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kumpel [21]
2 years ago
3

In the same science fair, Tina asks the question "Does caffeine increase the heart rate of an earthworm?" In Test 1, she measure

s the heart rate by looking at the earthworm under a microscope, the earthworm has a heart rate of 50 bpm (beats per minute). In Test 2, she places a few drops of caffeine on the earthworm's skin and measures the rate again. In this test, the heart rate is 68 bpm. 6) What is the Independent/Manipulated variable? 7) What is the Dependent/Responding variable? 8) Tina's experiment should have included a hypothesis. In a complete sentence, suggest a hypothesis for Tina's experiment. You may use an if/then statement.
Chemistry
1 answer:
Sedbober [7]2 years ago
5 0

Answer:

Independent variable- effect of caffeine

Dependent variable- heart rate

Hypothesis- If a stimulant such as caffeine is administered to earthworm, then its heart rate increases.

Explanation:

The experiment is based on the research question; "Does caffeine increase the heart rate of an earthworm?" We can see from this research question that the independent variable is the effect of caffeine and the response it produces is a change in the heart rate (the dependent variable)

This now leads us to a hypothesis that states thus; 'If a stimulant such as caffeine is administered to earthworm, then its heart rate increases.'

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What orbitals are used to form the 10 sigma bonds in propane (ch3ch2ch3)? Label each atom with the appropriate hybridization. Dr
SVETLANKA909090 [29]

Mixing of pure orbitals having nearly equal energy to form equal number of completely new orbitals is said to be hybridization.

For the compound, CH_3CH_2CH_3 the electronic configuration of the atoms, carbon and hydrogen are:

Carbon (atomic number=6): In ground state= 1s^{2}2s^{2}2p^{2}

In excited state: 1s^{2}2s^{1}2p^{3}

Hydrogen (atomic number=1): 1s^{1}

All the bonds in the compound is single bond(\sigma-bond) that is they are formed by head on collision of the orbitals.

The structure of the compound is shown in the image.

The Carbon-Hydrogen bond is formed by overlapping of s-orbital of hydrogen to p-orbital of carbon.

In order to complete the octet the required number of electrons for carbon is 4 and for hydrogen is 1. So, the electron in 1s^{1} of hydrogen will overlap to the 2p^{3}-orbital of carbon.

Thus, the hybridization of Hydrogen is s-hybridization and the hybridization of Carbon is sp^{3}-hybridization.

The hybridization of each atom is shown in the image.

3 0
2 years ago
Lithium has an atomic mass of 6.941 amu. Lithium has two common isotopes. The one isotope has a mass of 6.015 amu and a relative
koban [17]

Answer:

The atomic mass of second isotope is 7.016

Explanation:

Given data:

Average Atomic mass of lithium = 6.941 amu

Atomic mass of first isotope = 6.015 amu

Relative abundance of first isotope = 7.49%

Abundance of second isotope = ?

Atomic mass of other isotope = ?

Solution:

Total abundance = 100%

100 - 7.49 = 92.51%

percentage abundance of second isotope = 92.51%

Now we will calculate the mass if second isotope.

Average atomic mass of lithium = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)  / 100

6.941 = (6.015×7.49)+(x×92.51) /100

6.941 =  45.05235 + (x92.51) / 100

6.941×100 = 45.05235 + (x92.51)

694.1 - 45.05235   = (x92.51)

649.04765 = x 92.51

x = 485.583 /92.51

x = 7.016

The atomic mass of second isotope is 7.016

3 0
2 years ago
Why does 4.03/0.0000035 = 1.2 x 106, instead of a different number of significant figures?
jasenka [17]

Explanations:- As per the significant figures rule, In multiplication and division, we go with least number of sig figs.

4.03 has three sig figs where as 0.0000035 has two sig figs only, The zeros in this number are not sig figs as they are just holding the place values. As the least number of sig figs here is two, the answer needs to be reported with two sig figs only.

\frac{4.03}{0.0000035}=1.2*10^6



4 0
2 years ago
A teacher wants to figure out The amount of a solution that is needed for a titration experiment in a class lab! the class has 1
AnnZ [28]
The teacher needs 1500 mL for the whole class.
5 0
2 years ago
Read 2 more answers
True or false, The atomic number of an element is a whole number that decreases as you read across each row of
torisob [31]

Answer:

I believe it's false because the atomic number is the number of protons in the nucleus of an atom.

5 0
2 years ago
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