a phase change.
Explanation:
Substances with higher boilings have stronger intermolecular forces, and thus require more energy for phase changes to occur.
How can we keep food fresh and cold without electricity?
Pulses A, B, C, and D all travel at 10 m/s on the same string but in opposite directions. The string is depicted at time t=0 in (Figure 1). The small pulses have an amplitude of 2.0 cm, and the large pulse has an amplitude of 4.0 cm.
A) Find the displacement of point P at time t=0.10s .
B) Find the displacement of point P at time t=0.20s .
(a) The displacement of point P at time t=0.10s is determined as +2cm.
(b) The displacement of point P at time t=0.20s is determined as -2cm.
What is displacement?Displacement is the change in position of an object. It is obtained from the product of velocity and time of motion.
x = vt
Displacement of the waves after 0.1 sx = 10 m/s x 0.1 s = 1 m
Each wave will travel 1 m to the right or to the left, depending on the initial direction.
wave B from left will stop at point 0 mwave A from left will stop at point -1 mwave C from right will stop at point 0 mwave D from right will stop at point + 1 mwave B and C superimposed and the displacement will be between A and D.
Amplitude of A = - 2cm
Amplitude of D = + 4cm
Displacement of point P = 4 cm - 2 cm = 2cm
Displacement of the waves after 0.2 sx = 10 m/s x 0.1 s = 2 m
Each wave will travel 2 m to the right or to the left, depending on the initial direction.
wave B from left will stop at point 1 mwave A from left will stop at point 0 mwave C from right will stop at point -1 mwave D from right will stop at point 0 mDisplacement of point P = (amplitude B + amplitude C) + (amplitude A + amplitude D)
Displacement of point P= (2cm - 2cm) + (2 cm - 4cm)= -2cm
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A helium balloon possesses a volume of 2500 L at a temperature of 114 °C. What volume will the balloon have if the temperature changes to 56 °C? The pressure remains constant
Given that the pressure remains constant, if the temperature of the helium balloon decreases to the given value, the volume increases to 2125.5L.
What is Charles's law?Charles's law states that "the volume occupied by a definite quantity of gas is directly proportional to its absolute temperature.
It is expressed as;
V₁/T₁ = V₂/T₂
Given the data in the question;
Initial temperature of gas T₁ = 114°C = (114+273.15)K = 387.15KInitial volume of gas V₁ = 2500LFinal temperature T₂ = 56°C = (56+273.15)K = 329.15KFinal volume V₂ = ?V₁/T₁ = V₂/T₂
V₂ = V₁T₂ / T₁
V₂ = ( 2500L × 329.15K ) / 387.15K
V₂ = 882875LK / 387.15K
V₂ = 2125.5L
Given that the pressure remains constant, if the temperature of the helium balloon decreases to the given value, the volume increases to 2125.5L.
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PLEASE HELP!!!
Choose from the given list of aqueous solutions (A-D).
Solution A has [H3O+] = 3.5×10-5 M.
Solution B has [H3O+] = 3.5×10-4 M
Solution C has [OH-] = 1.3×10-10 M
Solution D has [OH-] = 6.2×10-11 M
Which solution is the least acidic?
Which solution has the highest pH?
Which solution is the most basic?
Which solution is the least basic?
Find pH of all
#A
pH=-log[H+]
pH=-log[3.5×10^{-5}]pH=-log3.5+5pH=4.4#B
pH=-log3.5+4pH=3.4#C
pOH=-log[OH]
pOH=-log[1.3×10^{-10}]pOH=-log1.3+109.8pH=
14-9.84.2#4
pOH=-log6.2+11pOH=10.2pH
14-10.23.8So our answers
solution A is least acidicsolution A has the highest pHsolution A is most basicsolution B is least basicWhat is the volume of a 12.96 g sample of pure hydrogen gas?
