answer.
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
dedylja [7]
1 year ago
11

Which of the following tools could have become cross-contaminated during the experiment if you had not cleaned them carefully be

tween successive tests?
A. Spoon

B. Beaker

C. Stirring Rod

D. Graduated Cylinder

E. Distilled water in a spray bottle
Chemistry
2 answers:
guajiro [1.7K]1 year ago
8 0

Answer:

A. Spoon, B. Beaker, C. Stirring Rod, D. Graduated Cylinder

Explanation:

Elanso [62]1 year ago
3 0

Explanation:

When we are using spoon, beaker, stirring rod and graduated cylinder then they directly come in contact with the chemical we are using. Hence, if they are not washed thoroughly then chemicals remain deposited over them.

As a result, when successive test are performed using the same contaminated apparatuses then we do not get the desired results.

Whereas distilled water in a spray bottle if poured without touching or coming in contact with any kind of chemicals.

Hence, we can conclude that spoon, beaker, stirring rod and graduated cylinder are the tools that could have become cross-contaminated during the experiment if you had not cleaned them carefully between successive tests.

You might be interested in
In the activity, click on the E∘cell and Keq quantities to observe how they are related. Use this relation to calculate Keq for
joja [24]

Answer:

ΔG° = -118x10³ J/mol

Explanation:

The two half-reactions in the cell are:

Oxidation half-reaction:

Co(s) → Co²⁺(aq) + 2e⁻; E° = -0,28V

Reduction half-reaction:

Cu²⁺(aq)+2e⁻ → Cu(s); E° = 0,34V

The E° of the cell is defined as:

E_{cell} = E_{red} - E_{ox}

Replacing:

0,34V - (-0,28V) = 0,62V

It is possible to obtain the keq from E°cell with Nernst equation thus:

nE°cell/0,0592 = log (keq)

Where:

E°cell is standard electrode potential (0.62 V)

n is number of electrons transferred (2 electrons, from the half-reactions)

Replacing:

0,62V×2/0,0592 = log (keq)

20,946 = log keq

keq = 8,83x10²⁰≈ 5,88x10²⁰

ΔG° is defined as:

ΔG° = -RT ln Keq

Where R is gas constant (8,314472 J/molK) and T is temperature (298K):

ΔG° = -8,314472 J/molK×298K ln5,88x10²⁰

<em>ΔG° = -118x10³ J/mol</em>

<em />

I hope it helps!

8 0
2 years ago
A solution is prepared by diluting 50.00 ml of 2.575 m solution of hno3 to 250.0 ml. what is the molarity of the resulting solut
larisa [96]
Thank you for posting your question here at brainly. Below are the choices that can be found elsewhere:

12.88 M 
<span>0.1278 M </span>
<span>0.2000 M </span>
<span>0.5150 M
</span>
Below is the answer:

<span>5 times diluted (250/50),so 2.575/5=0.515 M
</span>
I hope it helps. 
8 0
1 year ago
Read 2 more answers
Complete this sentence. If volume remains the same while the mass of a substance ________, the density of the substance will____
anygoal [31]
If volume remains the same while the mass of a substance increases, the density of the substance will increase.
So if the volume remains the same while the mass of a substance decreases, the density of the substance will decrease, too.
8 0
1 year ago
Read 2 more answers
A 74.0-gram piece of metal at 94.0 °C is placed in 120.0 g of water in a calorimeter at 26.5 °C. The final temperature in the ca
disa [49]

Answer:

Explanation:

Heat lost by metal = mass x specific heat x fall in temperature

= 74 x S x ( 94 - 32 )

= 4588 S

heat gained by water = mass x specific heat x rise in temperature

= 120 x 1 x ( 32 - 26.5 )   ( specific heat of water is 1 cals / gm )

= 660

Heat lost = heat gained

4588S = 660

S = .14 cal /gm .

Specific heat of metal = .14 cal  / gm

7 0
1 year ago
A student performed an analysis of a sample for its calcium content and obtained the following results:
sweet-ann [11.9K]

Answer:

14.9075 g, 28.67%, 0.11%

Explanation:

The mean concentration of calcium = summation x / frequency

= ( 14.92 + 1491 + 14.88 + 14.92 ) /4 = 14.9075 g

Standard deviation = √(summation (x - μ)² /n) = √ ( ((14.92 - 14.9075)² +(14.91 - 14.9075)² + (14.88 - 14.9075)² + ( 14.92 - 14.9075)²) / 4) = 0.0164

b)  percent error = abs(14.9075 - 20.90) / 20.90 × 100 = 28.67%

c) relative standard deviation = standard deviation / mean × 100 = 0.0164 /  14.9075 × 100 = 0.11%

d) The accuracy of the measure is the measurement compared to the actual which according to the standard set by the instructor (5%error) is not very accurate because the percent error is high (28.67%) while the relative standard deviation is quite low ( 0.11%) which means the measurement precision is very high.

The student will have to redo the experiment because the experiment was not too accurate since the percent error is way higher than the set value (5%) although the precision was high.

5 0
2 years ago
Other questions:
  • Which of the following energy sources obtains its energy from gravitational potential energy?
    6·1 answer
  • When 12 moles of o2 react with 1.1 mole of c10h8 what is the limiting reactant?
    5·2 answers
  • A reaction produces 92.50 g FeSO4. How many grams of CuSO4 are necessary for this to occur?
    10·2 answers
  • In the manufacture of paper, logs are cut into small chips, which are stirred into an alkaline solution that dissolves several o
    8·2 answers
  • suppose that during the icy hot lab that 65 kj of energy were transferred to 450 g of water at 20 C. What would have been the fi
    12·1 answer
  • Phthalic acid is a diprotic acid having the formula HO2CC6H4CO2H that can be converted to a salt by reaction with base. Which of
    8·1 answer
  • A small portion of a crystal lattice is sketched below. What is the name of the unit cell of this lattice? Your answer must be a
    9·1 answer
  • Which of the following pairs of compounds can you directly compare against each other theoretically? (choose all that apply) (hi
    13·1 answer
  • How many mg does a 643 kg sample contain?
    7·1 answer
  • Determine the overall charge on particles with the subatomic makeups given.
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!