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3 years ago

8

What is science? Why do you think science is important?

1 answer:

ryzh [129]3 years ago

3 0

Answer:

Science is the study of the physical or material world. Science is important because it can answer questions about new ideas and can advance technologies

Explanation:

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Can someone help me with this I've been stuck on it for a few days

Fiesta28 [93]

So I haven’t got time to answer all of it for you but the id you look at the picture of the periodic table I’ve added the top number in the red boxes are the groups and the period is how many elements down from the top it is (remember that the hydrogen and helium make up period ONE) so remember to include them when counting the elements as you go down the table

5 0

2 years ago

Which of the following elements will lose electrons to form an

photoshop1234 [79]

B and c...will lose electron(s) in forming an Ion.

P is an Anion
b..Fe. and c...Pb form Cations (+) by losing electrons.
d. Se is an Anion.

4 0

3 years ago

In a lab experiment 80.0 g of ammonia [NH3] and 120 g of oxygen are placed in a reaction vessel. At the end of the reaction 72.2

valentinak56 [21]

The percent yield of the reaction : 89.14%

<h3>Further explanation</h3>

Reaction of Ammonia and Oxygen in a lab :

<em>4 NH₃ (g) + 5 O₂ (g) ⇒ 4 NO(g)+ 6 H₂O(g)</em>

mass NH₃ = 80 g

mol NH₃ (MW=17 g/mol):

$\dfrac{80}{17}=4.706$

mass O₂ = 120 g

mol O₂(MW=32 g/mol) :

$\tt \dfrac{120}{32}=3.75$

Mol ratio of reactants(to find limiting reatants) :

$\tt \dfrac{4.706}{4}\div \dfrac{3.75}{5}=1.1765\div 0.75\rightarrow O_2~limiting~reactant(smaller~ratio)$

mol of H₂O based on O₂ as limiting reactants :

mol H₂O :

$\tt \dfrac{6}{5}\times 3.75=4.5$

mass H₂O :

4.5 x 18 g/mol = 81 g

The percent yield :

$\tt \%yield=\dfrac{actual}{theoretical}\times 100\%\\\\\%yield=\dfrac{72.2}{81}\times 100\%=89.14\%$

6 0

3 years ago

Answer the following questions based on the reaction below: NaOH(aq) + KHP(s) --> NaKP(aq)+H2O(I)

Natali [406]

Answer:

<u />

<u>a) 1.44g</u>

<u />

<u>b) 77.3%</u>

<u />

Explanation:

<u>1. Chemical balanced equation (given)</u>

$NaOH(aq)+ KHP(s)\rightarrow NaKP(aq)+H_2O(l)$

<u>2. Mole ratio</u>

$1molNaOH(aq):1molKHP(s)$

This is, 1 mol of NaOH will reacts with 1 mol of KHP.

<u />

<u>3. Find the number of moles in 72.14 mL of the base</u>

$Molarity=\text{number of moles of solute}/\text{volume of solution in liters}$

$\text{Volume of solution}=72.14mL=0.07214liters$

$\text{Number of moles of NaOH}=0.0978M\times 0.07214liter=0.007055mol$

<u>4. Find the number of grams of KHP that reacted</u>

The number of moles of KHP that reacted is equal to the number of moles of NaOH, 0.007055 mol

Convert moles to grams:

mass = number moles × molar mass = 0.007055mol × 204.23g/mol

mass = 1.4408 g.

You have to round to 3 significant figures: 1.44 g (because the molarity is given with 3 significant figures).

<u>5. Find the percentage of KHP in the sample</u>

The percentage is how much of the substance is in 100 parts of the sample.

The formula is:

% = (mass of substance / mass of sample) × 100

% = (1.4408g/ 1.864g) × 100 = 77.3%

7 0

3 years ago

What determines which element an atom is?

Lana71 [14]

C) number of protons.

4 0

3 years ago

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