The volume of the 12.96 g sample of pure hydrogen gas is 145.24 L
How to determine the mole of hydrogen gas
We'll begin by calculating the number of mole in 12.96 g hydrogen gas. This can be obtained as follow:
Mass of Hydrogen gas = 12.96 gMolar mass of hydrogen gas = 2 g/mol Mole of Hydrogen gas =?Mole = mass / molar mass
Mole of Hydrogen gas = 12.96 / 2
Mole of Hydrogen gas = 6.48 mole
How to determine volume of hydrogen gasTo determine the volume of the pure hydrogen gas, we shall assume that the gas is at standard temperature and pressure (STP). Thus, we shall apply the ideal gas equation as illustrated below:
Temperature (T) = STP = 273 KPressure (P) = STP = 1 atm Gas constant (R) = 0.0821 atm.L/Kmol Number of mole (n) = 6.48 moleVolume (V) =?V = nRT / P
V = (6.48 × 0.0821 × 273) / 1
V = 145.24 L
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An acid is used to bring the pH of a solution from pH 9 to pH 6. How many times more acidic is the final solution than the initial solution?
Select one:
a.
3
b.
10
c.
100
d.
1000
considering the temperature vs. time graph below, how does the temperature at the beginning of a change of state
ompare with the temperature at the end of the change?
O The temperature is always lower.
O The temperature is always the same.
O The temperature is usually lower.
The temperature is usually higher.
Answer:
temp is same
Explanation:
The change of state portionsof the graph are at 2 and 4....and the temp is the same at the beginning and ends.
change of state is a constant temp process
what effect does a catalyst have on a reaccion rate an the products formed in a reaccion
Select the correct answer.
Which of the following is a physical model of the Sun?
O A.
an equation that describes the Sun's motion
OB.
a chart that lists the temperatures of different parts of the Sun
O C.
a computer program that shows how the Sun changes over time
O D. a paragraph that describes the Sun's structure
OE.
a small yellow ball that represents the Sun
In an experiment, the molar mass of the compound was determined to be 118.084 g/mol. What is the molecular formula of the compound?
Answer:
Succinic acid
Explanation:
The most common possibility is succinic acid
As it has decimals after whole no till hundredth it contains OH and C in most of the cases .
Let's check for succinic acid
C4H_6O_64(12)+4(16)+664+48+6118uYes approximately equal
Molecular formula is.
(CH_2)_2(CO_2H)_2
A gas cylinder contains 5.0 kg of propane. How many propane molecules are in the cylinder? The Avogadro constant, L = 6.022 x 1023 mol^-1
A 6.8 × 10^22
B 7.2 x 10^22
C 6.8 × 10^25
D 7.2 x 10^25
[1 mark]
Answer:
Here's your answer.
M(C3H8) = 44 g/mol
n(C3H8) = 5000 (g)/44 (g/mol) = 113,6 mol
[tex] N = n \times N_{a} = 113,6 \times 6,02 \times {10}^{23} \\ \\ = 684,1 \times 10 ^{23} \sf{molecules} [/tex]
Hope it helps you from my side100.0 degrees C a sample of 750mL gas is found. If the temperature of the gas is increased by 300 degrees, what will be the new volume gas
100.0 degrees Celsius = 100.0 + 273 = 373.0 K
[tex]\frac{750}{373.0}=\frac{V_{2}}{673.0} \\ \\ V_{2}=\frac{(673.0)(750)}{373.0} \approx \boxed{1350 \text{ mL}}[/tex]
2) A solution of copper(II) chloride is added to a solution of sodium sulfide
A. Balanced equation:
B. Explanation using activity series and solubility rules as necessary:
The equation is CuCl2 + Na2S ------> 2NaCl + CuS because Na is ahead of Cu in the electrochemical series.
What is a balanced reaction equation?A balanced reaction equation is one in which the number of atoms of each element on the reactant side is equal to the number of atoms of the same element on the product side.
In this case, the balanced reaction equation is;
CuCl2 + Na2S ------> 2NaCl + CuS. The reaction occur thus because Na is ahead of Cu in the electrochemical series and must always displace it from its aqueous solution.
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What is the molality of 35 g acetone dissolved in 0.95 kg water? The molar mass of acetone is 58.1 g/mol.
The molality of 35 g acetone dissolved in 0.95 kg water is 0. 63 mol/kg
How to determine the molalityUsing the formula:
Molality = number of moles of solute÷ mass of solvent
Note that number of moles = mass divided by the molar mass
mass of acetone = 35g
Molar mass of acetone = 58. 1g/mol
Number of moles of acetone = 35÷ 58.1 = 0.602 mole
Molality of acetone = 0. 602÷ 0. 95 = 0. 63 mol/kg
Hence, the molality of acetone is 0. 63 mol/kg
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chemistry can someone solve this?
eimetchuinsumuleavtubronAnswer:
Explanation:
Explain how the period and group trends in atomic radii are related to electron configuration
A neutral atom of Sodium (Na) has an atomic number of 11 and an atomic mass of 23. Therefore, Na has _________________________ protons.
