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padilas [110]
4 years ago
5

The use of more advanced tools made of stone, wood, and bone, such as the ones illustrated below, was typical of which period of

human history?
a. Paleolithic era
b. Neolithic era
c. Bronze Age
d. Iron Age
Chemistry
1 answer:
Sedbober [7]4 years ago
6 0
Paleolithic Era
During the Paleolithic Era, early humans used mostly stone tools but at times also used wood or bone tools.
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A 45 L container holds 28 moles of gas at a temperature of 215 K. What is the pressure
snow_lady [41]

Answer:

The pressure inside the container is 11 atm

Explanation:

We use the formula;

PV=nRT ---> P= nRT/V

P= 28 mol x 0,082 l atm/K mol x 215 K/45 L

<em>P=10,96977778 atm</em>

8 0
3 years ago
A given way isotopes of nitrogen (N) contains 7 electrons,7 protons and 8 neutrons.
Murljashka [212]
Mass number is
protons + nuetrons
So,
7 + 8 = 15
——-
Atomic number is the number of protons
so,
7
3 0
3 years ago
The label on a ready-to-eat cereal box indicates that 1 cup contains 32 grams of carbohydrate, 4 grams of protein, and 2 grams o
eduard

Energy given by carbohydrates present in one cup =32 g * \frac{4 kcal}{1 g} = 128 kcal

Energy given by proteins present in one cup = 4 g * \frac{4 kcal}{1 g} = 16 kcal

Energy given by fat in one cup = 2 g * \frac{9 kcal}{1 g} = 18 kcal

Total energy in one cup of cereal box = 128 kcal + 16 kcal + 18 kcal = 162 kcal

Energy present in two cups = [tex] 2 cups * \frac{162 kcal}{1 cup} *

= 324 kcal

6 0
4 years ago
How many grams of water are made from the reaction of 4.0 grams of hydrogen gas with the given reaction 2H2+O2---&gt;2H2O
Sergeeva-Olga [200]

Answer:

The mass of water is 36 g.

Explanation:

Mass of hydrogen = 4 g

Mass of water = ?

Solution:

First of all we will write the balance chemical equation:

2H₂ + O₂  →  2H₂O

Number of moles of hydrogen = mass / molar mass

Number of moles of hydrogen = 4 g/ 2 g/mol

Number of moles of hydrogen = 2 mol

Now we compare the moles of water with hydrogen from balance chemical equation.

                               H₂     :     H₂O

                                2      :       2

Mass of water = moles × molar mass

Mass of water =  2 mol × 18 g/mol

Mass of water =  36 g

If the water oxygen is in excess than mass of water would be 36 g.

4 0
3 years ago
What phase is not part of mitosis and is where the cells spends most of its time
andriy [413]

Answer:

interphase

Explanation:

they spend most time in interphase

5 0
3 years ago
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