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1 year ago

Which of the following are examples of elements? a. CO b. Li c. KBr d. Ca

Chemistry

2 answers:

bogdanovich [222]1 year ago

6 0

$\huge\boxed{\textsf{Li and Ca}}$

An element is a substance that can't be broken down further. Lithium (Li) and calcium (Ca) are examples of elements.

Carbon monoxide (CO) and potassium bromide (KBr) are examples of compounds, which are made up of more than one element put together.

Fantom [35]1 year ago

3 0

You can check the Periodic Table of Elements to see that Li and Ca are elements and cannot be broken down. The correct answers are B and D.
Have a good day.

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3. How many moles of silver is 8.46x1024 atoms of<br> silver?

ioda

Answer:

<h2>14.05 moles</h2>

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

$n = \frac{N}{L} \\$

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

$n = \frac{8.46 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 14.053156$

We have the final answer as

<h3>14.05 moles</h3>

Hope this helps you

6 0

1 year ago

A weak acid, HF, is in solution with dissolved sodium fluoride, NaF. If HCl is added, which ion will react with the extra hydrog

kumpel [21]

Answer:

c. F1-

Explanation:

In this chemical reaction the expression is:

HF + NaF → NaHF2

The ion that always keep the negative charge is the fluorine with a -1, if in this mixture there is more positive ions (H1+) the negative ion (F1-) will join with them.

Remember that also the Cl1- will be free, but the fluorine is more reactive than the fluorine.

5 0

2 years ago

2C4H10(g) +13O2(g) → 8CO2(g) +10H2O(g) Suppose a grill lighter contains 50.0 g of butane. How many grams of butane in the lighte

MatroZZZ [7]

Answer is: mass of butane is D)11.6 g.
m(butane) = 50,0 g.
V(CO₂) = 17,9 L.
n(CO₂) = V(CO₂) ÷ Vm.
n(CO₂) = 17,9 L ÷ 22,4 L/mol.
n(CO₂) = 0,8 mol.
From chemical reaction n(CO₂) : n(C₄H₁₀) = 8 : 2.
n(C₄H₁₀) = 0,8 mol ÷ 4.
n(C₄H₁₀) = 0,2 mol.
m(C₄H₁₀) = n(C₄H₁₀) · M(C₄H₁₀).
m(C₄H₁₀) = 0,2 mol · 58 g/mol.
m(C₄H₁₀) = 11,6 g.

8 0

2 years ago

DNA is packaged into these<br> compact units

Wittaler [7]

Explanation:

Chromosomal DNA is packaged inside microscopic nuclei with the help of histones. These are positively-charged proteins that strongly adhere to negatively-charged DNA and form complexes called nucleosomes. Each nuclesome is composed of DNA wound 1.65 times around eight histone proteins.

4 0

2 years ago

Read 2 more answers

A process uses 63,400 SCF/h of natural gas. What is the annual cost of natural gas used in the process?

artcher [175]

Explanation:

It is known that 1 SCF produces approximately 1000 Btu of thermal energy.

As it is not mentioned for how many hours the gas is used in this process. Therefore, we assume that the total number of hours natural gas used in this process are as follows.

$365 \times 24$ = 8760 hours

Now, we will calculate the annual cost of natural gas used in the process as follows.

$8760 \times 63400$

= 555384000 SCF

Hence, annual cost of natural gas used in this process = loss of thermal energy

This will be equal to, $555384000 \times 1000$

= 555,384,000,000 BTU

Thus, we can conclude that the annual cost of natural gas used in the process is 555,384,000,000 BTU.

4 0

2 years ago