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galina1969 [7]
2 years ago
7

HELP PLEASE 15 POINTS

Chemistry
1 answer:
dem82 [27]2 years ago
3 0

Answer:

The answer is letter A.

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The number of mole of a molecule is defined as its mass per molar mass. Using # mol = n, mass = m and molar mass = M and given t
Citrus2011 [14]
Given:
n = 0.0021 mol
M = 44 gram/mol

Required: m or the mass of the molecule

Solution:

M = m/n

Rearranging the expression,

m = M x n
m = 44 g/mol x 0.0021 mol

Evaluating the expression and cancelling units, we obtain,

m = 0.0924 grams

M is the molar mass. This value is very useful in chemistry calculations especially in calculating the amounts of reactants and products for a chemical reaction.
5 0
3 years ago
How many significant figures are needed in the answer when 1.31m is multiplied by 6.5 m​
dmitriy555 [2]

Answer:

two

Explanation:

The number of significant figures needed in the answer is 2.

This is because when finding the products of two numbers, the result is as accurate as the least number of significant figures of the numbers being multiplied.

Here the numbers being multiplied are;

 1.31m

 6.5m

        1.31m has 3 significant figures

          6.5m has 2 significant figures.

So, the product will have 2 significant figures

6 0
2 years ago
Which of the following rules should you follow to balance chemical equations?
Firdavs [7]

Answer:

c. add coefficients as needed

Explanation:

A chemical equation is defined as the equation that shows changes in a chemical reaction. A chemical equation consist of reactant and product, reactant is at left side of the arrow and product is at right side of the arrow.

Reactant => Product

While balancing a chemical equation, the basic rule is to balance the coefficient as required. Coefficient represents the number of molecules and is used at front of a chemical symbol. Change in coefficient helps balance the number of atoms or molecules of the substances on both the sides of the arrow.

Subscripts are never allowed to change because it can change the chemical involved in the reaction.

Hence, the correct answer is "c. add coefficients as needed".

3 0
2 years ago
At the same temperature, a freshwater lake frezzes but a salt water bay does not because
Alexandra [31]

Ocean water freezes at a lower temperature than freshwater. ... Fresh water freezes at 32 degrees Fahrenheit but seawater freezes at about 28.4 degrees Fahrenheit , because of the salt in it.

3 0
3 years ago
How many mL of a 0.250M sodium hydroxide solution is needed to neutralize 25.0 mL of a 0.430M sulfuric acid solution?
kotykmax [81]

Answer:

86.0 mL

Explanation:

i just did the USA test prep

5 0
3 years ago
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