The substances at the beginning of a chemical equation are called the ____
product
yield
chemical symbol
reactants
2. Multiple Choice
10 seconds
12 pts
In the equation, 2Mg + O2 ---> 2MgO, which are the reactants?
Mg and O
MgO
Mg and MgO
O and MgO
3. Multiple Choice
10 seconds
1 pt
Which of the following models best demonstrates a balanced chemical equation?
F
G
H
J
4. Multiple Choice
10 seconds
1 pt
The equation below represents a chemical reaction that occurs in living cells. How many atoms are represented in the reactants of this equation?
6 6
12 12
24 24
36 36
5. Multiple Choice
10 seconds
1 pt
In which of these compounds are there twice as many oxygen atoms as hydrogen atoms?
H3PO4
H2SO4
HCIO3
H20
6. Multiple Choice
10 seconds
1 pt
Coal contains carbon and other elements. Carbon dioxide forms when coal burns in the presence of oxygen. Which of these is the best evidence that a chemical reaction occurs when coal burns?
The shape of the coal changes
Oxygen is present
A new substance is produced
Coal is made up of more than one element
7. Multiple Choice
10 seconds
1 pt
What are Chemical Reactions?
It's when you mix substances.
a process in which atoms rearrange to form new substances
When something bubbles.
letter and numbers showing the types and number of atoms
8. Multiple Choice
10 seconds
1 pt
Which of the following is NOT evidence that that a chemical reaction has occurred?
produces light/heat
production of a gas
formation of a precipitate
melting
9. Multiple Choice
10 seconds
1 pt
A different chemical substance is formed when _____.
water boils
metal rusts
ice melts
rock is crushed
10. Multiple Choice
10 seconds
1 pt
A teacher is demonstrating physical and chemical changes to her class. Which action should she use to demonstrate a chemical change?