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Nastasia [14]
3 years ago
11

4. The blood vessels, heart and the blood make up

Chemistry
2 answers:
Ratling [72]3 years ago
8 0

Answer:

D, the cardiovascular system

Explanation:

The Cardiovascular System is the system at which blood circulates through our body

andrew-mc [135]3 years ago
3 0
D): the cardiovascular system because the blood vessels, heart and blood make up that system
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A company produces a colorless vinegar that is 5.0% HC2H3O2 in water. Using thymol blue as an indicator, a student titrates a 15
Nataly_w [17]

The negative ion in aqueous sodium hydroxide, NaOH(aq) is hydroxide ion, OH-.

<h3>What is a neutralization reaction?</h3>

A neutralization reaction is a reaction between an acid and a base to form salt and water only.

The reaction between vinegar and NaOH is a neutralization reaction which produces a salt and water only.

NaOH is composed of a positive sodium ion, Na+ and a negative hydroxide ion, OH-

Therefore, the negative ion in the NaOH(aq) used in this titration is hydroxide ion, OH-.

Learn more about hydroxide ion at: brainly.com/question/3078877

6 0
2 years ago
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Vitek1552 [10]
2C4H10 + 13O2 -> 8CO2 + 10H2O
5 0
3 years ago
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A student reacts 0.600 g of lead (ii) nitrate with 0.850 g of potassium iodide
Fynjy0 [20]
Q1)
the reaction that takes place is 
lead nitrate reacting with potassium iodide to form lead iodide and potassium nitrate 
balanced chemical equation for the reaction is as follows
Pb(NO₃)₂ + 2KI ----> PbI₂  + 2KNO₃

Q2)
mass of lead nitrate present - 0.600 g 
number of moles = mass present / molar mass 
number of moles - 0.600 g / 331.2 g/mol = 0.00181 mol 

Q3)
mass of potassium iodide present - 0.850 g
number of moles = mass present / molar mass
number of moles of potassium iodide = 0.850 g / 166 g/mol = 0.00512 mol

Q4)
we have to calculate the number of moles of PbI₂ formed based on the number of moles of Pb(NO₃)₂ present assuming the whole amount of Pb(NO₃)₂ was used up 
stoichiometry of Pb(NO₃)₂ to PbI₂ is 1:1
number of Pb(NO₃)₂ moles reacted - 0.00181 mol
therefore number of PbI₂ moles formed - 0.00181 mol 


Q5)
next we have to calculate the number of moles of PbI₂ formed based on the amount of KI moles present , assuming all the moles of KI were used up in the reaction 
stoichiometry of KI to PbI₂ is 2:1
number of moles of KI reacted - 0.00512 mol
then number of moles of PbI₂ formed - 0.00512 x 2 = 0.0102 mol
0.0102 mol of PbI₂ is formed 

Q6)
limting reactant is the reactant that is fully consumed during the reaction. the amount of product formed depends on the amount of limiting reactant present

if lead nitrate is the limiting reactant 
if 1 mol of Pb(NO₃)₂ reacts with 2 mol of KI 
then 0.00181 mol of Pb(NO₃)₂ reacts with - 2 x 0.00181 mol of KI = 0.00362 mol 
but 0.00512 mol of KI is present and only 0.00362 mol are required 
therefore KI is in excess and Pb(NO₃)₂ is the limiting reactant 

Pb(NO₃)₂ is the limiting reactant 

Q7)
then the amount of PbI₂ formed depends on amount of Pb(NO₃)₂ present 
therefore number of moles of PbI₂ formed is based on number of Pb(NO₃)₂ moles present 
as calculated in Question number 4 - Q4
number of PbI₂ moles formed - 0.00181 mol 
mass of PbI₂ formed - 461 g/mol x 0.00181 mol = 0.834 g
mass of PbI₂ formed - 0.834 g

Q8) 
actual yield obtained  is not always equal to the theoretical yield . therefore we have to find the percent yield. This tells us the percentage of the theoretical yield that is actually obtained after the experiment
percent yield = actual yield / theoretical yield x 100 %
percent yield = 0.475 g / 0.834 g x 100 % = 57.0 %
percent yield of lead iodide is 57.0 %
6 0
3 years ago
When optically active (R)-2-methylcyclohexanone is treated with either aqueous base or acid, racemization occurs. Explain.
IrinaK [193]

Answer:

See explanation

Explanation:

Racemization is said to occur when a 1:1 ratio of (+) and (-) enantiomers of a compound are produced in a reaction.

The reaction of optically active (R)-2-methylcyclohexanone with either aqueous base or acid leads to the formation of a planar enol species for reaction with acid and a planar enolate species for reaction with base.

Both reactions involves the formation of achiral species which reverts back to the chiral product with equal chances of the formation of both enantiomers of the product during the process. This leads to racemization of the product in both cases.

3 0
3 years ago
20) Pythagorean Theorem
Elan Coil [88]

i think  its a

Explanation:

3 0
3 years ago
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