3 years ago

1.Grassland are where most of our_____ comes from?

Chemistry

2 answers:

-Dominant- [34]3 years ago

6 0

The answer is B. Crops used as food

Dafna11 [192]3 years ago

3 0

Answer is B.crops used as food

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Identify the charges = Mg2+ F1

gladu [14]

Answer:

its called drop and swap

Explanation:

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3 years ago

Which of these metals reacts more vigorously with water? <br><br> 1. Zinc <br> 2. Magnesium

GalinKa [24]

Answer:

magnesium

Explanation:

because zinc does not react with water because it too forms a protective layer of insoluble.

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2 years ago

Layers of rock containing fossils, like the layers illustrated here, are MOST LIKELY composed of ______________ rocks. A) igneou

Ilya [14]

The answer should be B:Sedimentry

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The combustion of propane may be described by the chemical equation C 3 H 8 ( g ) + 5 O 2 ( g ) ⟶ 3 CO 2 ( g ) + 4 H 2 O ( g ) C

Kipish [7]

Answer: 72 grams of $O_2(g)$ are needed to completely burn 19.7 g $C_3H_8(g)$

Explanation:

According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number $6.023\times 10^{23}$ of particles.

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Putting in the values we get:

$\text{Number of moles}=\frac{19.7g}{44g/mol}=0.45moles$

$C_3H_8(g)+5O_2(g)\rightarrow 3CO_2(g)+4H_2O(g)$

According to stoichiometry:

1 mole of $C_3H_8$ requires 5 moles of oxygen

0.45 moles of $C_3H_8$ require= $\frac{5}{1}\times 0.45=2.25$ moles of oxygen

Mass of $O_2=moles\times {\text {Molar mass}}=2.25\times 32=72g$

72 grams of $O_2(g)$ are needed to completely burn 19.7 g $C_3H_8(g)$

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3 years ago

What kind of changes occur between atoms when substances undergo chemical reactions?

KatRina [158]

The atoms undergo chemical changes.

New substances may be a product of the reaction.

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3 years ago