1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Maslowich
3 years ago
8

A chemistry instructor provides each student with 8 test tubes at the beginning of the year. If there are 28 students per class,

how many test tubes are required for three chemistry classes?
Chemistry
1 answer:
Ann [662]3 years ago
7 0
Answer :8*28=224
224*3=672
You might be interested in
HELPP ASAPP..........
Ksivusya [100]

Answer:

A, C, D.

Explanation:

6 0
3 years ago
Read 2 more answers
A 99.8 mL sample of a solution that is 12.0% KI by mass (d: 1.093 g/mL) is added to 96.7 mL of another solution that is 14.0% Pb
andre [41]

Answer:

m_{PbI_2}=18.2gPbI_2

Explanation:

Hello,

In this case, we write the reaction again:

Pb(NO_3)_2(aq) + 2 KI(aq)\rightarrow PbI_2(s) + 2 KNO_3(aq)

In such a way, the first thing we do is to compute the reacting moles of lead (II) nitrate and potassium iodide, by using the concentration, volumes, densities and molar masses, 331.2 g/mol and 166.0 g/mol respectively:

n_{Pb(NO_3)_2}=\frac{0.14gPb(NO_3)_2}{1g\ sln}*\frac{1molPb(NO_3)_2}{331.2gPb(NO_3)_2}  *\frac{1.134g\ sln}{1mL\ sln} *96.7mL\ sln\\\\n_{Pb(NO_3)_2}=0.04635molPb(NO_3)_2\\\\n_{KI}=\frac{0.12gKI}{1g\ sln}*\frac{1molKI}{166.0gKI}  *\frac{1.093g\ sln}{1mL\ sln} *99.8mL\ sln\\\\n_{KI}=0.07885molKI

Next, as lead (II) nitrate and potassium iodide are in a 1:2 molar ratio, 0.04635 mol of lead (II) nitrate will completely react with the following moles of potassium nitrate:

0.04635molPb(NO_3)_2*\frac{2molKI}{1molPb(NO_3)_2} =0.0927molKI

But we only have 0.07885 moles, for that reason KI is the limiting reactant, so we compute the yielded grams of lead (II) iodide, whose molar mass is 461.01 g/mol, by using their 2:1 molar ratio:

m_{PbI_2}=0.07885molKI*\frac{1molPbI_2}{2molKI} *\frac{461.01gPbI_2}{1molPbI_2} \\\\m_{PbI_2}=18.2gPbI_2

Best regards.

5 0
3 years ago
Read 2 more answers
Indica, con base en la siguiente ecuación:
Anvisha [2.4K]
Hello I just want to say have a good day
7 0
2 years ago
How does reproduction leads to natural selection in a population
Advocard [28]

Natural selection requires variation between individuals. Mutations and reproduction increase genetic variation in a population. Natural selection occurs when environmental pressures favor certain traits that are passed on to offspring.

6 0
2 years ago
What do the elements in each pair have in common? k, kr be, mg ni, tc b, ge al, pb?
tensa zangetsu [6.8K]
The pairs are:
K, Kr - Same period
Be, Mg - Same group
Ni, Tc - Both are transition metals
B, Ge - Both are metaloids
Al, Pb - Both form inert oxides
4 0
3 years ago
Other questions:
  • If there are no chemical controls which can be implemented at your worksite, what can you do to protect yourself?
    6·1 answer
  • "what is the mole fraction of solute in a 3.87 m aqueous solution?"
    13·3 answers
  • How is a lithium atom (Li) different from a lithium ion (Li+)?
    9·2 answers
  • Name the bleaching agent for cloth​
    9·2 answers
  • Why did improvements in agriculture lead to the growth of cities?
    13·1 answer
  • Determine the temperature of 1.42 mol of a gas contained in a 3.00-L container at a pressure of 123 kPa.
    11·1 answer
  • Two factors that determine whether a reaction will occur spontaneously
    10·1 answer
  • What is an endothermic reaction?
    14·1 answer
  • I’m stuck on number 2
    13·2 answers
  • Match each form of energy with it's definition.
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!