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
Ulleksa [173]
3 years ago
12

Tamara is doing a scientific investigation to answer the question, "Do corn seeds germinate faster at warmer temperatures than t

hey do at cooler temperatures?" In Tamara's experiment, which variables need to be held constant?
Chemistry
1 answer:
sashaice [31]3 years ago
8 0

Answer:

The tools/instruments, the type of seed, the soil or planting products, the amount of germination time/days, and where the seedling is placed.

Explanation:

If anything but the temperature is changed, it can result in false results. For instance, if Tamera uses red corn for one but yellow corn for the other, it can change the germination rate. So can the type of soil, water or the amount of time each plant has to grow. If she changes thermometers or any other tool she uses, it may give her a different result than the ones she used before. And finally, if she moves the warm plant from the windowsill to her bedroom, it can mess with the results she gets from the heated sample.

You might be interested in
How many grams of KOH do we need to make 250.0ml of a 0.75 M
ZanzabumX [31]

Answer:

10.52g KOH

Explanation:

250.0 ml X 1L/1000ml X 0.75 mol KOH/1L X 56.105gKOH/1 mol KOH =10.52g KOH

5 0
3 years ago
Infer that if all atoms contain the same subatomic particles, what makes the atoms of different elements different?
lbvjy [14]
They aren’t the same atoms.
6 0
3 years ago
Read 2 more answers
According to Le Chatelier’s principle, what happens when the concentration of reactants is doubled in a chemical reaction that w
Usimov [2.4K]
If more reactant is added, the equation will shift to the right in order to make more product (which will increase the products)
3 0
3 years ago
Read 2 more answers
How many grams of copper (II) hydroxide can be prepared from 2.4 grams of copper (II) nitrate (Cu(NO3)2 ) and excess sodium hydr
andreyandreev [35.5K]

Answer:

percentage yield = 67%

Explanation:

Mass of Cu(NO₃)₂  = 15.25 g

Mass of NaOH   = 12.75 g

Percentage yield = ?

Solution:

Cu(NO₃)₂ + 2NaOH   →  Cu(OH)₂ + 2NaNO₃

Moles of Cu(NO₃)₂:

Number of moles = mass/ molar mass

Number of moles = 15.25 g /187.56 g/mol

Number of moles = 0.08 mol

Moles of NaOH :

Number of moles = mass/ molar mass

Number of moles = 12.75 g / 40 g/mol

Number of moles = 0.32 mol

Now we will compare the moles of Cu(OH)₂ with NaOH and Cu(NO₃)₂.      NaOH             :      Cu(OH)₂

                               2                   :          1

                               0.32              :           1/2×0.32 = 0.16 mol

                            Cu(NO₃)₂         :           Cu(OH)₂

                                  1                  :               1

                             0.08                :              0.08

The number of moles produced by  Cu(NO₃)₂  are less so it will limiting reactant.

Mass of Cu(OH)₂:

Mass = number of moles × molar mass

Mass = 0.08 mol × 97.6 g/mol

Mass = 7.808 g

Theoretical yield = 7.808 g

Percent yield:

percentage yield = Actual yield/ theoretical yield ×  100

percentage yield = 5.23 g/  7.808 g ×  100

percentage yield = 0.67 ×  100

percentage yield = 67%

5 0
3 years ago
The atomic symbol Superscript 206 subscript 82 upper P b. represents lead-206 (Pb-206), an isotope that has 82 protons and 124 n
Serggg [28]

Answer:

\left \{ {{y=206} \atop {x=82}}Pb \right.

Explanation:

isotopes are various forms of same elements with different atomic number but different mass number.

Radioactivity is the emission of rays or particles from an atom to produce a new nuclei. There are various forms of radioactive emissions which are

  • Alpha particle emission  \left \{ {{y=4} \atop {x=2}}He \right.
  • Beta particle emission    \left \{ {{y=0} \atop {x=-1}}e \right.
  • gamma radiation             \left \{ {{y=0} \atop {x=0}}γ \right.

in the problem the product formed after radiation was Pb-206. isotopes of lead include Pb-204, Pb-206, Pb-207, Pb-208. they all have atomic number 82. which means the radiation cannot be ∝ or β since both radiations will alter the atomic number of the parent nucleus.

Only gamma radiation with \left \{ {{y=0} \atop {x=0}}γ \right. will produce a Pb-206 of atomic number 82 and mass number 206 , since gamma ray have 0 mass and has 0 atomic number.equation is shown below

\left \{ {{y=206} \atop {x=82}}Pb\right ⇒ \left \{ {{y=206} \atop {x=82}}Pb\right +  \left \{ {{y=0} \atop {x=0}}γ\right.

Thus the atomic symbol is \left \{ {{y=206} \atop {x=82}}Pb\right

8 0
3 years ago
Read 2 more answers
Other questions:
  • Lipid molecules are made up of long chains of hydrogen and __________? a) sulfur b) nitrogen c)carbon d)oxygen
    6·2 answers
  • Which requirement is essential for any of the chemical process that occur in cells to take place
    9·1 answer
  • Advances in medical technology and healthcare have increased the life expectancy of people around the world. What negative effec
    11·1 answer
  • Hi! could you help with this (Brainlist + 50 points)
    5·1 answer
  • A person uses 770 kcal on a long hike. Calculate the energy used for the hike in each of the following energy units.
    9·1 answer
  • Briefly outline a procedure you could use to determine the hc2h3o2 concentration in a vinegar sample
    8·1 answer
  • Which substance particle will be attracted by a positively charged object
    6·1 answer
  • What is true of a solution of 2.0 M NaCl(aq)? (3 points)
    15·1 answer
  • A student wrote The Following hypothesis if more salt is added to a hypothesis
    11·1 answer
  • NO BOTS!<br> Determine the total net force and the direction of movement for the situation.
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!