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2 years ago

Science 7 Grade 7. Can anyone please help me answer these science questions?

Chemistry

2 answers:

masha68 [24]2 years ago

6 0

A cellphone battery is a electrical energy
and a piston in an engine is an thermal energy

NARA [144]2 years ago

4 0

<span>Thermal expansion in a balloon occurs because when the balloon is heated up, the gas molecules will move faster and in greater distance so when if they move faster then they will hit the wall with greater force, will result to expansion.

conduction, convection and radiation are the ways that thermal energy is transferred.

a cellphone battery is an electrical energy, then piston in an engine is mechanical energy </span>

You might be interested in

Discuss elements and compounds by completing the following paragraph

pychu [463]

Elements are substances that are made up of the same atoms which are capable of taking part in a chemical reaction.

There are different types of elements which are represented by symbols gotten from the first letter or the first and any other letter in the name of the element.

Examples of elements include:

Hydrogen (H)

Carbon (C)

Nitrogen (N)

Sodium (Na)

When two or more of these elements combine together through a chemical bond, it leads to the formation of compounds.

Example of a compound includes:

NaCl: The element sodium combine, through electrochemical bonding, with another element chlorine to form the compound sodium chloride.

Learn more here:

brainly.com/question/17571315

3 0

2 years ago

8. How many atoms of cobalt are in a 0.39 mole sample of CoC

Debora [2.8K]

8.98

cobalt atoms

Explanation:

Avogadro's number

specifies

6.0221

individual particles. It is simply another collective number like a dozen, or a score, or a gross.

has the property that

6.0221

individual cobalt atoms has a mass of

58.93

⋅

. How did I know that? Did I have it memorized?

So the quantity is

≈

cobalt atoms.

3 0

2 years ago

If 10.0 grams of NaHCO3 is added to 10.0 g of HCl, determine the efficiency of baking soda as an antacid if 6.73 g of NaCl was p

Lapatulllka [165]

Answer:

percentage yield of NaCl = 96.64%

Explanation:

The reaction was between NaHCO3 and HCl .The chemical equation can be represented below:

NaHCO3 + HCl → NaCl + H2O + CO2 . The balance equation is

NaHCO3 + HCl → NaCl + H2O + CO2

The question ask us to calculate the percentage yield of NaCl.

The efficiency of NaHCO3 as an antacid , the limiting reactant is NaHCO3

1 mole of NaHCO3 produces 1 mole of NaCl

Therefore,

molar mass of NaHCO3 = 23 +1 + 12 + 48 = 84 g

molar mass of NaCl = 23 + 35.5 = 58.5 g

1 mole of NaHCO3 = 84 g

1 mole of NaCl = 58.5 g

since 84 g of NaHCO3 produces 58.5 g of NaCl

10 g of NaHCO3 will produce ? grams of NaCl

cross multiply

Theoretical yield of NaCl = (10 × 58.5)/84

Theoretical yield of NaCl = 585/84

Theoretical yield of NaCl = 6.9642857143 g

percentage yield of NaCl = actual yield/theoretical yield × 100

percentage yield of NaCl = 6.73/6.9642857143 × 100

percentage yield of NaCl = 673/6.9642857143

percentage yield of NaCl = 96.635897436%

percentage yield of NaCl = 96.64%

3 0

2 years ago

Read 2 more answers

Suppose a 2.95 g of potassium iodide is dissolved in 350. mL of a 62.0 m M aqueous solution of silver nitrate. Calculate the fin

STALIN [3.7K]

Answer : The final molarity of iodide anion in the solution is 0.0508 M.

Explanation :

First we have to calculate the moles of $KI$ and $AgNO_3$ .

$\text{Moles of }KI=\frac{\text{Mass of }KI}{\text{Molar mass of }KI}$

Molar mass of KI = 166 g/mole

$\text{Moles of }KI=\frac{2.95g}{166g/mole}=0.0178mole$

and,

$\text{Moles of }AgNO_3=\text{Concentration of }AgNO_3\times \text{Volume of solution}=0.0620M\times 0.350L=0.0217mole$

Now we have to calculate the limiting and excess reagent.

The given chemical reaction is:

$KI+AgNO_3\rightarrow KNO_3+AgI$

From the balanced reaction we conclude that

As, 1 mole of KI react with 1 mole of $AgNO_3$

So, 0.0178 mole of KI react with 0.0178 mole of $AgNO_3$

From this we conclude that, $AgNO_3$ is an excess reagent because the given moles are greater than the required moles and KI is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of $AgI$