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Natalija [7]
1 year ago
7

!!!!100 POINTS!!!!

Chemistry
1 answer:
Cerrena [4.2K]1 year ago
6 0

The research of astronomy during the time period of 1970 - 1990 is given below:

<u>Date</u>                                                   <u>Event</u>

1. 15 June 1974               Black Brant VC sounding rocket from White Sands.

2. 14 May 1973              Launch of Skylab, the USA's first space station

3. 26 July 1971           Launch of Apollo 15

<h3>What is Astronomy?</h3>

This refers to the branch of science that deals with celestial bodies and their relation to each other.

Hence, from information about astronomy, between the time period 1970 - 1990 as it was on the 26th of December, 1974 that the Soviet space station Salyut-4 was launched.

The event I think had the greatest impact in astronomical history during this time period was the launch of Apollo 16.

Read more about astronomy here:

brainly.com/question/1141458

#SPJ1

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With white light, a team measured a 0.7% percent change with 3.5g of plant matter in a one liter container. Convert
Strike441 [17]

moles CO₂ = 5.57.10⁻⁴

<h3>Further explanation   </h3>

A mole is a number of particles(atoms, molecules, ions)  in a substance

Can be formulated :

\tt mol=\dfrac{mass}{MW}

0.7% percent change with 3.5g of plant matter

mass :

\tt 0.7\%\times 3.5~g=0.0245~g

moles :

\tt moles=\dfrac{0.0245}{44}=0.000557=5.57.10^{-4}

5 0
3 years ago
15.630 g milk chocolate bar ks found to contain 9.815g of sugar. how many milligrams of sugar does the bar contain?
sleet_krkn [62]
Well there are 1,000 milligrams in 1 gram so 9.815 grams of sugar is equivalent to 9,815 milligrams of sugar. So a bar of milk chocolate contains 9,815 milligrams of sugar.
3 0
3 years ago
Read 2 more answers
Basilosaurus cetoides was a large mammal that existed 35 million years ago. It was 20 m long and had a large skull, incompletely
Korvikt [17]

Answer: hey so I’m taking the same test as you right now. I’m on that question and I searched it up and came on here. Would you mind telling me the answer?

Explanation:

5 0
2 years ago
In one step in the synthesis of the insecticide Sevin, naphthol reacts with phosgene as shown.
Serhud [2]

Answer:

Explanation:

Chemical equation:

C₁₀H₈O + COCl₂  → C₁₁H₇O₂Cl + HCl

A. How many kilograms of C₁₁H₇O₂Cl form from 2.5×10*2 kg of naphthol?

Given data:

Mass of naphthol = 2.5 ×10² kg ( 250×1000 = 250000 g)

Mass of C₁₁H₇O₂Cl = ?

Solution:

Number of moles of naphthol = mass/ molar mass

Number of moles of naphthol = 250000 g/ 144.17 g/mol

Number of moles of naphthol = 1734.1 mol

Now we will compare the moles of naphthol with C₁₁H₇O₂Cl.

                     C₁₀H₈O       :         C₁₁H₇O₂Cl

                        1               :                1

                       1734.1         :             1734.1

Mass of C₁₁H₇O₂Cl:

Mass = number of moles × molar mass

Mass = 1734.1 mol × 206.5 g/mol

Mass = 358091.65 g

Gram to kilogram:

1 kg×358091.65 g/ 1000 g  = 358.1 kg

B. If 100. g of naphthol and 100. g of phosgene react, what is the theoretical yield of C11H7O2Cl?

Given data:

Mass of naphthol = 100 g

Mass of COCl₂ = 100 g

Theoretical yield of C₁₁H₇O₂Cl = ?

Solution:

Number of moles of naphthol:

Number of moles of naphthol = mass/ molar mass

Number of moles of naphthol = 100 g/ 144.17 g/mol

Number of moles of naphthol = 0.694 mol

Number of moles of phosgene:

Number of moles  = mass/ molar mass

Number of moles =  100 g/ 99 g/mol

Number of moles = 1.0 mol

Now we will compare the moles of naphthol and phosgene with C₁₁H₇O₂Cl.

                     C₁₀H₈O        :         C₁₁H₇O₂Cl

                        1                :                1

                       0.694        :              0.694

                    COCl₂          :             C₁₁H₇O₂Cl

                        1                :                1

                       1.0              :              1.0

The number of moles of C₁₁H₇O₂Cl produced by C₁₀H₈O are less so it will limiting reactant and limit the yield of  C₁₁H₇O₂Cl.

Mass of C₁₁H₇O₂Cl:

Mass = number of moles × molar mass

Mass =  0.694 mol × 206.5 g/mol

Mass = 143.3 g

Theoretical yield  =  143.3 g

C. If the actual yield of C11H7O2Cl in part b is 118 g, what is the percent yield?

Given data:

Actual yield of C₁₁H₇O₂Cl = 118 g

Theoretical yield = 143.3 g

Percent yield = ?

Solution:

Formula :

Percent yield = actual yield / theoretical yield × 100

Now we will put the values in formula.

Percent yield = 118 g/ 143.3 g × 100

Percent yield = 0.82 × 100

Percent yield = 82%

5 0
2 years ago
When comparing Potassium (K) and Calcium (Ca) you must compare?
Rom4ik [11]
Vitamin K and potassium are essential micronutrients the body needs to develop and function properly. The two share some things in common, but they’re not the same.

Each has a unique set of properties and purposes. Unlike vitamin K, potassium is not a vitamin. Rather, it’s a mineral.

On the periodic table, the chemical symbol for potassium is the letter K. Thus, people sometimes confuse potassium with vitamin K.

This article highlights some of the main similarities and differences between vitamin K and potassium.
8 0
2 years ago
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