Answer:
Sientific invesigations are different from other investigations because scientific investigations are not and can not be controlled at all.
Explanation:
Scientific investigations are investigations in science that can not have a independent variable and dependent variable in them. these types of investigation is where you observe something and write down the observations.
A mixture contains NaHCO3 together with unreactive components. A 1.75 g sample of the mixture reacts with HA to produce 0.561 g of CO2. What is the percent by mass of NaHCO3 in the original mixture?
Answer:
[tex]\%NaHCO_3=61.2\%[/tex]
Explanation:
Hello.
In this case, since the undergoing chemical reaction is only between the sodium bicarbonate and the acid HA:
[tex]NaHCO_3+HA\rightarrow NaA+H_2O+CO_2[/tex]
For 0.561 g of yielded carbon dioxide (molar mass 44 g/mol), the following mass of sodium bicarbonate (molar mass 84 g/mol) that reacted was:
[tex]m_{NaHCO_3}=0.561gCO_2*\frac{1molCO_2}{44gCO_2} *\frac{1molNaHCO_3}{1molCO_2} *\frac{84gNaHCO_3}{1molNaHCO_3} \\\\m_{NaHCO_3}=1.071g[/tex]
Considering the 1:1 mole ratio between CO2 and NaHCO3. Finally, the percent by mass of NaHCO3 is computed by dividing the mass of reacted NaHCO3 and t the mixture:
[tex]\%NaHCO_3=\frac{1.071g}{1.75g}*100\%\\ \\\%NaHCO_3=61.2\%[/tex]
Best regards.
A 1.75 g sample of the mixture of NaHCO₃ together with unreactive components, that reacts with HA to produce 0.561 g of CO₂, has 61.1% by mass of NaHCO₃.
Let's consider the reaction between NaHCO₃ and HA (generic acid).
NaHCO₃ + HA → NaA + H₂O + CO₂
We can calculate the mass of NaHCO₃ that produced 0.561 g of CO₂ using the following conversion factors:
The molar mass of CO₂ is 44.01 g/mol.The molar ratio of NaHCO₃ to CO₂ is 1:1.The molar mass of NaHCO₃ is 84.01 g/mol.[tex]0.561gCO_2 \times \frac{1molCO_2}{44.01gCO_2} \times \frac{1molNaHCO_3}{1molCO_2} \times \frac{84.01gNaHCO_3}{1molNaHCO_3} = 1.07 g NaHCO_3[/tex]
There are 1.07 g of NaHCO₃ in 1.75 g of the mixture. The percent by mass of NaHCO₃ in the mixture is:
[tex]\%NaHCO_3 = \frac{1.07g}{1.75g} \times 100\% = 61.1\%[/tex]
A 1.75 g sample of the mixture of NaHCO₃ together with unreactive components, that reacts with HA to produce 0.561 g of CO₂, has 61.1% by mass of NaHCO₃.
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1. Calculate the number of moles of oxygen atoms present in 1.50 mol of barium sulfate.
Answer:
[tex]n_O=6.00molO[/tex]
Explanation:
Hello.
In this case, since the molecular formula of barium sulfate is:
[tex]BaSO_4[/tex]
Which has four oxygen atoms, we can also say that one mole of barium sulfate has four moles of oxygen; in such a way, the moles of oxygen atoms in 1.50 moles of barium sulfate are:
[tex]n_O=1.50molBaSO_4*\frac{4molO}{1molBaSO_4} \\\\n_O=6.00molO[/tex]
Best regards.
Which statement best explains why heating a liquid affects its viscosity?
The molecules move faster at higher temperatures and overcome attractions more easily.
The molecules move faster at higher temperatures, and the attractions between them increase.
The molecules move slower at higher temperatures and overcome attractions more easily.
The molecules move slower at higher temperatures, and the attractions between them decrease.
Answer: The molecules move faster at higher temperatures and overcome attractions move easily.
Explanation: edgen. 2020
Answer:
It's A !
The molecules move faster at higher temperatures and overcome attractions more easily.
A hydrated sample weighing 20.0 g is heated in a crucible at 250°C. After cooling the sample now has a weight of 16.5 g.
What is the weight of the water lost from the sample? ______________
If the % water in the sample = g waterg of original sample x 100, what is the % water in the sample?
Given parameters:
Weight of hydrated sample = 20g
Temperature = 250°C
Weight after cooling = 16.5g
Unknown:
Weight of water lost from the sample = ?
