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2 years ago

Please help I will give brainiest‼️‼️‼️‼️‼️‼️‼️

Chemistry

1 answer:

telo118 [61]2 years ago

7 0

The scientific method is the method used for scientific discovery.

<h3>What is the scientific method?</h3>

The scientific method is the process or procedure which scientists follow in their discovery and explanation of natural phenomena.

The scientific method is as follows:

Observations/Questions
Hypothesis
Experiments
Results
Conclusions

Using the scientific method to determine if water is needed by plants to grow

Question: Is water needed for growth in plants?

Hypothesis: Plants need water

Independent variable: sunlight

Dependent variable: rate of evolution oxygen

Constant variable: sunlight and soil

Materials: Cupboard, soil, potted plant, water,

Procedure: One potted potted plant is watered, while the other is not watered. The length of the plant is measured after 10 days

Observation: The watered plant survived and grew while that which was not watered did not grow but died.

Conclusion: water is needed for growth in plants.

In conclusion, the scientific method can be used to determine if plants need water for growth.

Learn more about scientific method at: brainly.com/question/17274244

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What is he difference between ligaments and tendons

inn [45]

Tendons<span> may also attach muscles to structures such as the eyeball. A </span>tendon<span> serves to move the bone or structure. A </span>ligament<span> is a fibrous connective tissue which attaches bone to bone, and usually serves to hold structures together and keep them stable.</span>

7 0

3 years ago

Read 2 more answers

How many oxygen molecules in 2.3x10-⁸g of molecular oxygen

cluponka [151]

Answer:

6.321 × 10^22

Explanation:

Mass of Oxygen =

3.36

Molar mass of oxygen (

) = 16 x 2 =

−

Total molecules in oxygen = Mass in grams/Molar mass x

3.36

6.02

6.321

Note:

(Avagadro's number) =

6.02

Hope it helps...

3 0

3 years ago

Calculate Delta H in KJ for the following reactions using heats of formation:

lozanna [386]

Answer:

$\Delta H\textdegree = -2856.8\;\text{kJ}$ per mole reaction.

$\Delta H\textdegree = -22.3\;\text{kJ}$ per mole reaction.

Explanation:

What is the standard enthalpy of formation $\Delta H_f\textdegree{}$ of a substance? $\Delta H_f\textdegree{}$ the enthalpy change when one mole of the substance is formed from the most stable allotrope of its elements under standard conditions.

Naturally, $\Delta H_f\textdegree{} = 0$ for the most stable allotrope of each element under standard conditions. For example, oxygen $\text{O}_2$ (not ozone $\text{O}_3$ ) is the most stable allotrope of oxygen. Also, under STP $\text{O}_2$ is a gas. Forming $\text{O}_2\;(g)$ from itself does not involve any chemical or physical change. As a result, $\Delta H_f\textdegree{} = 0$ for $\text{O}_2\;(g)$ .

Look up standard enthalpy of formation $\Delta H_f\textdegree{}$ data for the rest of the species. In case one or more values are not available from your school, here are the published ones. Note the state symbols of the compounds (water/steam $\text{H}_2\text{O}$ in particular) and the sign of the enthalpy changes.

$\text{C}_2\text{H}_6\;(g)$ : $-84.0\;\text{kJ}\cdot\text{mol}^{-1}$ ;
$\text{CO}_2\;(g)$ : $-393.5\;\text{kJ}\cdot\text{mol}^{-1}$ ;
$\text{H}_2\text{O}\;{\bf (g)}$ : $-241.8\;\text{kJ}\cdot\text{mol}^{-1}$ ;
$\text{PbO}\;(s)$ : $-217.9\;\text{kJ}\cdot\text{mol}^{-1}$ ;
$\text{PbO}_2\;(s)$ : $-276.6\;\text{kJ}\cdot\text{mol}^{-1}$ ;
$\text{Pb}_3\text{O}_4\;(s)$ : $-734.7\;\text{kJ}\cdot\text{mol}^{-1}$

How to calculate the enthalpy change of a reaction $\Delta H_\text{rxn}$ (or simply $\Delta H$ from enthalpies of formation?

Multiply the enthalpy of formation of each product by its coefficient in the equation.
Find the sum of these values. Label the sum $\Sigma (n\cdot \Delta_f(\text{Reactants}))$ to show that this value takes the coefficients into account.
Multiply the enthalpy of formation of each reactant by its coefficient in the equation.
Find the sum of these values. Label the sum $\Sigma (n\cdot \Delta_f(\text{Products}))$ to show that this value takes the coefficient into account.
Change = Final - Initial. So is the case with enthalpy changes. $\Delta H_\text{rxn} = \Sigma (n\cdot \Delta_f(\textbf{Products})) - \Sigma (n\cdot \Delta_f(\textbf{Reactants}))$ .

For the first reaction:

$\Sigma (n\cdot \Delta_f(\text{Reactants})) = 4\times (-393.5) + 6\times (-241.8) = -3024.8\;\text{kJ}\cdot\text{mol}^{-1}$ ;
$\Sigma (n\cdot \Delta_f(\text{Products})) = 2\times (-84.0) + 7\times 0 = -168.0\;\text{kJ}\cdot\text{mol}^{-1}$ ;
$\begin{aligned}\Delta H_\text{rxn} &= \Sigma (n\cdot \Delta_f(\textbf{Products})) - \Sigma (n\cdot \Delta_f(\textbf{Reactants}))\\ &= (-3024.8\;\text{kJ}\cdot\text{mol}^{-1}) - (-168.0\;\text{kJ}\cdot\text{mol}^{-1})\\ &= -2856.8\;\text{kJ}\cdot\text{mol}^{-1} \end{aligned}$ .

Try these steps for the second reaction:

$\Delta H_\text{rxn} = -22.3\;\text{kJ}\cdot\text{mol}^{-1}$ .

6 0

3 years ago

What property of water allows water to work as a universal solvent?

fgiga [73]

Answer:

The water is universal solvent because it is a polar molecule.This have hydrogen bonding in which hydrogen molecule have positive charge and oxygen molecule have negative charge because electro negativity of oxygen molecule is higher than hydrogen molecule that is why it pull the hydrogen molecule and formed a polar molecule.That is why is also known as universal solvent.

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4 years ago

What type of plate boundary is near mount manaro

iogann1982 [59]

Mexico the golf then the city of mexico

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3 years ago