Answer:
We have 1.361 moles in the sample
Explanation:
Mass of iron = 76.02g
Molar mass of iron = 55.845 g/ mole ( This we can find in the periodic table, and menas that 1 mole of iron has a mass of 55.845 g).
To calculate the number of moles we will use following formula:
moles (n) = mass / molar mass
moles iron = 76.02g / 55.845 g/ mole
moles iron = 1.36127 moles
To use the correct number of significant digits we use the following rule for multiplication and division :
⇒ the number with the least number of significant figures decides the number of significant digits.
⇒76.02 has 4 digits ( 2 after the comma) and 55.845 has 5 digits (3 after the comma).
⇒ this means 1.361 moles
We have 1.361 moles in the sample
Answer:
1 mole of aluminum must contain 6.022⋅1023 atoms of aluminium → this is known as Avogadro's constant.
Explanation:
If Ka for HCN is 6. 2×10^−10 at 25 °C, then the value of Kb for cn− at 25 °C is 1.6 × 10^(-5).
<h3>What is base dissociation constant? </h3><h3 />
The base dissociation constant (Kb) is defined as the measurement of the ions which base can dissociate or dissolve in the aqueous solution. The greater the value of base dissociation constant greater will be its basicity an strength.
The dissociation reaction of hydrogen cyanide can be given as
HCN --- (H+) + (CN-)
Given,
The value of Ka for HCN is 6.2× 10^(-10)
The correlation between base dissociation constant and acid dissociation constant is
Kw = Ka × Kb
Kw = 10^(-14)
Substituting values of Ka and Kw,
Kb = 10^(-14) /{6.2×10^(-10) }
= 1.6× 10^(-5)
Thus, the value of base dissociation constant at 25°C is 1.6 × 10^(-5).
learn more about base dissociation constant :
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I might not be right but I think the empirical formula is NO2
Answer:
C.)organs are a group of two or more different types of tissues that work together to perform a specific function
Explanation:
Cells of similar function are grouped together into tissues. For example, cardiac muscle tissue is present only in the heart, and made up of specialised cells called cardiomyocytes, or cardiac muscle cells. These cells contract to pump blood around the body.
The heart is an organ, consisting of multiple types of tissue including cardiac muscle tissue, connective tissue, blood vessels and epithelial tissue. Therefore, organs represent a group of at least two types of tissue that work together to carry out functions in the body.