Solution:
The weight of water lost from the sample;
Weight of water lost = Weight of hydrated sample - Weight of dry sample
Weight of water lost = 20g - 16.5g = 3.5g
% of water in the sample = [tex]\frac{mass of water}{mass of original sample} x 100[/tex]
Input parameters solve;
= [tex]\frac{3.5}{20} x 100[/tex]
=17.5%
how many hydrogen atoms would be present in 12 molecules of water (h2o)?
3
2
24
12
Answer:
Two water molecules contain 4 hydrogen atoms and 2 oxygen atoms. A mole of water molecules contains 2 moles of hydrogen atoms and 1 mole of oxygen atoms.
Explanation:
A town is looking at multiple solutions for its beach erosion problem. Which factors of beach nourishment should the town consider when making a decision? Select the two correct answers.(1 point)
how they will pay for the cost of the project
how long beaches will be closed during the project
how many people drive near the beaches
how long it will take the new sand to dry
how cold the water temperature is at the time of pumping
Answer:
d
Explanation:
The factors of beach nourishment should the town consider to tackle erosion problem include:
how long it will take the new sand to dry.how cold the water temperature is at the time of pumping.What is erosion?It should be noted that erosion simply means the washing away of the top soil by erosional agents.
In this case, the town should take into consideration how long it will take the new sand to dry and how cold the water temperature is at the time of pumping. This is important to replenish lost nutrients.
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A pumpkin has a volume of 10 cm3 and a mass of 8g. What is the density of the pumpkin
Answer:
Volume (v) = 10 cm^3
Mass (m) = 8g = 8/1000 kg = 0.008 (SI unit of mass is kg)
Density (D) = ?
Now,
D = m/v = 0.008/10 = 0.0008
If you start using 10.0 grams of NaHCO3 and excess of acetic acid, how many moles of CO2 can be formed? How many grams of CO2 can be formed?
Answer:
[tex]n_{CO_2}=0.119molCO_2[/tex]
[tex]m_{CO_2}=5.24gCO_2[/tex]
Explanation:
Hello.
In this case, since the chemical reaction:
[tex]NaHCO_3+CH_3COOH\rightarrow CH_3COONa+H_2O+CO_2[/tex]
And 10.0 grams of sodium bicarbonate (molar mass = 84 g/mol) are reacting in a 1:1 mole ratio with the yielded carbon dioxide, those moles and grams turn out:
[tex]n_{CO_2}=10.0gNaHCO_3*\frac{1molNaHCO_3}{84gNaHCO_3} *\frac{1molCO_2}{1molNaHCO_3} =0.119molCO_2[/tex]
And the mass by considering the molar mass of carbon dioxide to be 44 g/mol:
[tex]m_{CO_2}=0.119molCO_2*\frac{44gCO_2}{1molCO_2} \\\\m_{CO_2}=5.24gCO_2[/tex]
Best regards.
If you start using 10.0 grams of sodium bicarbonate and excess of acetic acid, you can obtain 0.119 moles of CO₂ (5.24 g).
Let's consider the following neutralization reaction.
NaHCO₃ + CH₃COOH ⇒ CH₃COONa + H₂O + CO₂
First, we will convert 10.0 g of NaHCO₃ to moles using its molar mass (84.01 g/mol).
[tex]10.0 g \times \frac{1mol}{84.01g} = 0.119mol[/tex]
The molar ratio of NaHCO₃ to CO₂ is 1:1. The moles of CO₂ formed from 0.119 moles of NaHCO₃ are:
[tex]0.119 mol NaHCO_3 \times \frac{1molCO_2}{1molNaHCO_3} = 0.119 moles CO_2[/tex]
Finally, we will convert 0.119 moles of CO₂ to grams using its molar mass (44.01 g/mol).
[tex]0.119 mol \times \frac{44.01g}{mol} = 5.24 g[/tex]
If you start using 10.0 grams of sodium bicarbonate and excess of acetic acid, you can obtain 0.119 moles of CO₂ (5.24 g).
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which property of physical changes explains why matter is conserved in a physical change
Answer:
b
Explanation:
draw an energy diagram for an endothermic and exothermic reaction and label the diagram
The energy diagram for an endothermic reaction and exothermic reaction are attached in attachments below.
