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2 years ago

True/False: Animal embryos look similar early in development because all animals share a common ancestor.

Chemistry

2 answers:

user100 [1]2 years ago

8 0

You should go on yahoo answers and ask it! Someone will get back to you

sweet-ann [11.9K]2 years ago

7 0

Answer:

True

Explanation:

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Calculate the percent by mass of 4.35g of Na I dissolved in 105g of water

Ludmilka [50]

We are given:

Mass of Na added = 4.35 grams

Mass of water = 105 grams

Mass Percent of Na:

Total mass of the solution = mass of solute + mass of solvent

Total mass of the solution = 4.35 + 105 = 109.35 grams

Mass percent of solute = (mass of solute / mass of solution) * 100

Mass percent of Solute = (4.35 / 109.35) * 100

Mass percent = 3.978 %

4 0

2 years ago

A fine of 50.0 mL of 0.0900 M CaCl2 reacts with excess sodium carbonate to give 0.366 g of calcium carbonate precipitate. What i

In-s [12.5K]

Answer:

81.26% is the percent yield

Explanation:

Based on the reaction:

CaCl₂ + Na₂CO₃ → 2NaCl + CaCO₃

Where 1 mole of CaCl₂ in excess of sodium carbonate produces 1 mole of calcium carbonate.

To solve this question we must find the moles of CaCl2 added = Moles CaCO₃ produced (Theoretical yield). The percent yield is:

Actual yield (0.366g) / Theoretical yield * 100

Moles CaCl₂ = Moles CaCO₃:

0.0500L * (0.0900moles / L) = 0.00450 moles of CaCO₃

Theoretical mass -Molar mass CaCO₃ = 100.09g/mol-:

0.00450 moles of CaCO₃ * (100.09g / mol) = 0.450g of CaCO₃

Percent yield = 0.366g / 0.450g * 100

81.26% is the percent yield

3 0

3 years ago

What caused our solar system to form by pulling together gases and dust in a nebula?

Furkat [3]

I’m pretty sure it’s gravity man

5 0

2 years ago

CaO + H2O -> Ca(OH)2

yawa3891 [41]

The % yield of Ca(OH)₂ : 62.98%

<h3>Further eplanation </h3>

Percent yield is the compare of the amount of product obtained from a reaction with the amount you calculated

General formula:

Percent yield = (Actual yield / theoretical yield )x 100%

An actual yield is the amount of product actually produced by the reaction. A theoretical yield is the amount of product that you calculate from the reaction equation according to the product and reactant coefficients

Reaction

CaO + H₂O ⇒ Ca(OH)₂

mass CaO= 4.2 g

mol CaO(MW=56,0774 g/mol) :

$\tt mol=\dfrac{mass}{MW}\\\\mol=\dfrac{4.2}{56,0774 g/mol}\\\\mol=0.075$

mol Ca(OH)₂ based on mol CaO

mol ratio CaO : Ca(OH)₂,= 1 : 1, so mol Ca(OH)₂ = 0.075

mass Ca(OH)₂(MW=74,093 g/mol) ⇒ theoretical

$\tt mass=mol\times MW\\\\mass=0.075\times 74,093 g/mol\\\\mass=5.557~g$

% yield :

$\tt =\dfrac{actual}{theoretical}\times 100\%\\\\=\dfrac{3.5}{5.557}\times 100\%\\\\=62.98\%$

8 0

2 years ago

Americans eat too much salt (NaCl). A healthy adult should eat no more than 6 g of salt in one day. Use this information to answ

Rufina [12.5K]

Answer:

a. 58.5 g/mol

b. 0.1 mol

Explanation:

The molar mass of Na is 23.0 g/mol. The molar mass of Cl is 35.5 g/mol. The molar mass of NaCl is:

M(Na) + M(Cl) = 23.0 g/mol + 35.5 g/mol = 58.5 g/mol

b. A healthy adult should eat no more than 6 g of salt in one day. The moles corresponding to 6 g of NaCl are:

6 g × (1 mol/58.5 g) = 0.1 mol

7 0

3 years ago