Complete question is;
A drop of water has a volume of approximately 7 × 10⁻² ml. How many water molecules does it contain? The density of water is 1.0 g/cm³.
This question will require us to first find the number of moles and then use avogadro's number to get the number of water molecules.
<em><u>Number of water molecules = 2.34 × 10²¹ molecules</u></em>
We are given;
Volume of water; V = 7 × 10⁻² ml
Density of water; ρ = 1 g/cm³ = 1 g/ml
Formula for mass is; m = ρV
m = 1 × 7 × 10⁻²
m = 7 × 10⁻² g
from online calculation, molar mass of water = 18.01 g/mol
Number of moles(n) = mass/molar mass
Thus;
n = (7 × 10⁻²)/18.01
n = 3.887 × 10⁻³ mol
from avogadro's number, we know that;
1 mol = 6.022 × 10²³ molecules
Thus,3.887 × 10⁻³ mol will give; 6.022 × 10²³ × 3.887 × 10⁻³ = 2.34 × 10²¹ molecules
Read more at; brainly.in/question/17990661
The appropriate answer is a. HUNTER-GATHERER. Hunter-gatherer societies are nomadic and they forage for edible plants, bean, fruits and nuts. They also hunt wild game for food. Early humans in the Neolithic period practiced this way of life.
Agrarian societies thrive on agriculture which they depend on for sustainable and for trade. Animals and plants are domesticated and so people can settle and build a society. Pastoral agriculture is a semi-nomadic lifestyle where the society is centered around keeping herds of grazing animals. Industrial societies focus on manufacturing and this is the backbone of the society.
5 i believe the right answer
Answer:
A chemical change occurred, a gas and precipitate was produced
Explanation:
From the question , we are informed of science lab, where Cash mixes two clear liquids together in a beaker. Bubbles are produced, and a white solid forms and settles to the bottom.
In this case the change that took place is chemical change ( is one where new product are formed after two substance react) the bubbles that is produced signify the presence of gas in the product, white solid formed is reffered to as a precipitate( which is reffered to as solid that is been formed from a particular solution).