Answer:
11
Explanation:
Atomic number is the number of PROTONS an element has .
Part E
Tsunami evacuation plans often consider the elevation of the community and its distance from the shoreline when
deciding which towns to evacuate. How could this data help in building new homes and communities along coastal areas
that are prone to tsunamis?
Answer:
make the house elevated
what is the definition of oxidation
Answer:
oxidation is an energy that produces reaction in a living cell.
Answer:
the process or result of oxidizing or being oxidized.
Explanation:
Two contribution of chemistry in clothing
Textiles for clothes are also sometimes finished with chemicals, for example, to stiffen them and make them wrinkle-free. Chemicals in their nanoforms are helping make textiles more resistant to water, stains, wrinkles, bacteria and mould. Some of the chemicals can be harmful.
☆...hope this helps...☆
_♡_mashi_♡_
1. Write an unbalanced equation to represent each of the following equations. (Make sure to
show diatomic elements.)
(a) iron and sulfur react to form iron(II) sulfide
(b) hydrogen gas and oxygen gas react to form water
(c) aluminum oxide reacts to form aluminum and oxygen gas
(d) zinc and copper(II) sulfate react to form zinc(II) sulfate and copper
(e) potassium hydroxide and hydrogen bromide react to form potassium bromide and
water
The equation for each reaction is written according to the relevant as below.
Equations of chemical reactionsThe reaction between iron and sulfur to form iron (II) sulfide is written as:
[tex]Fe + S --- > FeS[/tex]
The reaction between hydrogen gas and oxygen gas to form water is written as:
[tex]H_2 (g) + O_2 (g) --- > H_2O (l)[/tex]
The reaction of aluminum oxide to form aluminum and oxygen gas is written as:
[tex]Al_2O_3 --- > Al + O_2[/tex]
Zinc and copper(II) sulfate react to form zinc(II) sulfate and copper as follows:
[tex]Zn+CuSO_4--- > ZnSO_4+Cu[/tex]
Potassium hydroxide and hydrogen bromide react to form potassium bromide and water as follows:
[tex]KOH + HBr --- > H_2O + KBr[/tex]
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A certain atom has 22 protons and 19 electrons. This atom loses an electron. The net charge on the atom is now 4+. If this same atom with 22 protons and 19 electrons were to gain 3 electrons, the net charge on the atom would be
Answer: 0
Explanation:
If 3 electrons were to be gained, then the number of protons would equal the number of electrons.
What most likely happens when water vapor cools?
It changes into gas.
It changes into liquid.
Its temperature increases.
Its temperature remains constant.
Answer:
hello :)
Explanation:
Water vapor in the air reaches its dew point as it cools in the air around the can, forming liquid drops of water. Condensation is the process where water vapor becomes liquid.
Which of the following best describes physical science?
O A.
the study of motion
the study of matter and energy
the study of Earth's structure and processes
the study of reactions
the study of living things
OB.
O C.
OD.
OE.
The study of matter and energy best describes physical science. Hence, option B is correct.
What is physical science?Physical science is the study of the inorganic world.
Physics is a branch of science that studies matter and its motion through space and time, along with related concepts such as energy and force. Physics is one of the "fundamental sciences" because of the other natural sciences (like biology, geology etc.)
Thus the study of matter and energy best describes physical science. Hence, option B is correct.
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okay so if i fail the first time do i repeat the class? or can my teacher still pass me even if i pass the class but fail the test?
Answer:
It depends on what type of test your speaking of, is it a state exam?
If you are passing a class and fail a test you will still pass. If you fail a class you do not need to take it again if you don't want to but you would have to take another class instead.
Why do you think there are many wind systems between a pole and the equator instead of just one large single wind system
As a result, the Poles have high pressure (cold air) while the Equator has low pressure (warm air). Hot air from the Equator rises and goes toward the Poles, while colder air from the Poles lowers and moves toward the Equator, resulting in a continuous wind pattern.