The measurement 0.020 km has two significant figures, which are '2' and '0' after '2'.
The number of significant figures in a number refers to the digits that carry meaning and contribute to the accuracy of the measurement. In the given measurement of 0.020 kilometers, there are two significant figures. These are the digits '2' and '0' located immediately after the '2'.
The zeros before these numbers, such as in '0.020 km', are not significant figures because they simply indicate the position of the decimal point, and they do not contribute to the precision of the measurement.
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Answer:
Heat Energy needed (Q) = 68250 J
Energy lost (Q') = 10500 J
Explanation:
Applying,
Q = cm(t₂-t₁)............. Equation 1
Where Q = heat energy needed, c = specific heat capacity of water, m = mass of water, t₁ = initial temperature, t₂ = final temperature.
From the question,
Given: m = 250 g = 0.25 kg, t₁ = 20.0°C, t₂ = 85.0°C
Constant: c = 4200 J/kg°C
Substitute these values into equation 1
Q = 0.25(4200)(85-20)
Q = 68250 J.
Similarly, heat lost
Q' = cm(t₁-t₂)................. Equation 2
Where Q = heat lost
Given: t₁ = 85°C, t₂ = 75°C
Substitute into equation 2
Q' = 4200(0.25)(85-75)
Q' = 10500 J
square inch, what is the area of her feet in cubic centimeters?
__cm2
The area = 313.612 cm²
Force (F) can cause objects to move
While pressure (P)is the force per unit area
weight=force=105 pounds(lb)⇒english units
pressure = 2.16 lb/in²
Thea are (A)
Answer:
Periods the horizontal rows on the periodic table.
Explanation:
In a modern periodic table elements are arranged increasing number of their atomic numbers.
The horizontal rows known as periods , there are 7 seven periods
In his periodic table, elements lying in the same period have same number of shells around the nucleus.
The vertical columns known as groups, there total 18 groups.
In his periodic table, elements having similar properties lied in the same vertical columns or groups because all the elements had same number of valence electrons.
How many molecules are in 2.47 moles of CC14? *
B- The electrons spend more time around the oxygen atom because oxygen is more electronegative than hydrogen.
C- There is a partial positive charge on each hydrogen atom and two partial negative charges on the oxygen atom in a water molecule.
D- Attractions form between opposite partial charges.
Answer:- Water is an electronegative molecule.
Explanation:
A molecule cannot be electronegative. Rather the atoms in a molecule may be electronegative. This first statement does not account for the hydrogen bonding in water at all because it is incorrect. However, the other statements in the question sheds more light on the nature of hydrogen bonding in water molecule.
Options B, C, and D are correct explanations for why water molecules form hydrogen bonds.
The correct option that does not help to explain why water molecules form hydrogen bonds is A- Water is an electronegative molecule. Hydrogen bonds form between a hydrogen atom in one water molecule and an electronegative atom, such as oxygen or nitrogen, in another water molecule. This attraction occurs because the electronegative atom pulls the shared electrons closer to itself, creating a partial positive charge on the hydrogen atom. The presence of partial positive and negative charges on the molecule is crucial for hydrogen bond formation. Therefore, options B, C, and D all contribute to explaining why water molecules form hydrogen bonds.
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True, Plants don't have brains, but they still adapt to their environments.
Adaptation is a process where they are changing their nature to suit the environment.
We have seen that plants do adaptation according to the environment, as in the summer season their leaves are hanging down but in the rainy season they show blossoms and green leaves. So, according to the environment for the survival and reproduction they adapt their body.
Hence, plants have no brains, but they still adapt.
To learn more about adaptation, visit the below link:
Answer:
True
Explanation:
I just took that last year, and got a100%