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3 years ago

Can some help me plz.

Chemistry

1 answer:

tankabanditka [31]3 years ago

6 0

Answer:

Pythagoras was the first ancient astronomer to suggest that there was a harmony of the spheres, and that the movement of the planets, sun, moon and stars could be described by whole numbers and mathematical precision. His other discovery was that the morning and evening star are the same thing, the planet Venus.

Explanation:

if im right plz give me brainliest !! :)

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Which organelle is the control center of a cell?

Korvikt [17]

C) the nucleus. Hope this helps :)

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3 years ago

Read 2 more answers

The relationship between pressure and volume, when moles and temperature of a gas are held constant, is: PV = k. We could say th

pochemuha

You can say that if the volume of the gas is halved, the pressure is doubled.

The expression shows that pressure and volume are inversely proportional if temperature and amount of gas is held constant. This means that if volume goes down the pressure needs to go up. That also means that in order to maintain the K value, if pressure is doubled the volume needs to be halved and if the pressure is halved the volume needs to be doubled.

This relationship only works if we assume everything else (Temperature and moles of gas) to be constant.

7 0

4 years ago

PLEASE ANSWER, I WILL GIVE BRAINLIEST AND THANKS!

zheka24 [161]

Answer:

Mass = 8 g

Explanation:

Given data:

Mass of MgO formed = 20 g

Mass of oxygen needed = ?

Solution:

Chemical equation:

2Mg + O₂ → 2MgO

Number of moles of MgO:

Number of moles = mass/molar mass

Number of moles = 20 g/ 40 g/mol

Number of moles = 0.5 mol

Now we will compare the moles of MgO and O₂ from balance chemical equation:

MgO : O₂

2 : 1

0.5 : 1/2×0.5 = 0.25 mol

Mass of oxygen required:

Mass = number of moles × molar mass

Molar mass of O₂ is 32 g/mol

Mass = 0.25 mol × 32 g/mol

Mass = 8 g

4 0

3 years ago

__________, a colligative property, is the difference between the freezing temperature of a pure solvent and the freezing point

PilotLPTM [1.2K]

Freezing-point depression.

8 0

3 years ago

1. If there are 100 navy beans, 27 pinto beans and 173 blackeyed peas in a container, what is the percent abundance in the conta

kompoz [17]

The answers to the two questions are:

1. The percent abundance in the container which has 100 navy, 27 pinto, and 173 black-eyed peas beans is 33.3%, 9.0%, and 57.7% for navy bean, pinto bean, and black-eyed peas beans, respectively.

2. The weighted average score for the scores of 85, 75, 96 obtained from the evaluations of exams (20%), labs (75%), and homework (96%) is 84.1.

1. The percent abundance by type of bean is given by:

$\% = \frac{n}{n_{t}} \times 100$ (1)

Where:

n: is the number of each type of beans

$n_{t}$ : is the total number of beans

The total number of beans can be calculated by adding the number of all the types of beans:

$n_{t} = n_{n} + n_{p} + n_{b}$ (2)

Where:

$n_{n}$ : is the number of navy beans = 100

$n_{p}$ : is the number of pinto beans = 27

$n_{b}$ : is the number of black-eyed peas beans = 173

Hence, the total number of beans is (eq 2):

$n_{t} = 100 + 27 + 173 = 300$

Now, the percent abundance by type of bean is (eq 1):

Navy beans

$\%_{n} = \frac{100}{300} \times 100 = 33.3 \%$

Pinto beans

$\%_{p} = \frac{27}{300} \times 100 = 9.0 \%$

Black-eyed peas beans

$\%_{b} = \frac{173}{300} \times 100 = 57.7 \%$

Hence, the percent abundance by type of bean is 33.3%, 9.0%, and 57.7% for navy bean, pinto bean, and black-eyed peas beans, respectively.

2. The average score (S) can be calculated as follows:

$S = e*\%_{e} + l*\%_{l} + h*\%_{h}$ (3)

Where:

e: is the score for exams = 85

l: is the score for lab reports = 75

h: is the score for homework = 96

$%_{e}$ $\%_{e}$ : is the percent for exams = 70.0%

$\%_{l}$ : is the percent for lab reports = 20.0%

$\%_{h}$ : is the percent for homework = 10.0%

Then, the average score is:

$S = 85*0.70 + 75*0.20 + 96*0.10 = 84.1$

We can see that if the score for each evaluation is 100, after multiplying every evaluation for its respective percent, the final average score would be 100.

Therefore, the weighted average score will be 84.1.

Find more about percents here:

brainly.com/question/255442?referrer=searchResults

brainly.com/question/22444616?referrer=searchResults

I hope it helps you!

4 0

3 years ago