What are endothermic and exothermic reactions?An exothermic reaction is defined as a chemical reaction which involves release of energy in the form of light,heat .In these reactions, energy is transferred from system to surroundings rather than taking energy from surroundings into system as in endothermic reactions.
In an exothermic reaction,change in enthalpy is negative.Therefore, it can be inferred that net amount of energy which is required to start the exothermic reaction is less than the net amount which is released by the reaction.
An endothermic reaction is defined as a chemical reaction which is a thermodynamic process accompanied by an increase in enthalpy of the system.In this process, a system absorbs energy from the surroundings which is mainly thermal energy.
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Ratio of hydrogen chloride
Answer:
Each molecule of HCl is composed of a one-to-one ratio of hydrogen and chlorine.
Explanation:
Gravity would cause the rain falling in which two locations to drain into the area B
Answer:
4 and 3
because i guessed
Gravity would cause the rain falling in (3) and (4) locations to drain into area B. thus these locations are most near to basin area B.
How does gravity affect rainfall?Through watersheds, gravity forces water to flow down on the land and precipitation to fall from clouds. The constant circulation of water between these reservoirs is powered by gravity and solar energy. The water turns from a liquid to a gas as it becomes hotter.
Rainfall can be significantly influenced by mountains. Air must rise to overcome this obstruction once it reaches the mountains. A mountain's windward side causes the air to cool and lose volume as it ascends. As a result, humidity rises, and precipitation and orographic clouds may form.
The image is attached below.
Therefore, these locations are most near basin area B.
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The given question is incomplete, so the most probable complete question is attached in the image.
Which major scientist major contribution was to develop the theory of evolution? (100 points)
Answer:
Alfred Russel Wallace
Why do scientists look for patterns in the world?
A. Patterns never change, no matter what.
B. Patterns can help explain observations.
O C. Patterns are easy for scientists to detect.
D. Patterns are all the same, through all time.
Answer:
B. Patterns can help explain observations.
Explanation:
Hope this helps
Answer:
B. Patterns can help explain observations.
Explanation:
a p e x 2021 :) Have a nice day everyone!
Which describes a characteristic of quartzite? Don't check all that apply.
igneous
foliated
does not split into layers
grains arranged in parallel layers
Answer:
the answer is " does not split into layers"
Explanation:
Quartzite is a non-foliated metamorphic rock and non-foliated rocks have their mineral grains arranged randomly.
What substances make up an iron pot
Answer:
Iron
Explanation:
It is much more difficult to diagnose a
disorder than a
one.
Answer:
disorder examples: eating disorders
Explanation:
dont understand this question fully but hope this helps
TCDD, also called dioxin (C12H4Cl4O2, molar mass 322.0 g/mol), is a potent poison. The average lethal dose in humans is estimated to be 3.0 × 10−2 mg per kg of body weight. (a) How many grams constitute a lethal dose for a 84−kg individual?(b) How many molecules of TCDD does this correspond to?
Answer:
The correct solution is "3.535 × 1018 molecules".
Explanation:
The given values are:
Molar mass
= 322.0 g/mol
Dioxin constitute to 63 kg individual will be:
= [tex]0.03 \ mg\times 63[/tex]
= [tex]1.89 \ mg[/tex]
⇒ [tex]mole=\frac{mass}{molar \ mass}[/tex]
[tex]=\frac{ 1.89\times 10^{-3}}{322}[/tex]
[tex]=5.87\times 10^{-6} \ mol[/tex]
So,
The number of molecules will be:
= [tex]mole\times Na[/tex]
= [tex]5.87\times 10^{-6}\times 6.022\times 1023[/tex]
= [tex]3.535\times 1018[/tex] (molecules)
what piece of equipment changes the signal from the television camera into an electric signal?
Answer:
The transponder
Explanation:
Answer:
Transducer
Explanation:
Transponder was incorrect and made me lose points on the test.
If Brian and his scooter had a mass of 50 kg, how much force would it take for him to accelerate at 0.8 m/s2
Answer:
The answer is 40 NExplanation:
The force acting on an object given it's mass and acceleration can be found by using the formula
force = mass × accelerationFrom the question
mass = 50 kg
acceleration = 0.8 m/s²
We have
Force = 50 × 0.8
We have the final answer as
40 NHope this helps you
What was the oxygen crisis
what is chemical equilibrium and Le chatelier's principle
Le Chatelier's principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change to reestablish an equilibrium. If a chemical reaction is at equilibrium and experiences a change in pressure, temperature, or concentration of products or reactants, the equilibrium shifts in the opposite direction to offset the change.
