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3 years ago

How Earth and the sun move in space relative to each other

Chemistry

1 answer:

liberstina [14]3 years ago

6 0

The two theories were:

1.Geocentric theory stating that earth is the centre of the universe and sun revolves around it.

2.Heliocentric theory stating that the earth revolves around the sun.

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A sample of gas has a pressure of 47.5 mm in a 125-ml flask. the sample is transferred to a new flask, where it has a pressure o

Lilit [14]

P1v1=p2v2
47.5*125=66.2*v2
v2= p1v1/p2
=(47.5)(125)/(66.2)
=89.69ml

4 0

3 years ago

How many grams are there in 3.4 x 10^24 atoms of He?

Lelechka [254]

Given :

Number of He atoms, $n = 3.4\times 10^{24}$ atoms.

To Find :

How many grams are their in given number of He atoms.

Solution :

We know, molecular mass of He is 4 g. It means that their are $6.022 \times 10^{23}$ atoms in 4 g of He.

Let, number of gram He in $3.4\times 10^{24}$ atoms is x , so :

$x = \dfrac{3.4\times 10^{24}}{6.022\times 10^{23}}\times 4\\\\x = $$22.58\ g$

Therefore, grams of He atoms is 22.58 g .

5 0

3 years ago

Calculate the percent composition by mass of the following compounds that are important starting materials for synthetic polymer

notsponge [240]

Answer:

C₃H₄O₂ → 50% C; 5.5 % H; 44.5% O

C₄H₆O₂ → 56 % of C; 7 % of H; 37% of O

C₃H₃N → 68 % of C; 6 % of H; 26 % of N

Explanation:

We determine the molar mass of each compound:

C₃H₄O₂ → 72 g/mol

In 1 mol of acrylic acid (72 g), we have:

3 moles of C → 12 g/mol . 3 mol = 36 g of C

4 moles of H → 1 g/mol . 4 mol = 4 g of H

2 moles of O → 16g/mol . 2 mol = 32 g of O

Then in 100 g of salt, we may have:

100 . 36 / 72 = 50 % of C

4 . 100 / 72 = 5.5 % of H

32 . 100 / 72 = 44.5 % of O

C₄H₆O₂ → 86 g/mol

In 1 mol of methyl acrylate (86 g), we have:

4 moles of C → 12 g/mol . 4 mol = 48 g of C

6 moles of H → 1 g/mol . 6 mol = 6 g of H

2 moles of O → 16g/mol . 2 mol = 32 g of O

Then in 100 g of salt, we may have:

100 . 48 / 86 = 56 % of C

6 . 100 / 86 = 7 % of H

32 . 100 / 86 = 37 % of O

C₃H₃N → 53 g/mol

In 1 mol of acrylonitrile (53 g), we have:

3 moles of C → 12 g/mol . 3 mol = 36 g of C

3 moles of H → 1 g/mol . 3 mol = 3 g of H

1 mol of N → 14g/mol . 1 mol = 14 g of N

Then in 100 g of salt, we may have:

100 . 36 / 53 = 68 % of C

3 . 100 / 53 = 6 % of H

14 . 100 / 53 = 26 % of N

3 0

3 years ago

6th grade science . :((

Nadusha1986 [10]

Answer:

C- private

Explanation:

This event seems to be exclusive. That is why it is private.

3 0

3 years ago

SOVA2 [1]

This problem is providing us with the recommended maintenance dose of penicillin for children as 1.0 mg/kg/hr by injection. Thus, the delivery rate for a 40-pound child is required, if 10 mL of a 25 mg/mL solution of penicillin is added to a 100-mL bottle of saline. At the end, the result is 8.0 mL/hr:

<h3>Dimensional analysis:</h3>

In chemistry, dimensional analysis allows us to obtain a specific result given relevant information about it. Although a formula is not always provided, one can use the units as a reference for the calculations.

For example, this problem asks for the rate, in mL/hr, at which a child gets this dose, so the first step will be to get the mass of the child in kilograms:

$40 lb*\frac{0.4536kg}{1lb}= 18.144kg$