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NikAS [45]
2 years ago
12

Number the events from earliest (1) to most recent (6) to outline the development of the cell theory. Anton van Leeuwenhoek obse

rved small organisms he called “animalcules.” Robert Hooke was the first to use the word “cell.” Matthias Schleiden theorized that plants are made of cells. Theodor Schwann theorized that animals are made of cells. Hans and Zacharias Janssen created the first microscope. Rudolf Virchow theorized that cells come from other pre-existing cels
Chemistry
2 answers:
Ne4ueva [31]2 years ago
4 0
I agree with the answer she provided
adelina 88 [10]2 years ago
3 0

1.Hans and Zacharias Janssen created the first microscope.

2.Robert Hooke was the first to use the word “cell.”

3.Anton van Leeuwenhoek observed small organisms he called “animalcules.”

4.Matthias Schleiden theorized that plants are made of cells.

5.Theodor Schwann theorized that animals are made of cells.

6.Rudolf Virchow theorized that cells come from other pre-existing cells.

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All amino acids that are found in proteins, except for proline, contain a(n); Group of answer choices amino group carbonyl group
Jobisdone [24]

Answer:

amino group

Explanation:

There are twenty (20) amino acids in nature. Generally, each amino acid is structurally made up of a central carbon atom called alpha carbon attached to a hydrogen, carboxylic acid group (-COOH) and an amine group (-NH2). However, one particular amino acid called PROLINE posseses an exception to this.

Proline, which is the only cyclic amino acid, is also the only amino acid that forms a secondary amine group i.e. loss of hydrogen atoms in its amine group when in a protein structure. This means that when in a protein, PROLINE does not have an AMINE GROUP.

7 0
2 years ago
When a 3.22 g sample of an unknown hydrate of sodium sulfate, na2so4 ⋅ h2o(s), is heated, h2o (molar mass 18 g) is driven off. T
Mariana [72]

The value of X is 10 hence the formula of unknown hydrate   sodium sulfate is  NaSO4.10 H20

calculation

step 1:find the moles of NaSO4 and the moles of H2O

moles= mass/molar mass

moles of Na2SO4=1.42÷142=0.01 moles

moles of H20=  mass of H2O/molar mass of H2O

mass of H2O= 3.22-1.42=1.8g

mole of H2O is therefore 1.8÷18=0.1 moles

step 2: find the mole ratio by dividing each mole by smallest number of mole (0.01)

that is Na2So4= 0.01/0.01 =1

            H2O= 0.1/0.01=10

6 0
1 year ago
Enter the correct answer for each unit conversion.
Luden [163]

Answer:

50 mm

4 ft

36 ft

250 cm

1 L

Explanation:

Centimeter to  millimeter:

1 cm is equal to 10 mm.

5cm× 10 mm/1 cm

50 mm

Inches to feet conversion:

1 foot is equal to 12 inches.

48 inch ×  1 feet /12 inch

4 feet

Yard to Feet conversion:

1 yard is equal to 3 feet.

12 yd × 3 ft / 1 yd

36 ft

Meter to centimeter:

One meter is equal to 100 cm.

2.5 m × 100 cm / 1m

250 cm

Milliliter to Liter:

One L is equal to 1000 mL.

1000 mL = 1 L

4 0
1 year ago
Read 2 more answers
Complete combustion of a compound containing hydrogen and carbon produced 2.641 g of carbon dioxide and 1.442 grams of water as
klio [65]

  The empirical   formula  of hydrocarbon is C₃H₈

The  molecular formula of hydrocarbon   is C₆H₁₆


<u><em> Empirical  formula  calculation</em></u>

Hydrocarbon  contain  carbon and hydrogen

  Step 1:  find the  mass  carbon (C) in carbon dioxide (CO₂)  and hydrogen (H )  in water

mass of  of element = molar mass  of element/ molar mass molecule x total mass of    molecule

From periodic table the molar mass  of C =12,    for CO₂ = 12+( 16 x2) =44 g/mol,     for H = 1.00 g/mol,    for H₂O = (2 x1)+16 = 18 g/mol

mass of C = 12/44 x 2.641 =0.7203 g

since there are 2 atom  of H in H₂O the molar mass of H = 1 x2 = 2 g/mol

mass of H  is therefore =  2/18 x 1.442 =0.1602 g


Step 2:  find the moles of C and H

moles = mass÷ molar mass

moles of C = 0.7203 g÷ 12 g/mol = 0.060  moles

moles of H  =  0.1602÷ 1 g/mol = 0.1602 moles


Step 3: find the mole ratio  of C and H by dividing  each  mole by smallest mole ( 0.06)

for C = 0.06/0.06 =1

  For H = 0.1602/0.06 =2.67

multiply   by 3  to remove the decimal

For C = 1 x3 =3

For H = 2.67 x3 =8

therefore the empirical formula = C₃H₈


<u><em>The molecular formula calculation</em></u>

[C₃H₈]n  = 88.1 g/mol

[12 x 3)+( 1 x8)]n =88.1 g/mol

44 n = 88.1

divide both side by 44

n=2

therefore [C₃H₈]₂   = C₆H₁₆



7 0
1 year ago
Read 2 more answers
To prepare a 2 M solution of potassium nitrate (KNO3), which quantities must be measured? The mass of the and the volume of the
Olin [163]

Answer:

The mass of the solute and the volume of the solution.

Explanation:

Hello,

In this case, given the formula of molarity:

M=\frac{n_{solute}}{V_{solution}}

In such a way, since the moles could not be directly measured, we must measure the mass of the solute and by using its molar mass, one could compute its moles. Moreover, since the solution is composed by the solvent (typically water) and the solute, we consequently must measure the volume of the solution needed for the preparation of such concentration-known solution. In such a way, we can actually prepare the required solution.

Best regards.

4 0
2 years ago
Read 2 more answers
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