In Chemical reaction, the concentration of reactant and products shows no net change over the time is called as chemical equilibrium.
How are the chemical properties of a substance related to the chemical changes that the substance
undergoes?
Answer:
Other physical properties, such as the melting temperature of iron or the freezing temperature of water, can only be observed as matter undergoes a physical change. ... In each of these examples, there is a change in the physical state, form, or properties of the substance, but no change in its chemical composition.
Explanation:
i hope this helps :)
what happens to a rock that has rainwater entering its cracks and then freezing
Answer:
Physical weathering is caused by the effects of changing temperature on rocks, causing the rock to break apart.
Explanation:
Freeze-thaw occurs when water continually seeps into cracks, freezes and expands, eventually breaking the rock apart.
The temperature and pressure both increased when you decreased the volume of the container.
O True
O False
Compare and contrast cations and anions and give an example of each.
Cations are positively charged particles while anions are negatively charged particles. They both have different forces therefore they are attract each other.
What is cation ?
Positively charged ions are known as cations. Negatively charged ions are referred to as anions. A charged atom or molecule is an ion. A balanced atom will become a positively charged cation if it loses one or more electrons.
An ion that has lost one or more electrons and now has a net positive charge is said to be a cation. The cation of an atom is smaller than the neutral atom because one or more electrons are taken out to produce a cation.
As an electron donor, the cathode has the potential to initiate reduction. Positive ions from the solution will be drawn to the negatively charged electrode by its charge. It can provide some of the extra electrons it has to these cations or other species in the electrolyzing liquid.
Thus, Cations and anions both have different forces therefore they are attract each other.
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Brittleness
Hardness
Elasticity
Conductivity
Biodegradability
1. Ability to break easily.
2. Ability to decomposed by microorganism.
3. Ability to let the heat and electricity to pass through.
4. Ability to be stretched and return to its original shape.
5. Ability to resist pressure that may cause deformation.
Answer:
BrittlenessBiodegradableConductivityElasticityHardnessCan I get BRAINLIEST.... Please
Which of the following would be the
best tool to use when heating substances
for experiments?
A cardboard boxes
B. plastic beakers
C plastic test tubes
D. glass beakers
2. Calculate the de Broglie wavelength of an electron moving at 1/137th the speed
of light. (At this speed, the relativistic correction to the mass is negligible
Explanation:
speed of light is 3×10^8 m/ s
1/137 of 3 × 10^ 8 m/s ( u get the speed the electron was moving with)
mass of electron 9.109× 10^-31 kg( i think we consider the mass of electron if the relativistic correction of the mass is negligible)
then from de Broglie wavelength= h/ mv
h is planck constant 6.626 × 10^-34
substitute the valies and you get the answer
am sorry I don't have my calculator with me I wuld hv written the answer bt I hope this helps
The de Broglie wavelength of an electron moving at 1/137th the speed of light is 0.24 × 10¹¹m.
What is de Broglie wavelength ?The term de Broglie wavelength defined as the wavelength (λ) that is associated with an object in relation to its momentum and mass.
De Broglie wavelength is mostly represented by the symbol λ or λdB. For a particle with momentum p, the de Broglie wavelength is known as λdB = hp. where h is the Planck constant.
The speed of light = 3×10^8 m/ s
1 / 137 × 3 × 10^ 8 m/s
The mass of electron 9.109× 10^-31 kg
then from de Broglie wavelength
= h / mv
Where,
h is Planck constant 6.626 × 10^-34
substitute the values in above equation
We get,
= 6.626 × 10⁻³⁴ / 9.109 × 10⁻³¹ × 3×10⁸
= 0.24 × 10¹¹m
Thus, The de Broglie wavelength of an electron moving at 1/137th the speed of light is 0.24 × 10¹¹m.
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The energy change in an endothermic reaction is:
A. Internal
B. Positive
C. External
D. Negative
Thank you so much for helping !
The energy change in an endothermic reaction is internal. Hence, option A is correct.
What is an endothermic reaction?Endothermic reactions are chemical reactions in which the reactants absorb heat energy from the surroundings to form products.
A reaction or process in which heat is transferred to a system from its surroundings is endothermic.
The first law of thermodynamics states that the energy of the universe is constant.
The change in the internal energy of a system is the sum of the heat transferred and the work done.
Hence, option A is correct.
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